Studies of Immune Mechanisms in Leprosy

TLDR

Patients were grouped by duration of diaminodiphenylsulfone therapy and their skin‑test responses were compared. Leprosy patients exhibit a generalized depression of delayed hypersensitivity, most pronounced in lepromatous cases, which improves toward normal with long‑term diaminodiphenylsulfone treatment—especially in lepromatous patients—while primary sensitization to picryl chloride remains largely absent and disease‑related factors influence reactivity.

Abstract

Skin tests of delayed hypersensitivity performed on 107 patients with leprosy and 30 controls with six protein antigens and the hapten, picryl chloride, indicated that leprosy is associated with a generalized depression of the delayed allergic inflammatory response. The depression is of greatest severity in patients with lepromatous leprosy and is less among tuberculoid patients. Patients were assigned to groups according to time under therapy with diaminodiphenylsulfone, and the results of skin tests were compared. There was a significant progression toward "normal" reactivity to skin-test antigens in "long-term" as compared with "short-term" treatment groups. This trend was more evident among lepromatous patients; the possible salutary effects of chemotherapy upon skin reactivity were defined less sharply in tuberculoid patients. Attempts to establish primary sensitization to picryl chloride failed in a high percentage of patients with leprosy as compared with controls, regardless of type of disease or stage of convalescence. Factors directly related to the pathologic process itself appear to act, at least in part, as determinants of immunologic reactivity in leprosy.