Reversal reaction in lepromatous patients induced by a vaccine containing killed ICRC bacilli--a report of five cases.

Clinico-pathological features of five cases of lepromatous leprosy exhibiting "reversal" reaction with upgrading of lesions following vaccination with ICRC vaccine have been described. Two patients also developed ENL. Associated with the "reversal" reaction, the patients exhibited lepromin conversion. No evidence of fresh nerve lesions was observed in any patient. Besides lepromin conversion, occurrence of "reversal" reaction is yet another evidence of immunogenicity of the ICRC vaccine.