Modulation of the cell-mediated immune response in kala-azar and post-kala-azar dermal leishmaniasis in relation to chemotherapy.

Cell-mediated immune (CMI) response and the concurrent clinical events were studied longitudinally before, during and after treatment in 24 kala-azar (KA) and ten post-kala-azar dermal leishmaniasis (PKADL) patients for a period of six months. The status of specific CMI response was estimated by in vitro tests, viz. lymphocyte transformation and leucocyte migration inhibition in response to L. donovani antigen. The generalized CMI response was assessed by lymphocyte transformation in the presence of mitogen (phytohaemagglutinin) and quantitation of the circulatory T-lymphocyte population. To measure the drug response, the extent of clinical improvement following treatment was used as a yardstick. The results showed that suppression of the CMI response was both specific and generalized in nature during the active stage of KA; but in PKADL, unlike in KA, suppression of the CMI response was found to be associated only at the specific level. With administration of the drug (sodium antimony gluconate), the immunosuppression was gradually eliminated with concomitant clinical improvement in both KA and PKADL patients, although the latter took a longer period of time and a larger amount of drugs compared to the former.