The sensitivity of IgG/IgM by EIA using a cutoff of 10 EU/mL and 20 EU/mL was higher in patients with subacute histoplasmosis (13/13, 100% CI 77.2–100.0; 13/13, 100% CI 77.2–100.0, respectively) and chronic histoplasmosis (3/3, 100% CI 43.9–100.0; 3/3 100% CI 43.9–100.0, respectively) compared to patients with acute histoplasmosis (32/46, 69.5% CI 55.2–80.9; 29/46, 63.0% CI 48.6–75.5, respectively). This evidence concerns the gene CD40LG and histoplasmosis.