Antibodies to Candida albicans in IgA-deficient humans

Titers of serum antibody to Candida albicans were studied in 111 IgA-deficient subjects by the passive hemagglutination method. Circulating antibodies to C. albicans (mean titer, 1:7) were found in only 7.3% of the 111 subjects, as compared with 80% of 137 controls (mean titer, 1:16). However, two IgA-deficient patients with systemic candidiasis were positive for these antibodies (mean titer, 1:64). Indirect immunofluorescence tests indicated that the antibody response in IgA-deficient subjects to superficial or deep-seated infection with C. albicans consists mainly of immunoglobulins of the IgG rather than of the IgM class.