Anti-idiotypic antibodies in patients with different clinical forms of paracoccidioidomycosis

Paracoccidioidomycosis (PCM) is the most prevalent systemic mycosis in Lati n America. Patients with PCM show a wide spectrum of clinical and pathologi cal manifestations depending on both host and pathogen factors. Two clinica l forms of the disease are recognized: the acute or juvenile form and the c hronic or adult form. The major antigenic component of the parasite is a gl ycoprotein of 43 kDa (gp43). All patient sera present antibodies against gp 43 (anti-gp43) and, as demonstrated before by our group, spontaneous anti-i diotypic (anti-Id) antibodies (Ab2) can be detected in patient sera with hi gh titers of anti-gp43. Since it has been postulated that anti-Id antibodie s may have a modulating function, we decided to purify and characterize ant i-Id antibodies in this system. The possible correlation of Ab2 titers with different clinical forms of disease was also verified. Results showed that purified human anti-Id antibodies (human Ab2) recognized specifically the idiotype of some murine monoclonal anti-gp43 (17c and 3e) but not others (4 0.d7, 27a, and 8a). Spontaneous anti-Id antibodies were found in all clinic al forms of disease. The majority of patients (88%, n = 8) with the acute f orm of PCM had high titers of Ab2. However, among patients with the multifo cal chronic form of the disease, only 29% (n = 14) had high titers of Ab2; 70% (n = 10) of patients with the unifocal chronic form had low titers of A b2. A correlation between Ab2 titers and anti-gp43 titers was observed befo re and during antimycotic treatment. Our results suggest that titers of ant i-Id antibodies correlate with the severity of PCM in humans.