Correlation of clinical, histological and immunological features across the leprosy spectrum

The Ridley-Jopling system of classification of the variegated clinical pattern of leprosy is based on the specific cell-mediated immunity observed in the histopathology of skin lesions conforming to a spectrum from TT at one end to LL at the other. In this study a fairly large sample of 90 patients was classified on clinical grounds; the histopathology of the skin lesions was studied blind. There was an overall concordance of 90% between the clinical and histological classifications. In addition, the systemic cell-mediated and humoral immune responses were studied. The in vivo cell-mediated immune response, namely the Mitsuda skin response, mostly conformed to the clinical classification. While the in vitro lymphoproliferative responses to BCG and its sonicate were high, the lymphoproliferative responses to Dharmendra lepromin were surprisingly poor. Humoral responses to 35 kDA protein of M. leprae and PGL-1 were good in most LL, BL patients and tapered off towards TT. IgG antibodies to recombinant ML 65 kDa proteins denoted mycobacterial presence.