Correlation of in vivo delayed-type hypersensitivity with in vitro lymphocyte transformation in sarcoidosis.

O. P. SHARMA The cardinal immunological defect in sarcoidosis is depression of delayed-type hypersensitivity which is readily demonstrated by skin tests using tuberculin, Candida albicans, or the chemical dinitrochlorobenzene (DNCB). It is also known that in vitro culture of lymphocytes from sarcoidosis patients fail to undergo blastic transformation in response to phytohaemagglutinin (PHA). We have correlated the in vitro lymphocyte transformation to PHA with the in vivo response to DNCB in patients with sarcoidosis and in normal control subjects. There is a close correlation between in vitro and in vivo anergy, suggesting that the latter is due to a defect in cellular antibodies of the lymphocyte series. A series of 21 patients in whom the diagnosis of sarcoidosis was supported by histological confirmation was compared with 17 control subjects who had no evidence of any disorder which might depress immune mechanisms. DNCB sensitization was performed initially with a 10% solution in acetone and tested four weeks later with a 0 1 0% solution. The results of lymphocyte transformation were assessed by the percentage of blast cell transformation demonstrated by May-Grunwald-Giemsa stained smears and also by the uptake of tritiated thymidine (liquid scintillation counting). Fifteen of 21 (71 %) patients with sarcoidosis failed to develop DNCB sensitization which could be induced in 82% of the control subjects. In all but one control up to 90% lymphocytes showed blast formation and mitotic activity, whereas blast formation was under 70% in 19 of 21 (90 %) patients with sarcoidosis. There was a close correlation between the negative in vivo DNCB test and the sluggish in vitro lymphocyte response, both phenomena being noted in 71 % of patients with sarcoidosis but in none of the controls. The ability to accept DNCB sensitization and have responsive lymphocytes was evident in three-quarters of controls and in only 10% of sarcoidosis patients.