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Basic Immunology – repetition for Disorders of Immunity
Main functions of the immune system:
The defense against foreign invaders and protection of the organism
Autotolerance - self-tissue recognition and the maintenance of the tolerance
Immune surveillance - recognition of the internal antigens (old, damaged structures,
mutated cells)
Innate and adaptive immunity
Feature
Nonspecific, innate immune response
Specific, adaptive
Physical barriers
skin and mucosal membranes
none
Soluble factors
enzymes (lysozym, complement)
antibodies
Acute phase reaction proteins
lymphokins
(CRP)
IF-, IF-
Cells
Macrophages, PMN, eosinophils
T and B
lymphocytes
NK cells
Self, non self
yes
yes
Specificity
no
yes
Memory
no
yes
Structure of the immune system
Central: Thymus-environment for T lymphocytes development, bone marrow (Bursa of
Fabricius)
Peripheral: Lymphatic nodes, spleen, mucus associated lymphoid tissue (MALT)
Complement - the biological role
Biological consequences of complement activation, anaphylatoxic activity (C3a,C5a),
chemotactic activity (C3a, C5a), opsonization activity (C3b), bactericidal activity ( C5-C9),
immune complex presentation (indirect C3b, C3a)
Cytokines:
Soluble mediators secreted by Ly, Mo, Macrophages, stimulatory, inhibitory signals between
cells. Chemokines. Common features of cytokines:Half-lives are short, rapidly degraded, most
act locally, pleiotropic function, biologically overlapping functions
HLA system - Differentiation self/nonself
Class I
Class II
Antigens
HLA A, B, C
HLA DR, DQ, DP
Gene localization
Chromosome 6
Chromosome 6
Structure
Alpha 1, 2, 3, beta2m
Alpha 1, 2, beta 1, 2
Tissue distribution
each cell
Immunocompetent cells, esp.
B cells, activated T
cells, macrophages, inflamed endothelium
Function
Ag presentation
Ag presentation to T
to T cells CD8+.
cells CD4+,
Cytolysis
Necessary for interaction btw
of virus infected cell
Immunocompetent cells
T lymphocyte function
CD4-8+
CD4+8CD4-8CD4+8+
MHC.
Class I
Class II
?
?
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Function
% of T cells
TCR Type
2
cytotoxicity
25
/
help
70
/
cytotoxicity
4
/
?
1
/
Immunodeficiency
Primary -missing enzyme,missing cell type, nonfunctional component. Prevalent in childhood
Secondary due to underlying disease or event. Prevalent at any age, less severe
2.1 Primary Immunodeficiency
Antibody deficiency clues from history
Recurrent sinus, chest infections are common (history of repeat ENT surgery), another system is
usually involved (skin sepsis – abscesses, gut infection, meningitis), infections are bacterial and
due to common organisms (Strepto pneumoniae, Hemofilus influenzae)
Noninfectious features are common (autoimmune thyroid disease, immunotrombocytopenic
purpura, arthritis)
Designation
Immunoglobulins
Pathogenesis
Inheritance
1. X-linked agammaglobulinemia All isotypes decreased
Mutations in btk
XL
2. Selective Ig deficiency
IgA def.
Decrease IgA1, IgA2
Failure of terminal differentiation Variable
of IgM1 B cells
IgG subcl.def.
Decrease in 1 or more subcl.
Def. of isotype dif.
Unknown
3. Common variable ID
Decrease in IgG and usually
Unknown
Variable
IgA, +- IgM
4. X-Hyper IgM syndrome
Decrease in IgG, IgA,
Mutation in CD40 ligand
XL
IgM usually elevated
5. Transient hypogamaglobulinemia IgG,IgA low
Delayed helper function Unknown
in infancy
6. Antibody deficiency with
Normal
Unknown
Unknown
normal or elevated Ig levels
Management of antibody deficiency: Ig replacement therapy, treatment of infection, gene therapy, BMT
2.2 Combined, dominantly cellular immunodeficiency
Clues from history: Present in first few weeks/months of life, infections are often viral or fungal
rather then bacterial, chronic diarrhea is common and often labeled as “gastroenteritis”,
respiratory infections and oral thrush are common, failure to thrive in absence of obvious
infections should be investigated
Lymphopenia is present in almost all affected infants
Designation
Ig
Circulating B T cells
Pathogenesis Inheritance
1. T-B+SCID
Decreased
Normal or incr. Low
 chain mutation
Jak 3 mutation
XL
AR
2. T-B- SCID
RAG 1/2 deficiency
Decreased
Normal or incr. Low
AR
Decreased
Low
Low
Decreased
Low
Low
Mutation in
RAG1/2 genes
T, B cells defect AR
from toxic metabolites
Stem cell defect AR
Adenosin deaminase
deficiency
Reticular dysgenesis
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3. T+B- SCID
Decreased
4. Purin nucleoside
phosphorylase def.
Normal or low
Low
Present
Restricted heterogeneity Missense mutation
in RAG1/2 genes
Normal
Low
T cell defect from toxic metabol.
