Consequences of smallpox vaccination in leprosy patients.

This study illustrates the consequences of smallpox revaccination in 45 lepromatous, 28 tuberculoid, and 47 normal individuals. Results obtained with intradermal inoculations indicated that the patients with leprosy were associated with a relative anergy against the vaccinia virus, the anergy being minimal in the tuberculoid leprosy but marked in the cases with lepromatous leprosy. Major vaccinial reactions were observed more often in patients with lepromatous leprosy than in the controls or patients with tuberculoid leprosy. Furthermore in a patient with lepromatous leprosy, vaccinia necrosum also developed. The smallpox vaccination with live virus also appeared as a provocative factor for the precipitation of lepra reaction in the lepromatous leprosy cases. After 3 weeks of vaccination, the frequency of the specific humoral antibody response was the same in the tuberculoid patients and controls while it was higher in the cases with lepromatous leprosy. The prevaccination titer of total hemagglutination inhibition antibody was significantly higher in the lepromatous leprosy cases. However, the postvaccinial, humoral antibody response of the lepromatous patients was of the same magnitude as that observed in the normal individuals, and it was mainly due to a 2-mercaptoethanol-resistant antibody.