Immune studies in oral contraceptive users.

Some of the parameters of immune status-percentage of B and T lymphocyte subpopulation, PHA-induced lymphocyte transformation measured by 3H-thymidine incorporation (PILT) and levels of total haemolytic complement (CH5O) were studied in Indian women from low income group who were using estrogen-progestogen combination pills. There were no differences in percentage of B and T lymphocyte subpopulation or PILT between OC users and the control group. However, CH5O levels were significantly lower in OC users. The depression in circulating complement levels in OC users is intriguing and suggests the possibility that complement system and circulating immune complexes may be altered in OC users.