Delayed hypersensitivity tests with Mycobacterium leprae purified protein derivative.

Skin tests were conducted on 3 lepromatous, 3 dimorphous and 6 tuberculoid leprosy patients and 3 others not suffering from leprosy with lepromin, purified protein derivative from M. leprae of armadillo origin and tuberculin. Results show that a delayed hypersensitivity reaction could be produced with PPD in 72 hours on all Mitsuda positive cases, with one anomalous exception, without cross reaction to tuberculin. The results were promising from the point of view of substituting lepromin with PPD in usual tests.