Levels of specific antigen (gp43), specific antibodies, and antigen-anti body complexes in saliva and serum of paracoccidioidomycosis patients

The present study analyses human immunoglobulin G (IgG) antibodies directed against the Paracoccidioides brasiliensis exoantigen, gp43, as well as the presence of gp43-IgG immune complexes (ICs) in 31 samples of saliva and se rum from 19 patients with paracoccidioidomycosis (PCM) and 12 normal donors . Additional analysis of secretory IgA (sIgA) was performed on the same sal iva samples. Consistent with previous findings, a significant increased spe cific IgG level was observed in PCM patients' saliva and serum (P<0.05). Th e analysis of serum gp43 and gp43-IgG IC demonstrated a higher level in pat ients with PCM (P<0.05); however, this difference was not statistically sig nificant with regard to gp43 and gp43-IgG in saliva when compared to the he althy donors. A high level of sIgA in saliva of PCM patients compared to th at of normal donors was also observed (P<0.05). Patients exhibiting low lev els of serum IgG but with high titres of IC were observed, thus strengtheni ng the idea of the necessity to use more than one marker for diagnosis and treatment monitoring of PCM. This is the first report of sIgA in PCM patien ts' saliva and may be indicative of a protective role in neutralizing antig ens on mucosal surfaces.