Antibody-Mediated Rejection:
Prevention, Pathophysiology,Treatment,
Brenda Muth, RN, MS, ACNP
Transplant Nephrology
and Desensitization
Objectives
Define rejection
Acute vs Chronic
Clinical vs subclinical rejection
AMR, ACR, mixed
Discuss prevention of AMR
Review immunologic components involved in AMR
Review diagnosis of acute AMR
Examine treatment options
Current therapies
Novel treatment including off-label use
UW protocols for AMR treatment
Definitions
AMR
Graft rejection caused by Ab directed against
HLA molecules, ABO antigens or endothelial
cell antigens
Clinical Rejection
Biopsy confirmed with associated graft
dysfunction
Subclinical Rejection
Histological changes specific for acute
rejection on protocol biopsy w/o graft
dysfunction
Definitions
• Hyperacute Rejection
– Due to preformed Ab
• Early AMR
– Due to amnestic Ab response
• Late AMR
– Due to de novo DSA production
• Chronic AMR
– Recall secondary DSA response
• Mixed rejection
• Accomodation
– Resistance to injury in presence of Ab
Lymphocytes
Myeloid
Stem cell
Lymphoid
Stem Cell
SC
Lymphoblast
T
PC
B
NK
CD
20
The sequence of letters & numbers
identify which HLA gene it is & it’s
location
HLA-DQB3*0101 (DR52)
Gene
Specific HLA protein
Allele
(alternate form of the same gene)
Pathophysiology of AMR
Donor
Organ
Capillary
Endothelial
cell
C1 complex
4
Damaged
Cell
Releases
platelet
aggregation
factors,
cytokines
Formation
of
Antigen-Ab
complex

C4

C4b  C4d
Endothelial
cell
necrosis
C4d is by-product and marker
of complement activation
Schwartz, NEJM 2010
Prognosis of AMR
• Vasculopathy
• Fibrosis
• Loss of graft function/graft loss
Diagnostic Criteria for Kidney AMR
Must have at least 2 of the following
• Presence of anti-donor antibodies
• C4d staining
– C4d1:
– C4d2:
– C4d3:
Minimal C4d stain/detection: 1<10%
Focal C4d stain/positive: 10–50%
Diffuse C4d stain/positive: >50%
• Morphologic evidence of tissue injury
– Capillary and or glomerular inflammation (ptc/g >0)
and/or thromboses
• Graft dysfunction
Diagnostic criteria for Pancreas
AMR
• Acute AMR: (all 3 criteria)
– Circulating DSA
– morphologic evidence of microvascular
tissue injury
– C4d staining of interacinar capillaries
• Suspicious for AMR
– 2 of 3 criteria
Drachenberg et all, AJT 2011(9)
Consensus Statement
for Heart AMR
• Based on pathology:
– Histology
•
•
•
•
•
Endothelial activation
Intravascular macrophages
Neutrophilic infiltrates
Capillary destruction
Interstitial edema, hemorrhage
– Immunopathology
• May include DSA, graft dysfunction
Kobashigawa et al, Journal of Heart and Lung Tx, 2011 (3).
Diagnostic Criteria for Liver AMR
• Lack of clear criteria for diagnosis.
• May include:
– Positive C4d staining of sinusoidal
endothelium
– Proliferation of small bile ducts
– Sinusoidal accumulation of neutrophils
– cholestasis
Kozlowski, et al, Liver Transplantation, 2011
Diagnostic Criteria for Lung AMR
• Difficult to diagnose
• May be determined by prominence of
B cells and plasma cells in
inflammatory infiltrate, endothelialitis
and small airway inflammation
Takemoto et al, AJT, 2004
Antibody mediated rejection
Peritubular capillaritis and focal interstitial hemorrhage
Nickeleit, Neph Dial and Transplant 18: 2232-2239, 2003
Peritubular capillary
Immunofluorescent
Staining
for C4d
Peritubular capillary
Immunohistochemistry
staining
for C4d.
Nickeleit, Neph Dial and Transplant 18: 2232-2239, 2003
CD
20
AMR Treatment
T
PC
AMR Treatment
•
•
•
•
Suppression of T cell response
Elimination of circulating Ab
Inhibition of Ab
Suppression/Depletion of B cells
Suppression of T-cell Response
Depletional Antilymphocyte Ab (rATG)
• Has multiple anti-T cell Ab specificities, costimulatory pathways,
cell adhesion molecules, cell surface molecules expressed on B
cells and plasma cells.
• Usually used as adjuvant therapy in AMR
• Used for severe or steroid resistant ACR
• FDA approved for Kidney transplant rejection
Steroids
• inhibits IL-1,IL-2, IL-6 production, T-cell proliferation, cytokine
gene transcription & antigen presentation
MPA
• Prevents proliferation of T & B-cells
• FDA approved for kidney
CNI
• Both CsA & Tac inhibit T & B-cell activation and proliferation
• FDA approved for kidney, liver, heart
Singh et al, Transplantation Review, 2009
Samaniego et al, Nature Clinical Practice, 2006
micromedex
Elimination of Circulating Ab
Plasmapheresis
• Fast, effective method of eliminating DSA
• Used in combination with other therapies
• Adverse effects:
– Nonselective removal of proteins, bleeding diatheses, volume
contraction, requires replacement fluid (albumin), allergic reactions, bld
borne pathogens, need HD access
• Dose:
– 1-1.5 total plasma volume QD or QOD (3 to 6 treatments), followed by
maintenance PP
– Decision to stop PP should be based on:
• elimination of donor-directed HLA antibody
• establishment of good graft function
• graft failure
• Cost: ~ $2000.00 per treatment
Apheresis Guidelines
considered a therapeutic option when AMR has been confirmed by Bx
and/or + DSA & immunosuppressive treatment has not been
effective.
