BASIC IMMUNOLOGY IN TRANSPLANTATION -OR IMMUNOLOGY FOR DUMMIES

Immunology is the study of immune system of the body. The immune system is responsible for the protection of the body against “foreign invaders” such as bacteria or viruses. It also is responsible for the process of rejection of an organ after transplantation. This is because the immune system does not recognize the organ as “self” and therefore wants to destroy it. The long term success of any organ transplant is dependent on adequately decreasing the effectiveness of the immune system so that the transplant can co-exist within the recipient and perform its function and keep the person alive.

The immune system has a series of immune cells that work together to protect the body from “foreign invaders”. There are two main types of immune cells-

a) T cells – that recognize the “foreign invader” with the help of a receptor on its surface, which then starts off a series of chemical reactions that stimulate other T cells to destroy the invader.
b) B cells – that produce a protein called an antibody that then destroys the invading cells.

Multiple other cells, such as the platelets work in tandem with the cells in the immune system to help in the fight as well.

There are pre-formed antibodies such as those associated with the different blood groups that also can cause severe rejection if the blood groups are not adequately matched prior to the transplant procedure. There are four major blood types:

Type A
Type B
Type AB
Type O

The recipient with type A can accept an organ from a donor who is type A or type O. This is because the type A blood group person has antibodies to type B, called anti-B antibodies.
Similarly, type B recipient can accept an organ from type B or type O, since he has anti-A antibodies
Type O can receive an organ from type O only, since he has antibodies to both type A and type B.
Type AB is also called the universal recipient, can receive organs from types A, B, O or AB.