AR
AR
Management: Antimicrobial therapy, bone marrow transplantation, gene therapy
2.3 Primary ID with non-immunological features
DiGeorge anomaly (ID, hypoparathyroidism, cardiovascular defects), chronic mucocutaneal
candidiasis, ataxia teleangiectasia, Wiskot-Aldrich syndrome
2.4 Primary defects of non-specific immunity
Infections are recurrent and prolonged, clinical features may be minimal despite severe infection
Infections are: poorly responsive to antibiotics, common staphylococcal, involve skin and
mucous membranes, complicated by suppurative lymphadenopathy
2.4.1 Neutrophil defects
Chronic granulomatous disease, Hyper IgE, Chediak Higashi, LAD sy
Treatment: Antibiotic treatment and prophylaxis, Gamma interferon, BMT
2.4.2 Complement deficiency
Def C1, C2, C4
Immuno-complex diseases
D, B, P
Recurrent Neisserial infection
Def C3
Recurrent bacterial infection
C 1 inhibitor deficiency
hereditary angioedema
2.5 B.
Secondary immunodeficiency
Secondary causes of immunodeficiency are far more common than primary immunodeficiency.
Decreased synthesis
Malnutrition, lymphoproliferative diseases, drugs, infection (viral infection, chronic infection),
alcoholism (maternal), irradiation, major surgery, anesthesia, some chronic diseases (diabetes)
Increased loss – nephrotic syndrome, protein-loosing enteropathy, burns
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Autoimmunity and autoimmune diseases
Autoimmunity is an immune response against self antigen or antigens. Autoimmune disease is
tissue damage or disturbed physiological function due to autoimmune response. (Autoimmune
response can occur without disease, caution is required in making the assumption that
autoimmune responses necessarily imply autoimmune disease)
Slight autoimmune reactivity is normal, many self proteins induce an autoimmune response in
animals when injected with an appropriate adjuvant.
3.1.1 Ethiopathogenesis - Who gets autoimmune disease?
Around 3 % of the population have an autoimmune disease. Many of the major chronic disabling
diseases affecting people have autoimmune diseases.
Rare in childhood, peak between puberty and retirement age, more common in women,
prevalence higher in northern latitudes, higher in westernized industrial societies, clustering
within families
Central T-Cell tolerance (thymus) and peripheral mechanisms of the induction of tolerance
fail. Molecular mimicry - structural similarity between self proteins and those from
microorganisms may trigger autoimmune response. Once tolerance has broken down to a
particular peptide, the process of inflammation will allow presentation of further peptides –
epitope spreading
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3.1.2 Antigenic mimicry
Microbial protein
autoantigen
Streptococcal M protein
myocardial myosin
Nitrogenase from Yersinie
HLA B27
EBV EBNA-1
Reumatoid artritis synovial cells
EBV capside antigen
Human IgG
Adenoviral E1B protein
Gliadin protein A
Hepatitis B polymerase
Myelin basic protein
Coxsackie B4 nuclear protein
islet glutamate decarbocylase
HSP from M.tuberculosis
Human heat shock protein
Campylobacter jejuni glycoproteins
Myelin associated gangliosides and glycolipids
3.1.3 What triggers autoimmunity?
Genetic factors.
Multiple genetic factors may cluster within the same family. The genetic
contribution to autoimmune disease almost always involve multiple genes.
Association between HLA and diseases - examples
Rheumatoid arthritis
DR4+DR1
DM type I
DR3+DR4
SLE
DR3
Organ specific autoimmune DR3 (in association with A1B8DR3 Disease: Addison, thyroid,
pernicious anemia, myasthenia gravis
3.1.4 Environmental factors on autoimmunity development
Hormones
females are far more likely to be affected than males
Infection molecular mimicry, up-regulation of co-stimulatory molecules
Drugs
will induce pathological immune response-reversible with withdrawal Drug induced autoimmune syndrome
3.1.5 Treatment of autoimmune disease - Unsatisfactory !
Replacement of function, particularly endocrinological autoimmune disease, Immunosupression
(lack of specificity, toxic effects!!), bone marrow transplantation
3.2 Kidney disease - pathogenic mechanisms
Ab directly react with glomerular, tubular basal membrane antigens
Ag-Ab imunocomplexes are deposited in kidney or Ag my bind with glomerular BM and react
with the antibody
Ab may induce a vasculitis process that damages the capillary plexus of glomerulus.
Glomerulonephritis: Antibody, cell-mediated, acute, chronic
3.3 Autoimmune endocrine diseases
Thyroidal - Thyrotoxicosis (Graves disease), autoimmune thyroiditis (Hashimoto thyroiditis)
Type I DM,
Adrenal disease - AI adrenalitis, Addison disease
Gonadal disease.
AI polyendocrine syndrome
Type 1 parathyroid,adrenal cortex, gonads, mucocutaneous candidiasis
Type 2 adrenal, thyroid, insulitis
Type 3 thyroid, pernicious anemia or DM I, myasthenia
3.4 Autoimmune disease of joints and muscles
Immune mechanisms are responsible for many rheumatological diseases - joint, muscles, or
systemic involvement- „connective tissue diseases“ (CTD)
CTD typically associated with non-organ-specific diseases autoantibodies (AutoAb).
