Immunotherapy of lepromin-negative borderline leprosy patients with low-dose Convit vaccine as an adjunct to multidrug therapy; a six-year follow-up study in Calcutta.

The present report, which describes management of lepromin-negative borderline leprosy patients with low-dose Convit vaccine, is an extension of our earlier study on the treatment of lepromatous leprosy patients with low-dose Convit vaccine as an adjunct to multidrug therapy (MDT). The test Group I, consisting of 50 lepromin-negative, borderline leprosy patients, were given low-dose Convit vaccine plus MDT. The control group II consisted of 25 lepromin-negative, borderline leprosy patients given BCG vaccination plus MDT and 25 lepromin-negative, borderline leprosy patients given killed Mycobacterium leprae (human) vaccine plus MDT. The control group III consisted of 50 lepromin-positive, borderline leprosy patients not given any immunostimulation but given only MDT. Depending upon the lepromin unresponsiveness, the patients were given one to four inoculations of the various antileprosy vaccines and were followed up every 3 months for 2 years for clinical, bacteriological and immunological outcome. All patients belonging to the test and control groups showed clinical cure and bacteriological negativity within 2 years. However, immunologic potentiation, assessed by lepromin testing and the leukocyte migration inhibition test (LMIT), was better in the test patients receiving low-dose Convit vaccine plus MDT than in the control patients receiving BCG vaccine plus MDT or killed M. leprae vaccine plus MDT or MDT alone. But the capacity of clearance bacteria (CCB) test from the lepromin granuloma showed poor bacterial clearance in the test patients. However, there was no relapse during 6 years of follow up. Two mid-borderline (BB) patients had severe reversal reactions with lagophthalmos and wrist drop during immunotherapy despite being given low-dose Convit vaccine.