Leprosy and tuberculosis. A comparative study with the aid of skin tests with tuberculin, killed BCG, and the Dharmendra lepromin in South African Bantus

The purpose of this study was to acquire information on the immunological relationship between leprosy and tuberculosis, with respect to the theory that tuberculosis protects against leprosy. The results indicated that the late reaction to lepromin, produced in some tuberculin-negative healthy people was slightly intensified and accelerated in patients with tuberculosis and tuberculoid leprosy, which could be explained by the nonspecific Dienes effect. Gross hypersensitivity cannot be ruled out as an explanation. If cross hypersensitivity in our study were identical with cross-immunity, which is not certain, it would mean that BCG has a protective influence against leprosy....