No abstract

Between 1982 and 1986 we have had the chance to study 21 patients with pemphigus foliaceus of the 'fogo selvagem' type. The patients came from El Bagre and Nechi, rural areas of Colombia with some gold mining. This is the first outbreak of South American pemphigus foliaceus reported in Colombia. The majority of the patients were mestizo men, who worked as farmers or miners or both, with an average age of 44. Five patients were relatives. Eleven patients (52%) had mild disease, three (14%) moderate disease and seven (33%) severe disease. During hospitalization, three patients died due to complications or as a result of immunosuppressive treatment. Of the remaining 18 patients, 10 were in remission with treatment, one was in remission without treatment, while no information was available on the remaining seven.

The precise diagnosis of paracoccidioidomycosis, in most cases, is established by direct methods and indirect immunological tests. The latter method is reliant on the identification of the host's humoral responses, which are usually impaired or absent in patients with severe juvenile forms of the disease and in immunocompromised patients. Determining disease activity or assessing treatment responses by measuring antibody levels is difficult, since antibody titer may remain elevated or persist at stationary levels, even in the presence of clinical improvement. Consequently, there is a need for alternative tests aimed at the identification of circulating antigens. A modification of the standard hybridoma production method was used to raise a panel of murine monoclonal antibodies (MAbs) against the yeast form of Paracoccidioides brasiliensis. Of these, MAb P1B, directed against an 87-kDa determinant, was used to develop an inhibition ELISA (inh-ELISA) capable of detecting as little as 5.8 ng of circulating antigen per ml of serum. Sera from 46 patients with paracoccidioidomycosis or other mycoses and sera from healthy individuals were evaluated by the inh-ELISA; overall sensitivity was 80.4% (37 of 46 paracoccidioidomycosis patients tested positive), and specificity compared with that of normal controls from areas of endemicity was 81.4%. The inh-ELISA detected circulating antigen in 100% of patients with the acute form of paracoccidioidomycosis and in 83.3 and 60% of patients with the chronic multifocal and unifocal forms of paracoccidioidomycosis according to the patients' clinical presentation. These results indicate that the inh-ELISA with MAb P1B is effective in the detection of circulating antigen and that this test may be useful for monitoring responses to treatment and establishing disease prognoses.

Forty-six Paracoccidioidomycosis patients were studied with emphasis on lung pathology. It was found that the greatest clinical involvement of the reticuloendothelial system occurred in younger individuals. On the other hand, the frequency of tegumentary lesions was low in young patients and increased with age. Lung involvement was nearly always demonstrated when searched for and showed no relationship to the patient's age. In the young patients the disease was acute while in the older individuals its course was chronic. The findings from this study permitted formulation of a model for the pathogenesis of paracoccidioidomycosis in which the respiratory tract is accepted as the primary site of infection. Based on this model, a classification of the various forms of the entity is proposed.

Histoplasmosis is an important systemic fungal infection, particularly among immunocompromised individuals living or travelling in areas of endemicity, who, without antifungal therapy, may develop a progressive disseminated fatal infection. For such patients, the detection of antibody responses by immunodiffusion or complement fixation test is of limited use. In contrast, the detection of Histoplasma capsulatum circulating antigens may provide a more practical approach to the rapid diagnosis of the disease. Accordingly, an inhibition enzyme-linked immunosorbent assay (ELISA) for the detection of a 69-to 70-kDa H. capsulatumspecific determinant and incorporating a species-specific murine monoclonal antibody was developed. With sera from patients with different forms of the disease (n ‫؍‬ 35), the overall sensitivity of the test was found to be 71.4%, while the specificity was found to be 98% with normal human sera from areas of endemicity (n ‫؍‬ 44) and 85.4% with sera from patients with other chronic fungal or bacterial infections (n ‫؍‬ 48). This novel, highly specific ELISA provides a significant addition to the existing diagnostic tests for the detection of histoplasmosis.