Monocytes overcome lymphocyte dysfunction in injured adults with elevated Candida antigen titers

Severely injured adults with elevated Candida antigen titers have increased mortality from sepsis, in part because of known neutrophil (PMN) dysfunction. Since PMN function is modulated by monocytes and lymphocytes, this study was undertaken to determine the ability of monocytes and lymphocytes isolated from injured adults with elevated Candida antigen titers to activate the anticandidal function of normal PMNs.

Lymphocytes with or without monocytes, isolated from 18 injured adults with elevated titers, were cultured in the presence or absence of heat-killed Candida albicans for 48 hours. Culture supernatants were harvested, diluted 1:40, 1:160, and 1:640, and tested for the ability to stimulate the anticandidal function of normal PMNs using an 3H-glucose incorporation assay. Monocytes and lymphocytes isolated from nine volunteers were studied for comparison.

Supernatants of lymphocytes from healthy volunteers that were cultured with heat-killed C. albicans significantly augmented normal PMN anticandidal function. Supernatants of lymphocytes from injured adults with elevated titers that were cultured with heat-killed C. albicans did not significantly augment normal PMN anticandidal function. Supernatants of monocytes or lymphocytes from both groups of patients were able to upregulate PMN anticandidal function.

Lymphocytes from injured adults with elevated Candida antigen titers are defective in their ability to stimulate PMN anticandidal function. Monocytes from these patients can respond to Candida exposure and overcome the lymphocyte functional defect seen in injured patients with elevated titers.