Anais do Congresso Paranaense de Microbiologia
IV Congress of Microbiology in Paraná

Paracoccidioidomycosis (PCM) is the most important systemic mycosis in today’s Latin-America, caused by thermally dimorphic fungi of the Paracoccidioides species complex, mostly P. brasiliensis and, more rarely, P. lutzii. Eighty percent of the cases are registered in Brazil, mainly in the southern, southeastern and midwestern states. With such a large geographical distribution, it is expected to come across different species and strains. P. lutzii has substantial differences when compared to the P. brasiliensis strains, especially when it comes to its antigens: strain LDR2 does not produce 43 kDa glycoprotein (gp43), one of the main Paracoccidioides immunogens. In this context, it is important to identify the species causing PCM in each region. Considering the difficulty of isolating the fungus from the environment or from patients’ biological samples, serological reactivity is often employed. When analyzing strains and sera from patients living in the northern cities of Paraná (mainly Londrina), past research pointed to the potential differences in comparison to other regions of Brazil, suggesting higher number of cases caused by P. brasiliensis than P. lutzii. This research aimed to compare sera reactivity to P. brasiliensis and P. lutzii antigens from patients with PCM living in the west region of Paraná, Brazil. To do so, an indirect enzyme-linked immunosorbent assay (ELISA) was performed using three 96-well polystyrene plates coated with cell-free antigens (CFA) from different Paracoccidioides strains: P. brasiliensis B339 (PS3), P. brasiliensis Pb18 (S1) and P. lutzii LDR2. Twenty-four sera from patients previously diagnosed with PCM, from people living in Cascavel or Foz do Iguaçu regions, were used at 1/200 dilution. D'Agostino & Pearson omnibus normality test was done, followed by ANOVA with Tukey's multiple comparisons test, considered significant as p-value < 0.05 (Graphpad Prism 6.01 software). ELISA results showed greater reactivity with CFAs from P. brasiliensis B339 (PS3) or P. brasiliensis Pb18 (S1) than with P. lutzii LDR2 (p<0,0001). In conclusion, antibody reactivity of PCM patients’ sera from Cascavel and Foz do Iguaçu was lower with P. lutzii antigens, suggesting the predominance of P. brasiliensis as the causative agent of PCM in the western region of Paraná, as already demonstrated in the northern region (Londrina). Current data points to the importance of using antigens from P. brasiliensis PS3 or S1 for serological PCM diagnosis in these regions of the Paraná state.