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AutoAb are diagnostically useful, not usually responsible for damage
Rheumatoid arthritis - Chronic, relapsing systemic inflammatory disease, joint usually involved
- destructive arthritis. Otherwise any organ
Main immunologic features - rheumatoid factors-IgM Ab which binds aggregated IgG, in serum
or synovial fluid, vasculitis, synovitis, decrease C level
Pathogenesis - probably CD 4+ cells promote macrophages to destroy joints, synovial infiltration
by CD4+ cells, association with DR4, effective therapy against T cells (Cy A), animal model
with T cell destruction
Seronegative arthritis - Ankylosing spondylitis - spine, SI joints
Reiter disease - artritis,urethritis, conj,-uveitis - T response to sequestrated bacterial
antigens
Reactive arthritis
Psoriatic arthropathy
Entheropatic arthritis - ulcerative colitis
Relapsing polychondritis - cartilage inflammation
Behcet disease
Lupus erythematosus
Systemic lupus erythematosus
Multisystemic inflammatory disease, characterized by antinuclear antibodies
ACR criteria (at least 4)
malar, diskoid rash, fotosenzitivity, oral ulcers, neerosive arthritis, serositis, renal involvement
(proteinuria,casts), neurological disorder (seizures/psychosis), hematological symptoms, ANA,
anti ds-DNA, anti-ENA, antiphospholipid antibodies
Imunopathogenesis SLE - Imunopathologic reaction type II. and III. Deposition of complexes
dsDNA – anti-DNA, deposition of Ig and complement - inflammations and tissue damage
Anti erythrocyte Ab, anti-platelet Ab, coagulation factors Ab - direct pathogenic role
Etiology of SLE – generally, unknown, suspected hypotheses follow:
Complement deficiency - Classical pathway defect (C1, C4, C3) is a risk factor.
Secondary deficiency by consumption maintains the inflammation
Autoantibody production directed against nuclear molecules involved in transcription and
translation. Infection induced? Defective apoptosis
Polyclonal B cell activation
Defective apoptosis (no FAS defect)
Drugs (slow acethylators) - hydralazin, prokainamid, INH
UV light - apoptosis induction on keratinocytes, Ro, La antigens expression
Hormones - estrogens accelerate the disease?
Other connective tissue disease
Mixed connective tissue disease (MCTD) - arthritis, polymyositis, lung fibrosis, skin, anti RNP
Sjogren syndrome - autoimmune destruction of exocrine glands
Systemic sclerosis, scleroderma- diffuse sclerosis of skin, GIT, heart, muscle
Vasculitis - polyarteritis nodosa - multiple aneurysm
Polymyositis - primary idiopathic PM/DM, with malignancy, juvenile DM, with other AI disease
3.5 Cardiovascular autoimmune diseases
The immunologic cardiovascular diseases are a diverse group of clinical entities that generally
are of either unknown cause or unproven pathophysiology. The conditions with a proven cause
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result from infections, with the best examples being acute rheumatic fever (ARF) and Lyme
disease.
3.5.1 Classification of vasculitic syndromes
Classification according the vessel size (large, medium and small muscular arteries, small
vessels). Inflammation within blood vessels that often results in a compromise of the vessel
lumen or vessel wall with aneurysm development, the clinical result is ischemia, which causes
the major manifestations and determines the prognosis of the vasculitic syndromes.
Polyarteritis nodosa - represents 7% of all forms of vasculitis. The disease is systemic but does not
usually affect the aorta, the primary branches of the aorta, or the elastic pulmonary arteries.
3.6 Neuroimmunology
Multiple sclerosis- pathogenesis - autoAg myelin basic protein induces T cells response
Myasthenia gravis - Ab against ACH receptor, associated with other AI diseases, thymoma
Immune mediated, inflammatory neuropathies - autoantibodies - anti MAG, gangliosides
(GM1,GM2), sulfatide
3.7 Bullous skin disease
Pemphigus
Most patients have circulating anti-desmosomal Ab (desmoglein 3), titer correlate with
disease activity, plasmapheresis reduce Ab titer and disease activity
Similar lesion can be induced in animals by patients serum
IgG from pemphigoid serum in the culture will cause epithelial cell detachment
Direct immunofluorescence is diagnostic- IgG, C3 react with keratinocytes
Treatments - systemic corticosteroids
Bullous pemphigoid
Dermatitis herpetiformis Duhring - itchy, small vesicles. Entheropathy similar to CD
Other autoimmune skin disease
Systemic sclerosis
Cryoglobulinemia - Ig which form precipitates, gels or crystals in the cold
Type I - monoclonal IgM
Type II - mixed type, IgM against Fc IgG
Type III - mixed polyclonal
Skin vasculitis - circulating IC, or ANCA
Hereditary angioedema – inborn defect of C1 Inactivator
Urticarial vasculitis
Urticaria - marked wheals with surrounding erythema
3.8 Autoimmune eye diseases
Stevens-Johnson sy - severe form of erythema multiforme - IC - drugs, microorganisms
Uveitis - anterior uveitis, posterior uveitis, lens-induced uveitis
3.9 Autoimmune chest diseases
Granulomatous diseases - TBC, sarkoidosis - multisystem granulomatous disorder
Interstitial diseases - Fibrosing alveolitis - cryptogenic f. alveolitis, pulmonary eosinophilia
Hypersensitivity pneumonitis (“Farmers lung”)
Vasculitis - M. Wegener, Goodpasture´ syndrom
Allergic bronchopulmonary aspergillosis
3.10 GIT and liver disease
Atrophic gastritis and pernicious anemia
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Gluten sensitive enteropathy – celiac disease – T cell response to gluten and gut Ag
(transglutaminase, calreticulin)
Inflammatory bowel disease - ulcerative colitis,Crohn disease
Hepatitis - infection - A, B, C
autoimmune - Type I – autoantibodies
ANA, ASMA
Type II
LKM (IIa), with virus hepatitis C (IIb)
Type III
SLA
Primary biliary cirrhosis – antimitochondrial antibodies are highly diagnostic
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Allergy and Anaphylaxis
Risk factors for allergic diseases –
Atopy
Age – commoner in children than adults
Gender – commoner in boys than girls
Family size – less common in large families
Smoking
High levels of antigen exposure
Dietary factors – good intrauterine nutrition
Atopy – inherited tendency for hyperproduction of IgE antibodies to common environmental
allergens.(about 80 % of atopic individuals have a family history of “allergy”¨).
