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Tissue Typing. Everyone has several antigens located on the surface of his/her leukocytes:. One particular group of these antigens is called the HLA (Human Leukocyte Antigens). The HLA. Is responsible for stimulating the immune response to recognize tissue as self versus non-self.

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Everyone has several antigens located on the surface of his her leukocytes
Everyone has several antigens located on the surface of his/her leukocytes:

  • One particular group of these antigens is called the HLA (Human Leukocyte Antigens).


The hla
The HLA his/her leukocytes:

  • Is responsible for stimulating the immune response to recognize tissue as self versus non-self.

  • Is controlled by a set of genes located next to each other on chromosome 6 called the Major Histocompatibility Complex (MHC).


Tissue typing


Tissue typing


There are two main classes of hla antigens
There are two main classes of HLA antigens: the recipient, the more likely that the recipient’s body will not reject the transplant.

  • Class I (HLA-A, HLA-B, and HLA-Cw)

  • Class II (HLA-DR, HLA-DQ, and HLA-DP)


Tissue typing


Tissue typing


Tissue typing


Tissue typing


Tissue typing


Tissue typing


Tissue typing

  • By analyzing which six of these HLA-antigens both the donor and recipient have, scientists are able to determine the closeness of tissue matching.

    • A six-antigen match is the best compatibility between a donor and recipient.

      • This match occurs 25% of the time between siblings who have the same mother and father.


Hla typing techniques
HLA Typing Techniques and recipient have, scientists are able to determine the closeness of tissue matching.

  • Traditionally, HLA typing was done using serological techniques:

    • Blood from the patient was mixed with serum containing known antibodies to determine which antigens were present.

  • HLA typing now is predominantly done using molecular techniques:

    • Patient’s DNA is isolated.

    • PCR is used to amplify specific HLA genes.

    • Genes are sequenced to determine which alleles are present.


Tissue typing

  • Once the donor and recipient have been tested for tissue compatibility, the next step is an Antibody Screening (also calleda Panel Reactive Antibody or PRA).

    • A small amount of the organ recipient’s serum is mixed with cells from 60 different individuals (each test is done separately).


Purpose of antibody screening
Purpose of Antibody Screening compatibility, the next step is an

  • Scientists can determine how many different HLA antibodies a patient has in his/her blood.

    • If a patient reacts with 30/60 cells, he/she is said to have 50 Percent Reactive Antibody (also known as PRA).

    • The lower a person’s PRA, the less likely he/she is to reject a transplant.


Crossmatch test
Crossmatch Test compatibility, the next step is an

  • After tissue typing and antibody screening are complete and a potential donor has been identified, the final test is called a crossmatch test.

    • Crossmatch Test: A small amount of the potential donor’s white cells is mixed with a small amount of the recipient’s serum.

      • By exposing the donor’s HLA to the recipient’s serum, scientists can determine if the recipient has antibodies to any of the donor’s HLA.


Tissue typing

  • Positive Crossmatch: A reaction between the donor’s and recipient’s samples occurs.

    • Indicates that the recipient’s body will likely reject the implanted kidney.

    • Indicates the transplant cannot be performed.

  • Negative Crossmatch: No reaction between the donor’s and recipient’s samples occurs.

    • Indicates that the recipient’s body will most likely not reject the implanted kidney.

    • Indicates the transplant can be performed.