People who are born without enough number of T cells and B cells are highly prone to infections. The diseases generated by the deficiency of T cells or B cells are called immuno deficiency diseases. This is a most serious cause .in severe case it is known by name severe combined immuno deficiency . in which both T cells and B cells are absent and such patients more susceptible to diseases. The most common immuno deficiency syndrome is AIDS (acquired immune deficiency syndrome.). it is caused by HIV virus . ie, human immuno virus. The characteristic symbol of aids is that the reduction of T cells in body .

Immuno deficiency test –ELISA

Elisa is an immuno chemical tst used to find antibodies and antigen in the body . the technique was developed by Engwall and Pemlmann .Now as days Elisa is used as a test to detect the antibodies produced by body against HIV. The virus which cause aids in man. Elisa test can be used for finding infections such as rubella virus, hepatitis B.,etc. the basic principle in Elisa test is antigen antibody reaction.