Altered Ex Vivo Expression of Caspase 8, Caspase 9, and Bcl-2 Is Associated with T-Cell Hyporeactivity in Patients with Paracoccidioidomycosis

To better understand the T-cell hyporesponsiveness of patients with paracoccidioidomycosis, we tested the hypothesis that the T cells were committed to apoptosis. We show here that T cells of patients with paracoc-cidioidomycosis overexpress caspase 9 and caspase 8 but express low Bcl-2 levels and that interleukin-2 was unable to revert the hyporesponsiveness. These data suggest that the T cells would in vivo be driven to a tolerant state and apoptosis. Paracoccidioidomycosis (PCM) is the most prevalent sys-temic mycosis in Latin America, with Brazil contributing the highest number of cases (1). Host resistance to Paracoccid-ioides brasiliensis relies on cell-mediated immune response, predominantly of the Th-l phenotype, and by the ability of the T cells to proliferate in response to fungal antigens and gen-erate effector T cells (1). Several researchers have shown that T cells from patients with disseminated PCM have decreased proliferative responses and production of Th-1 cytokines, such as interleukin-2 (IL-2) and gamma interferon, in response to P