4.1 Type I hypersensitivity – most of the reactions are IgE mediated – IgE mediated release of
preformed, newly generated mediators from mastocytes and basophils
Immediate reactions – wheal-flare reaction in 15-20 minutes (parenteral – reaction to
insect venom, drugs, direct activation of mast cells – aspirin, tartrazine, myorelacants, opioides,
activation via complement split products C3a, C5a)
Late-phase response - 4-6 h after exposure, lasting for 24 hours. (accumulation of
activated inflammatory cells - eosinophils and T lymphocytes)
4.2 Anaphylaxis
– generalized degranulation of senzitized mast cells and basophils after antigen exposure.
Clinically – sudden, generalized, severe, dominantly cardiovascular reaction or airway
obstruction (bronchospasm)
The most common causes of anaphylaxis – foods, drugs, bee and wasp venom,latex
rubber
Anaphylactoid reaction – (anaphylaxis-like reaction) is not mediated by IgE antibodies. Prior
sensitization is not needed.
4.3 Allergic conjunctivitis – seasonal (hay fever) and perennial. Vernal conjunctivitis –
perennial, self limiting conjunctivitis, with giant papillae on the upper tarsal conjunctiva.
4.4 Allergic rhinitis
Allergic rhinitis is the sixth most prevalent chronic disease in the USA.
Allergic – seasonal, perennial (pollen, mites, animal dander, molds)
Chronic rhinitis
Chronic hyperreactive, vasomotor (etiopathogenesis not known)
Medicamentosa
Size of antigen
Organ
Associated disease
>15 um
Nose
Allergic rhinitis
5 – 15 um
Bronchi
Asthma
< 5 um
Alveoli
Alveolitis
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4.5 Bronchial Asthma
Three cardinal features
Generalized, reversible airway obstruction
Bronchial hyperresposiveness
Airway inflammation
Asthma is simple to treat, difficult to manage, impossible to cure.
4.5.1 Precipitating factors in asthma
Specific antigenic factors – Seasonal tree, grass, weed pollen
Perennial – HDM, animal danders, feathers, fungal spores,
occupational allergens – metals
Non – specific factors
Infections
Irritants – smoking, fumes, diesel exhaust particles, sulfur dioxide,
some ingested foods and preservatives
Airway cooling – exercise, cold air temperature
Emotional stress
Features of asthma
Allergic asthma (AKA extrinsic)
Idiopathic (AKA intrinsic)
Others
Causes of eosinophilic infiltration is chronic allergen exposure
Upregulation of VCAM enable of eosinophil recruitment
Maturation and increased survival mediated by IL-3, IL-5 and GM-CSF
Selective eosinophil migration induced by IL-8 and RANTES
4.5.2 Pathological changes of asthma - epithelial cell shedding, subepithelial fibrosis, mucosal
edema, smooth muscle hypertrophy and hyperplasia, thickening of the basement
membrane, eosinohpil and mononuclear infiltration in the mucosa
4.6 Food allergy and intolerance
Adverse reactions to foods - food fad, psychological aversion, food intolerance (mechanism
unknown), food allergy, food idiosynkrazy (nonimmunological mechanism) – irritants,
pharmacological, metabolic effects, enzyme deficiency.
Food antigens, or other components in food – traces of antibiotics, food additives (monosodium
glutamate), coloring agents, preservatives
Clinical syndromes – acute angioedema, urticaria, perioral erythema, GI symptoms (children)
atopic eczema
Diagnosis of food allergy - Elimination and challenge diet form the basis of the diagnosis of food
allergy. Common in childhood
Skin test and IgE testing is not fully reliable
4.7 Urticaria and angioedema
Urticaria refers to transient episodes of demarcated, edematous, erythematous, pruritis lesions
with a raised edge. Clinical diagnosis is easy, finding the cause is very difficult
Angioedema is a similar process occurring in the deep dermis, subcutaneous tissue or mucous
membranes. Urticaria and angioedema commonly coexist.
