Circulating immune complexes in patients with Candida albicans infections

The existence of circulating immune complexes in patients with candidiasis has been suggested but not confirmed. In this study we have used four immune complex screening techniques (direct nephelometry, Clq binding assay, PEG-IgG assay and PEG-C4 assay) and an immune complex score compiled from results of the individual tests to establish that elevated levels of immune complexes do exist in a series of 11 patients with systemic candidiasis as compared with a group of 18 normal controls. Isolation and characterization of high molecular weight fractions from the sera of five patients with candidiasis and further purification by affinity chromatography on Sepharose 4B-protein A substantiated the presence of anti-Candida antibody and/or Candida antigen in at least three of them. The presence of complement components and IgG in these fractions further supported the existence of immune complexes containing microbial antigen and antibody.