Cell changes and soluble interleukin-2 receptors (Tac peptide) in leprosy reversal reactions using suction-induced blisters.

The cellular contents and soluble interleukin-2 receptor (IL-2R) [Tac peptide] of skin blisters induced by suction over 7 reversal reaction (RR) patients were examined using immunoperoxidase and ELISA techniques respectively. The helper T activity (CD4+ cells) and helper:suppressor ratio were significantly greater in borderline lepromatous (BL) lesions with RR than in quiescent BL lesions. Interestingly, the intracutaneous levels of Tac peptide were elevated and directly correlated with the increases in CD4+ cells. The systemic administration of corticosteroids revealed a reduction in the numbers of CD4+ cells in the lesions. These results indicate that RRs are manifestations of a spontaneous increase in delayed type hypersensitivity (DTH) and possibly cell mediated immunity (CMI) in leprosy patients. The mechanism of such changes in immunity is of considerable value in understanding reversal reactions and the underlying determinants of DTH and CMI in leprosy and this in turn will have a bearing on the potential for proposed vaccines or immunotherapy.