Singh et al, Transplantation Review, 2009
Apheresis Guidelines, 2009
Inhibition of Antibody
Immune Globulin
Highly purified IgG from large pools of human plasma diluted in
sterile water +/- glucose, sodium.
Non-FDA labeled use
• Action:
– immunomodulatory effects on T cells, macrophages, cytokine
synthesis, B-cell function & regulatory action on complement system
– Down regulates antibody/blocks HLA Ab from binding to targets
– T & B cell suppression
• Adverse effects:
– Arthralgias, mylagias, HA, HTN, hypotension, MI,
Hypercoagulability, allergic reactions, volume overload, AKI
• Dose:
– T ½ = 3 weeks
– Range 100 mg/kg to 2 gm/kg
– ~ $500.00 for 100mg/kg dose
Singh et al, Transplantation Review, 2009
Micromedex
Suppression/Depletion of B-cells
Rituximab
Genetically engineered chimeric MoAb w/ mouse fused with
human IgG.
• Indication:
– FDA approved for Non-hodgkin’s Lymphoma, rheumatoid
arthritis. Use for AMR is off label.
• Action:
– binds to the CD20 antigen located on pre-B & mature B
lymphocytes: mediates B cell lysis
– Depletes CD19 & CD20 (Chemical splenectomy)
– No effect on plasma cells
• Adverse effects:
– Infusion and hypersensitivity reactions, cytopenias, fever, 
infection risk including association with BK
• Dose
– 375 mg/m2 BSA IV
– Duration of treatment ?
– ~ $650.00
Singh et al, Transplantation Review, 2009
Micromedex
Depletion of Plasma cell
Bortezomib
Reversible proteasome inhibitor
• Indication: FDA approved for multiple
myeloma. Use for AMR is off label.
• Dose: 1.3 to 1.5 mg/m2 IV day 1, 4, 8, 11.
• Adverse effects:
– Neuropathy, plt,  WBC, GI symptoms
• Cost ~$2000 per injection
UW experience:
used in kidney, liver and pancreas AMR
Steroids + PP + IVIG + Bortezomib +/- ATG
Everly et al, Transplantation, 2008
Djamali et al, Clinical Transplants, 2009
Sollinger et al, WTC Abstract 2010
Complement Inhibition
Eculizumb
• Recombinant humanized monoclonal IgG antibody
produced from murine myeloma cells that inhibits the
cleavage of C5
• Indication: PNH, atypical HUS
• Blocks graft injury in presence of DSA, may suppress
plasma cells.
• Adverse effects:
– Risk of neisseiria meningitis, need immunization
• Mayo monitored DSA, B & T flow CM, protocol Bx.
• Dose:
– 600 mg IV injection qw to q2w
– Duration of therapy unknown
– Cost $5000 for 300 mg vial
Monitoring during treatment
• Graft function
• Infection
– Viral, bacterial, fungal
• Bone marrow suppression
– Leukopenia, thrombocytopenia, anemia
• DSA
• Immunosuppression
• Repeat biopsy
Prevention
• Identify who is at risk
– Sensitized
• Current PRA > 20%, Peak PRA > 50%
• Black race, Female, retransplant
– + crossmatch
– Certain disease states (SLE, PSC)
• Caution with minimizing
immunosuppression
• Monitor
– DSAs, Biopsy, organ function
UW Kidney Transplant Rejection Protocols
Suspicious Dex 50 mg IV + taper
IA, IB
Dex 100 mg IV + taper
IIA, IIB, III
Dex 100 + taper + ATG
C4d< 50%
+/Banff I
Early: (<3m)
Dex 50mg + taper + TPE 3 to 5
treatments + IVIG 100 mg/kg after each
TPE
Late: (> 3m)
Dex 50 mg + taper + IVIG 100
mg/kg weekly x 4wks
C4d> 50%
+/Banff I
Early:
Dex 100 mg + taper + TPE 3 to 5
treatments + IVIG 100mg/kg
Late:
Dex 100 mg + taper + IVIG
100mg/kg x 4wks
C4d < 50%
+
Banff II or
III
Dex 100mg/kg + taper + TPE 3 to 5
treatments + IVIG 100mg/kg + either
ATG or Bortezomib
Conclusion
• AMR can occur at any time
• Biopsy confirmed diagosis
• Due to preformed Ab, memory
response or de novo Ab production
• Causes vascular injury & fibrosis 
to  long term graft survival
• Can be recalcitrant to treatment
 risk for infectious complications
after treatment
Thank you!