Cerebrospinal fluid Histoplasma antibodies in central nervous system histoplasmosis.

We have evaluated the Histoplasma antibody response in the cerebrospinal fluid (CSF) in nine patients with central nervous system histoplasmosis and 98 controls. While the CSF Histoplasma antibody response identified eight of the nine patients, CSF cultures were positive in only two. Of controls with histoplasmosis but without meningitis (13 patients), or without histoplasmosis (85 patients), elevated CSF antibodies were detected by complement fixation in seven, by IgG radioimmunoassay in 17, and by IgM radioimmunoassay in five. Measurement of the CSF Histoplasma antibody response appears useful for identifying meningitis in patients with histoplasmosis, although cross-reactions occur in half of patients with other forms of chronic fungal meningitis. Patients with these other infections can usually be identified by tests for CSF Coccidioides antibodies, or cryptococcal antigens.