Mechanisms of urticaria production - Immune mechanisms: IgE, complement, autoimmune FcRI
autoantibodies, association lwith other AI diseases
Direct action on mast cells – Aspirin, NSAID, ACE inhibitors, opioids, azo
dyes
Physical urticaria – itching and wheals are provoked by physical stimuli
(stroking, cold, sun, water, exercise, heat)
Urticarial vasculitis – immune complex disease, histological evidence of vasculitis
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Clinical identification wheals are usually tender, painful rather than itchy
Generally last longer than 24 hours
Wheals fade to leave purpura or bruising
Often accompanied by systemic features such as fever artralgia,
patients may have underlying disease (SLE)
Treatment differs
4.8 Atopic eczema
Common, chronic, severely pruritic, eczematous skin disease, usually in individuals with a
hereditary predisposition to atopic disorders
Prevalence
children under the age of 2 years – 10 %, adults
2%
Complication – bacterial superinfection
Diagnosis – on the basis of clinical features
Immunologic abnormality - raised serum total IgE in about 90 % of patients (nonspecific)
Abnormal T cell function – increased susceptibility to skin infection, normally controlled by T
cells (vaccinia, herpes simplex, viral warts)
Impaired delayed hypersensitivity skin test response
Decrease number of Th1 cells, expansion of Th2 cells, chronic macrophage activation
4.9 Contact dermatitis
Inflammatory skin disease caused by T-cell mediated hypersensitivity to external agents –
dominantly occupational disease
Agents responsible for contact dermatitis
Metals
nickel, chromate (cement), cobalt
Medication “para” -group chemicals – anesthetics, sulfonamide antibiotics, PABA containing
substances, phenothiazines, neomycin
Plastics
acrylates
Rubber
accelerators
Plants
Primula, Poison Ivy, chrysanthemum
Cosmetics
Perfumes, preservatives, lanolin
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Immunopathology of reproduction
Immunity related to conception, nidation, intrauterine tolerance, response to sperm antigens
(men, women), mother immune response during pregnancy
Sterility and infertility
Survival of fetus as a allograft - hemochorial placenta - syncitiotrofoblast - no HLA Class I
but class G expression, fetal antigens expressed weakly
Uterus is not a privileged site, mild exchange of soluble factors and cells between the mother and
the fetus (200 000 cells / day). Only IgG immunoglobulin can cross the placenta, autonomous
IgM,IgA production (infection), crossing Ab in case of incompatibility A,B,O or Rh = HDN,
crossing of autoantibodies - mother AI disease
Maternal immune response during pregnancy - decreased number of lymphocytes, decrease of
CD4 cells, increase of CD8 cells, decreased proliferative response of T lymphocytes, increased Ig
concentration
Immune reaction after repeated abortions - negative influence of the same HLA antigens therapy: immunization of mother by father antigens
Antiphospholipid antibodies, autoimmunity to trophoblast, endometrium
Immune response to sperms - man = autoimmunity, women = alloimmunity
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Transplantation immunology
6.1 Alloimmunity as an inflammatory response
In patients who are serologically presensitized to alloantigens (ie, graft antigens recognized as
"non-self"), this can rapidly proceed to a pathologic thrombotic response (hyperacute rejection).
When graft alloantigens are encountered by T cells, the inflammatory responses intensify, and
pathologic tissue destruction ensues (acute rejection).
When these T-cell-dependent responses to graft alloantigens are controlled by
immunosuppressive drugs, acute rejection is avoided, but tissue repair mechanisms are allowed to
engage.
If the repair and structural reinforcement process is prolonged, pathologic tissue remodeling
occurs (chronic rejection).
Mechanisms of tissue damage
antigen-independent causes of tissue damage associated with allograft transplantation, including
peritransplant ischemia, mechanical trauma, and reperfusion injury
antigen-dependent causes, such as immune-mediated damage to graft tissues. Any tissue
damage in the graft compromises graft acceptance by promoting graft inflammation, a
complicated array of events that promotes control, pathogen surveillance/eradication, and tissue
repair.
6.2 Pathways for the presentation of alloantigenic peptides
1. Proteins derived from graft cells are obtained by recipient antigen-presenting cells (APCs),
processed, and displayed via recipient major histocompatibility complex (MHC) class II molecules
to recipient CD4+ T cells.
2. Proteins produced by graft-derived antigen-presenting cells (APCs) are processed and
displayed via graft-associated major histocompatibility complex (MHC) class I molecules to the
recipient CD8+ T cells.
