MCQ on sex linked graft rejection

Skin transplant was done from sister to brother. After few years, brother to sister skin transplant was done, but rejection occurred. What is this phenomena called as?

a. Schwartzman reaction
b. Theobald smith phenomena
c. Eichwald Silmser effect
d. Schultz Dale phenomena

Answer: c

EICHWALD SILMSER EFFECT also called SEX-LINKED GRAFT REJECTION

• –– While transplants between members of a highly inbred strain of animals are successful, an exception is seen when the donor is a male and the recipient a female.
• –– Such grafts are rejected as the grafted male tissue (XY) will have antigens determined by the Y chromosome which will be absent in the female (XX) recipient.
• –– Grafts from the female to the male will succeed.
• –– This unilateral sex linked histoincompatibility is known as the Eichwald-Silmser effect.
• Sex linked graft rejection is due to Histone demethylase UTY ( = enzyme ) in humans encoded by the UTY gene (it contains “H-Y transplant antigen” present on Y-chromosome of male). This gene encodes a protein containing TETRATRICOPEPTIDE REPEATS, which are involved in “PROTEIN-PROTEIN” INTERACTIONS. This protein is a MINOR HISTOCOMPATIBILITY antigen.
• It may induce graft rejection if male-sibling is donor for female but female to male there is no graft rejection (due to H-Y transplant antigen present on Y-chromosome of male)

In Simple words:- Sex linked graft rejection is:

Sister to Brother transplant = graft accepted; but;
Brother to Sister transplant = graft rejection