Cryptococcus neoformans- and Cryptococcus gattii-specific IgG, IgA and IgM differ among children and adults with and...

Cryptococcus neoformans (Cn) and Cryptococcus gattii (Cg) cause cryptococcosis, a life-threatening systemic mycosis of global distribution affecting mainly immunocompromised adults. Although a humoral response occurs during cryptococcosis, the role of antibody production against this mycosis is not fully understood. We aimed to determine total and specific antibodies against cryptococcal protein antigens in sera from people with and without a diagnosis of cryptococcosis from Colombia. Using ELISA, total and specific levels of immunoglobulin (Ig)G, IgA and IgM were determined in sera from children and adults with (n = 109) and without (n = 119) cryptococcosis. Specific antibodies were those binding Cn- and Cg-protein antigens. In general, the mean of the total IgG production was higher in cryptococcosis patients than in controls (13 942.32 vs. 6459.91 µg/ml), while levels of IgA (488.13 vs. 1564.53 µg/ml) and IgM (775.69 vs. 1014.72 µg/ml) were higher in controls than in cryptococcosis patients (P ≤ .05). In patients with cryptococcosis, total IgG, IgA and IgM levels were higher in HIV + compared with HIV- (P ≤ .05). Specific antibodies tended to be higher in cryptococcosis patients than in controls and in adults than in children, with a positive correlation between antibody reactivity and age. All immunoglobulins were more reactive against Cn-proteins than Cg-proteins. Overall, a positive weak correlation between total and specific antibodies was found, although not always statistically significant. In patients with cryptococcosis from Colombia, the levels of immunoglobulins, total and specific, differ with respect to people without cryptococcosis. Variations in antibody production among adults and children with cryptococcosis and between Cn- and Cg-protein antigens were as well established. Our findings encourage further studies to determine the role of humoral immunity for host defense against cryptococcosis.