6.3 Types of graft rejection
Hyperacute rejection - Presence of large numbers of polymorphonuclear leukocytes
Occurs within minutes to hours of graft implantation. Dependent on the presence within the graft
recipient of preformed circulating antibodies with specificities for foreign protein
polymorphisms displayed by the graft endothelia (ABO, MHC encoded proteins)
1 %. Avoidance of high-risk donor-recipient combinations
Acute Rejection - Acute rejection is characterized by the presence of leukocytes macrophages and T cells. Within the interstitial infiltrate of acutely rejecting grafts is a small
number of recipient-derived, donor alloantigen-reactive T cells, on which the process of acute
rejection is absolutely dependent. 50 % . Immunosuppressive drugs
Chronic Rejection - Development of blood vessel luminal occlusion due to progressive
neointimal formation within the large to medium arteries and, to a lesser extent, veins of the graft
It represents a pathologic tissue-remodeling response. 10-year graft survival can be reliably
evaluated, chronic graft rejection occurs in about 50% of transplant patients
6.4 Selection of donor/recipient for kidney
Living relative - two kidneys, no transmissible disease, no anomalous blood vessels, good
psychologically health
Cadaver - good renal function, no infection, malignancy, systemic disease
Recipient selection - ABO compatible, negative serum crossmatch, HLA match, particularly D
loci
6.5 Pre - transplantation testing
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Blood group - A,B,O, HLA antigens Class I and II , Mixed lymphocyte culture – MLR,
Cross – match. Alloreactivitiy testing of T cells - mixture of donor and host lymphocytes
6.6 Stem cell transplantation - indication
Severe aplastic anemia, Acute/chronic myeloid leukemia-1st remission, acute lymfoblastic
leukemia, imunodeficiency - SCID, CGD, WA, hyper IgM - severe cases, inborn errors of
metabolism, autoimmune diseases - peripheral SC
6.7 Graft versus host disease - It occurs in most patients with allogenic transpants Presence of immunocompetent T cells in graft and HLA incompatibility between donor and
recipient. Role of cellular immune deficiency in the host
Graft versus host disease - clinical picture: Rash, fever, hepatosplenomegaly, bloody diarrhea,
breathlessness, 7 - 14 days after transplantation. Prevention - irradiated blood products in
immunosupresed hosts ( T cells inactivation), T cells depletion
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Immunohematology and lymphoproliferation
7.1
Immune reactions against blood elements
Hemolytic anemia, thrombocytopenia, neutropenia, soluble clotting factors, ("lupus
anticoagulant") antiphospholipid antibody (APA) syndrome, transfusion reactions
Two classes of antibodies, IgG and IgM, are each associated with distinctive serologic reactions
and different clinical forms of immune hemolytic anemia
Direct and indirect antiglobulin test - The direct antiglobulin test uses antihuman IgG Coombs
reagent to detect the presence of IgG antibodies bound to red blood cells (RBCs). Similarly,
complement deposition is detected using a reagent containing antihuman complement.
Autoimmune hemolytic anemia
Warm reactive IgG autoantibodies, best detected at 37 ° C
Cold reactive IgM autoantibodies, detected at the temperature bellow 37 ° C
Drug provoked immune hemolytic anemias
Complement activating IgG of paroxysmal cold hemoglobinuria
Classification of AIHA
warm (IgG) primary
secondary
lymphoproliferation, autoimmune disease
drugs, infection
cold (IgM)
primary
secondary – infection, lymphoproliferation
Warm autoimmune hemolytic anemia
Clearance of IgG-coated red blood cells (RBCs). Removal is mediated by attachment to
Fcgamma receptors located predominantly in the spleen. Red blood cells that survive this process
partially phagocytized become spherocytes, a characteristic morphologic feature of immune
hemolysis. The IgG-coated cells undergo accelerated destruction by attachment to Fc receptors
present on macrophages of the RES, primarily those located in the spleen
Cold agglutinin hemolytic anemia
Cold-reactive IgM autoantibodies fix early complement components to the red blood cell
membrane. Rewarming results in additional activation of the complement system, leading to
extravascular removal (hepatic RES cell C3 receptor binding) or intravascular destruction.
Paroxysmal cold hemoglobinuria is the rarest form of an autoimmune hemolytic disease. It
results from a cold-reacting IgG antibody (the Donath-Landsteiner antibody), usually with
specificity for a universal RBC determinant, the P antigen. The antibody fixes early complement
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components to the cell; on rewarming, the remainder of the complement sequence is activated,
leading to intravascular lysis
Drug-Induced Hemolysis
A large number of drugs are capable of causing immune hemolytic reactions in susceptible
individuals - (1) the drug adsorption type, (2) the immune complex type, (3) the autoantibody
type
Penicillin is the prototypical example of the drug adsorption mechanism (very high doses - 10 20 million U
7.2 Hemolytic disease of the newborn
Consequence of the binding of maternal alloantibodies or isoantibodies to the inherited paternal
antigens present on fetal RBCs, which the mother lacks
The commonest cause - rhesus incompatibility Rh D- women are at risk
Prevention - anti - D antibody after delivery in the first pregnancy (destroy Rh+ fetal cells)
7.3 Hemolytic transfusion reaction (HTR)
The most common cause of AHTR - the transfusion of ABO-incompatible RBCs because of a
clerical error
Delayed hemolytic transfusion reactions - a result of an anamnestic response from exposure to
minor RBC antigens, typically those belonging to the Rh, Kell, Kidd, or Duffy blood groups
7.4 Immune thrombocytopenia
Immune mechanisms similar to those described for RBCs can also cause thrombocytopenia
The major diagnostic criteria are: (1) a low platelet count, (2) evidence for a destructive cause of
the thrombocytopenia (e.g., large platelets in the peripheral blood, a bone marrow that shows
normal to increased numbers of megakaryocytes), (3) the absence of other causes of a destructive
thrombocytopenia.
