Analysis and function of T and B cells subpopulations in sarcoidosis.

Various technical procedure were applied to the purification of T and B lymphocytes subpopulation in sarcoidosis. Patients were selected according to the presence of a characterized deficit in cell-mediated immune functions. These purified lymphocytes populations were further analysed for their ability to release lymphokines in the presence of Con-A-sepharose or specific antigens. Among these factors, MIF, LIF and mitogenic factor (MF) were looked for. For the determination of MIF and LIF, a newly elaborated technique was deviced which allows a semi-quantitative approach of the lymphokine production. The following results were obtained: A decrease in the absolute number of T lymphocytes was observed among all our patients, and a increase in the number of Ig producing cells. A rather large percent (15 to 40%) of null cells which were carrying characteristic features of quiescent, non activable monocytes. The ability of T lymphocytes to release lymphokines was impaired in the presence of these monocytes but could be restored to normal levels when cells were removed. The results suggest that T cell function might be impaired, in sarcoidosis, by a non identified monocytes abnormal behaviour.