CIEP and ELISA for the serological diagnosis of paracoccidioidomycosis in patients infected with HIV. Serum samples from patients with en- demic paracoccidioidomycosis and not infected with HIV

In a vast area of South America, paracoccidioidomycosis is the fourth most common systemic fungal infection among patients with human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS). Opportunistic infection with Paracoccidioides brasiliensis is generally disseminated among patients with a low CD4 cell count, involving the lungs, tegument, lymph nodes, monocyte-macrophage system and other tissues (Silva-Vergara et al. 2003, Morejón et al. 2009). This clinical picture must be differentiated from other opportunistic infections, particularly those involving mycobacteria and histoplasmosis. The detection of serum anti-P. brasiliensis antibodies is a rapid, non-invasive and efficient method for the laboratory diagnosis of endemic paracoccidioidomycosis not associated with HIV/AIDS. The recommended serological tests are double immunodiffusion (DID), counterimmunoelectrophoresis (CIEP) and enzyme linked immunosorbent assay (ELISA) (Shikanai-Yasuda et al. 2006). With the use of appropriate antigens and procedures, these tests reach a sensitivity of 90% or more and high specificity (Mendes-Giannini et al. 1994). The titration of anti-P. brasiliensis antibodies is important for the laboratory diagnosis and follow up of paracoccidioidomycosis. Patients with active disease usually have high antibody levels, which decline with antifungal therapy and clinical recovery (Del Negro et al. 2000). Immunosuppressed patients with opportunistic paracoccidioidomycosis may have a reduced specific humoral immune response. A significant proportion of false-negative results of serological tests for the detection of antibodies against P. brasiliensis have been observed in patients with AIDS-associated paracoccidioidomycosis (Marques et al. 2000). Few cases of this coinfection have been reported and they are distributed among various medical services with no uniformity regarding the serological tests (Goldani & Sugar 1995). Thus, the objective of the present study was to compare the performance of DID, CIEP and ELISA for the serological diagnosis of paracoccidioidomycosis in patients infected with HIV. Serum samples from patients with endemic paracoccidioidomycosis and not infected with HIV were subjected to the same tests and the results obtained were used as reference for the habitual serological response to this fungal disease.