Serological and immunohistological studies on lepromatous leprosy.

Sera of patients with lepromatous leprosy were studied for the presence of a variety of antibodies and immune complexes (IC). The frequencies of heterophile, Hanganutziu-Deicher and Forssman antibodies were 61 and 43%, respectively, which were significantly higher than those in other diseases. The frequency of antibodies to cardiolipin was 89% and the frequency of rheumatoid factor was 34%. Circulating IC were demonstrated in 54% of the patients' sera by Raji-cell test and in 43% by anti-antibody inhibition test. Analyses of immunoglobulin classes of IC revealed that IgG was predominant in IC of patients with lepra reaction (LR) and IgM in patients without LR. Immune deposits were found in and between cells of dermis in skin biopsy specimens of patients with LR.