7.5 Immune neutropenia
Neonatal alloimmune neutropenia (transient congenital neutropenia) occurs when maternal
neutrophil-specific antibodies cross the placenta. Drug induced neutropenia, secondary
neutropenia - SLE
7.6 Antibodies against clotting factors
The antibody is directed against a specific clotting factor, such as factor VIII antibodies (15 % of patients
with severe hemophilia, the antibody act as a nonspecific blocking factor (prothorombin converter
complex) - the lupus anticoagulant/APA - different antibodies, related pathogenesis of AP
syndrome
Lupus Anticoagulant/APA Syndrome
The lupus anticoagulant is an IgG or IgM antibody that prolongs clotting tests by binding to
anionic phospholipids that have formed complexes with proteins.
Lupus anticoagulants are one of the most common coagulation abnormalities seen in clinical
medicine and have been associated with thrombosis and recurrent fetal loss
7.7 Immunohematologic aspects of B-cell disorders
Clonal neoplasms, such as CLL, macroglobulinemia of Waldenstrom, and multiple myeloma, can
be considered to represent a maturation arrest in the normal sequence of the cellular responses of
B lymphocytes to antigenic stimulation.
B lymphoproliferative disease - Chronic lymphocytic leukemia, monoclonal gammopathies,
macroglobulinemia of Waldenstrom, amyloidosis - the extracellular tissue deposition of an
insoluble fibrillar protein. Cryoglobulinemia - proteins that precipitate when exposed to cold and
redissolve with rewarming.
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Tumor Immunology
Tumor immunogenicity - The protein products of these mutated DNA segments are potentially
immunogenic and have the potential to serve as rejection antigens recognized by the host immune
system. Defining the role of the host immune response toward these aberrant proteins in
preventing, controlling, and eliminating malignant cells
8.1 Mechanisms of escape of tumor cells from the immune system
Downregulation of MHC Class I expression
Lack of costimulatory function
Immunoselection of tumor cells with weak immunogenicity
Tolerance of the host to respond to tumor antigens
Supression of immune response by tumor secreted products
Induction of supressor cells
Tumor antigens that may induce T-Cell responses
8.2 Immunotherapy of cancer
Active Immunization - cytokines IL-2, IL-4, with tumor antigens
(tumor antigens may be able to elicit a strong immune response)
Passive immunization: With antibodies - To use antibodies that bind to antigens on tumor cell
surfaces to carry toxic agents to the tumor and selectively kill tumor cells
Radioimmunolocalization of metastatic disease using monoclonal antibodies (melanoma)
Anti-idiotypic antibodies have been used in the treatment of B-cell lymphomas
Adoptive immunotherapy with lymphoid cells
Generation of lymphokine-activated killer (LAK) cells
Tumor-infiltrating lymphocytes (TILs), are specific in their in vitro reactivity to tumor cells
Specific adoptive immunotherapy with lymph node-derived T cells
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9.1
Immunomodulation and immunotherapy
Immunotherapy
specific - immunization against infection
nonspecific - synthetic stimulators, bacterial lysates, derivates
Imunosuppression
nonspecific - synthetic drugs, cytokine intervention (AI,
transplantation, severe allergy)
specific - allergy, AI diseases (research)
Immunostimulation and correction treatment
Causal therapy of secondary ID
treatment of the disease, antimicrobial therapy, targeted
therapy of associated immune disorder
Causal therapy of primary ID
stem cell transplantation, gene therapy
substitution therapy - IVIG, complement, growth factors,
immunocompetent cells
9.2 Vaccination against infectious diseases
Active immunization
natural infection
artificial-mimic the immunological stimulus
Passive immunization
natural – placenta, breast milk crossing
artificial – hyperimmune serum
Ideal vaccine: effective, safe, cheap, ready available, stable, easy administered, with long last
effect
Immunostimulation
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Immunization is undergoing important changes, with improved vaccines replacing less
immunogenic or less safe vaccines, new vaccines for common diseases such as chickenpox and
hepatitis A infection, and improved immunization schedules.
Currently immunization is used to protect patients prior to exposure to an infectious agent or
during the incubation phase after exposure, but before disease has occurred.
9.2.1 Immunological requirements of a vaccine:
Activation of APC to initiate antigen processing and production of cytokines
Activation of both T and B cells to give a high yield of memory cells
Generation of T cells to several epitopes to overcome:
antigenic variation of pathogens
genetic variability in the host´s immune response due to MHC polymorphism
Persistence of antigen on follicular dendritic cells in lymphoid tissue where memory B
cells are recruited. Live attenuated vaccines fulfil these criteria par excellence
9.2.2 Vaccines
Live vaccines - infect, replicate, and immunize, without causing significant disease (BCG, PolioSabin, MMR) Not a fully virulent organism - attenuated - !!Risk for cellular ID!!
