TRANSPLANTATION AND GRAFT FREGECTUON
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TRANSPLANTATION AND GRAFT REJECTION
 An aggressive immune response by the recipient, unless the transplant is
between monozygotic twins.
 Determined by :
 the genetic disparity between the donor and recipient,
 the immune status of the host and the nature of the tissue
transplanted
 The most important genetic determinant is the difference between donor
and recipient HLA proteins
 Compatibility at all HLA loci
 Decreases acute rejection,
 Improves graft survival,
 Allows the use of less intense immunosuppressive protocols.
Organ
transplantation
complications
Rejection
Genetic disparity.
CD8 & macrophage mediate
most of the rejection
-swelling & pain over the
allograft
GVHR
-Allografted immune competent
tissue( e. g b.m) recognises recipient
as foreign tissue. → CMI
damage to the recipient
- Skin rash, diarrhea,& jaundice
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 Acute cellular rejection is the most common form of graft rejection.
 Chronic allograft failure (chronic rejection) is a major cause of graft loss.
Investigations to avoid rejection
1. HLA typing
2. Anti-HLA antibody screening
3. Donor-recipient cross-matching: a functional assay that directly tests
whether serum from a recipient (which potentially contains anti-donor
antibodies) is able to bind and/or kill donor lymphocytes. Done
immediately prior to transplantation. A positive cross-match is a
contraindication to transplantation because of the risk of hyperacute
rejection.
4. C4d staining: useful in the early diagnosis of vascular rejection.
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COMPLICATIONS OF TRANSPLANT IMMUNOSUPPRESSION
1. infection : opportunistic infections:- CMV: ganciclovir
-Pneumocystis: trimethoprim
-Immunization with killed vaccines is appropriate although the immune
response may be curtailed because of immune suppression. Live
vaccines should not be given
2. malignancy: because T-cell suppression
failure to control viral
infections
-Epstein-Barr virus
lymphoma
-human herpesvirus 8
Kaposi's sarcoma
-human papillomavirus
skin tumours
-A small increase in the incidence of common cancers such as lung,
breast or colon cancer.
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