Immunosuppressive effect of paracoccidioidomycosis sera on the proliferative response of normal mononuclear cells. Identification of a Paracoccidioides brasiliensis 34-kDa polypeptide in circulating immune complexes

Expression of complement receptor type 1 (CR1) on erythrocytes of paracoccidiodomycosis patients

Complement receptor type 1 (CR1) is a membrane glycoprotein that acts as a receptor for the C3b, iC3b and C4b fragments of complement. In primates, one function of erythrocytes is to promote safe clearance of immunocomplexes (IC) from the circulation through CR1. Theoretically, in diseases characterized by high levels of circulating IC, an erythrocyte CR1 (CR1/E) deficiency may favor IC deposition in tissues or facilitate inappropriate activation of leukocytes in the circulation. Depression of the cell immune response occurs in paracoccidioidomycosis (PCM), especially in the more severe cases, and is frequently associated with high serum IC levels. In the present study we quantified the number of CR1/E in patients with the acute and chronic forms of PCM before and after treatment and correlated it with serum IC levels and CD4+ and CD8+ T cell concentration in the peripheral blood of these patients. Patients with PCM, particularly those with active disease and who had received treatment for shorter periods of time, had low numbers of CR1/E. In addition, an increase in serum IC concentration and a reduction in the CD4+/CD8+ T cell ratio were observed. After treatment there was a significant increase in mean CR1/E number and a reduction in serum IC levels. In patients with the chronic form of the disease the CD4+/CD8+ T cell ratio tended to increase after treatment and was associated with increased CR1/E levels. These results suggest that the reduction in CR1/E observed in patients is a phenomenon acquired with the disease and that CR1 could play a role in the pathogenesis of PCM.

Pulmonary paracoccidioidomycosis misdiagnosed as Pneumocystis pneumonia in an immunocompromised host

Yeast cells of Paracoccidioides brasiliensis can resemble the cysts of Pneumocystis carinii in smears stained with Grocott's modification of the Gomori methanamine silver stain. Furthermore, P. brasiliensis can cross-react in material stained with a widely used P. carinii immunofluorescent stain which uses monoclonal antibodies. The need to differentiate P. brasiliensis and P. carinii will become more important as the increasing incidence of immunosuppression results in the reactivation of latent P. brasiliensis infections.