Killed vaccine - suspension of killed organisms (cholera) or products or fractions (pertussis).
Toxoids (tetanus), subunits of viruses (split vaccines)
Adjuvants - enhance the immune response to another antigen given simultaneously - Freund´s,
aluminum, muramyl dipeptid, polymers
Viral vaccines for active immunization
A.Produced by serial passage in cell culture (e.g., oral poliovirus vaccine); killed vaccines
-formalin
B. Subunits - surface components of a virus or bacteria or made from recombinant DNA
C. DNA vaccines: genetic information coding for a pathogen protein placed in a gene
transfer expression vector
9.2.3 Immunization schedule in the Czech Republic (recommended/obligatory)
4thday - 6thweek
TBC
9th - 12th week
Diphteria/tetanus/pertussis
10th - 18th wee
Polio
13th -16th week
Diphteria/tetanus/pertussis
17th - 20th week
Diphteria/tetanus/pertussis
14,5 - 20th week
Polio
15th month
Measles, mumps, rubella (MMR)
18th-20th month
Diphteria/tetanus/pertussis
21st - 25th month
Measles, mumps, rubella (MMR)
2nd year
TBC (tuberculin negative)
5th year
Diphteria/tetanus/pertussis
11th year
TBC (tuberculin negative)
12th year
rubella (nonvaccinated girls)
13 th year
Polio
14th year
Tetanus (revaccination in 10 years)
Currently, Hepatitis B, Hemophillus vaccines has been added
9.3 Nonspecific immunostimulation
Synthetic levamisol, isoprinosin
Bacterial immunomodulators
Products of immune system - transfer factor, thyme hormones, cytokines
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9.4 Immunosuppressive therapy
Indication:
AI disease, transplantation
Corticosteroids – known molecular effects of glucocorticosteroids
CS
metabolic effect, anti-inflammatory effect, blood elements traffic effect
Side effects!!
Doses low (rheumatoid arthritis) - 7,5 - 10 mg/day
high (AIHA, GN, ITP) - 1 - 2 mg/kg
pulse dose of methylprednisolon 10 - 30 mg/kg 2-3 consecutive days
IS targeted to DNA metabolism - antagonists and inhibitors of nucleotides - azathioprin,
mycofenolic acid, cyklofosfamid, antimetabolites
Immunosuppressive therapy - selective for immune cells - IS antibiotics - molds products, bound
to cytoplasmic immunophillins - transcription inhibition for gee for IL-2 - cyclosporin A, FK506
(tacrolimus), rapamycin
Antibodies to T cells - antilymphocyte serum, antithymocyte serum, anti CD3, anti CD4, CD25,
CDw52
Intravenous immunoglobulin (IVIG) in high doses – Fc receptor blockade on phagocytes,
antiidiotypic activity
9.5 Immunosuppresion by antigen
Tolerance induction by oral antigen, limited by the knowledge of the autoantigen, probably tissue
specific.
Studies of oral tolerance induction
Disease
autoantigen
Multiple sclerosis
myelin basic protein
Rheumatoid arthritis
collagen II
Diabetes mellitus I
insulin
Uveitis
retinal S-antigen
9.6 Allergen immunotherapy
Causal therapy of atopic disease - decreased sensitivity of histaminoliberation, increased T
suppressor activity, allergen specific CD8+ T cells, decreased tissue CD4+ T cells, increased IFN
gamma production, Fc epsilon II suppression, decrease eosinophil tissue recruitment and
activation
9.7 Cytokine, cell membrane antigen manipulation
Soluble cytokine receptor represent endogenous homeostatic mechanism, at high dose can block
IL function and modify the disease, monoclonal Ab against membrane molecule can block the
cell population and function.
Monoclonal ab as immunosupression
Anti CD3
renal, heart graft rejection
Anti CD4
clinical trials of rheumatoid arthritis (RA)
CTLA4-Ig
murine lupus
anti CD25
clinical trials RA
anti-CD40L
murine lupus
anti-IL-1
clinical trials RA
anti-CD20, (rituximab) chimeric antibody - human Fc part combined with mouse variable
domains - trials in malignant lymphoma
anti-CD52 (CAMPATH-1) CDw52 exprimed on T, B cells, clinical trials BCL
anti-IgE (rhuMAb-E25) asthma, allergy
anti IL-4, IL-5
asthma
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9.8 Anti-inflammatory therapy
Nnonsteroidal anti-inflammatory drugs, cyklooxygenase inhibitors, leukotriene antagonists
antihistamines, proinflammatory cytokines inhibition- IL-1Ra (rheumatoid arthritis), anti TNF
Plasmapheresis
9.9 Gene therapy for immunodeficiency diseases
Gene therapy is the process by which exogenous genetic material is transferred into somatic cells
to correct an inherited or acquired gene defect or to introduce a new function or property into
cells. The first human protocol - patients with ADA deficiency in 1990 at NIH
Gene delivery system - Viral vectors, non viral or viral-assisted techniques
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