Circulating immune complexes and anti-IgG antibodies in mucocutaneous leishmaniasis.

Circulating immune complexes (CIC), anti-IgG, anti-DNA, and anti-collagen autoantibodies (Ab) were investigated in sera from patients with South American leishmaniasis. No significant levels of anti-DNA or anti-collagen autoantibodies were observed. Only a few patients with cutaneous leishmaniasis or with only one mucocutaneous lesion showed values for CIC and anti-IgG Ab higher than those in the control group. In contrast, both CIC and anti-IgG Ab were demonstrated in most patients with several lesions due to mucocutaneous leishmaniasis (MMC). Moreover, a close correlation was noticed between the detection of CIC and anti-IgG Ab in MMC patients. This relationship suggested that part of the detected CIC could have been formed by IgG-anti-IgG complexes. The involvement of these immunopathologically active substances in the clinical evolution of mucocutaneous leishmaniasis is discussed.