CORRELATION OF HISTOPLASMA-CAPSULATUM POLYSACCHARIDE ANTIGEN WITH THE SEVERITY OF INFECTION IN MURINE HISTOPLASMOSIS

We sought to determine if Histoplasma capsulatum polysaccharide antigen (HPA) levels correlate with the extent of infection in murine of histoplasmosis. Separate groups of mice were inoculated intratracheally with varying numbers of H. capsulatum yeast cells. After 1 week, HPA levels and fungal burden (quantitative culture of lung and spleen and histopathologic stain of lung) were determined in lung and spleen, and HPA levels in serum. HPA levels, cultures and histopathological stain results of lung and spleen tissue showed a direct correlation with increasing inoculum size. HPA levels in serum also correlated with the size of inoculum. H. capsulatum antigen in lung correlated with silver stain scores of lung tissue, (R = 0.948, P < 0.001) and with quantitative culture scores of lung, (R = 0.929, P < 0.001). HPA levels in spleen tissue also correlated with spleen culture scores, (R = 0.724, P < 0.001). These results indicate that determination of HPA level in serum and tissue may be a useful test in evaluating the severity of diseases as well as efficacy of antifungal therapy in histoplasmosis.