The in vivo and in vitro effects of levamisole in patients with lepromatous leprosy.

Levamisole, 150 mg daily, was administered on 2 consecutive days per week for 6 weeks to two groups of patients with lepromatous leprosy. Group I was composed of patients who were receiving specific anti-leprosy therapy for varying periods of time and Group II were untreated lepromatous patients. Whereas half the patients in Group I received levamisole and the other half a placebo, those in Group II all received levamisole. Patients in both groups showed a) no clinical improvement, b) no conversion of the lepromin reaction, c) no histological change in skin biopsies, d) conversion of SKSD skin reactions from negative to positive in 20% of patients from each group, and e) unaltered absolute neutrophil counts. Whereas the total lymphocyte counts were unchanged in patients from Group I, 13 patients from Group II showed an increased lymphocyte count of greater than 10%. Lymphocyte transformation and lymphokine production in the second group showed no significant change, although four patients showed some lymphokine production after levamisole therapy. E and EAC rosettes were significantly increased in cases where these were reduced prior to treatment with levamisole-Side effects due to levamisole were not experienced.