Brasiliensis Antibodies Research Articles

Severe acute paracoccidioidomycosis in children

This report describes clinical and immunologic features of five illustrative cases of paracoccidioidomycosis in previously healthy children. All had disseminated disease and two of them died despite treatment. The major clinical presentation in four patients was fever and diffuse superficial and intraabdominal adenopathy, with or without hepatosplenomegaly. Other sites were also affected: three patients had multiple osteoarticular lesions, occasionally with intense tissue destruction; two had cutaneous eruptions; two had pericardial effusions; and two had pulmonary involvement, once considered an organ spared in the young. We detected variable lymphocyte responses to mitogens and to Candida albicans antigen and non-responsiveness to Paracoccidioides brasiliensis cell wall antigen. High concentrations of serum immunoglobulins and anti-P. brasiliensis antibodies were present. These immune alterations tended to resolve with treatment, suggesting a reversible nature of the immune defect. We conclude that this mycosis has a high morbidity and mortality in children, which is probably related to an antigen-specific immunodeficiency. Further studies are needed to increase knowledge of this mycosis in children.

Placental involvement in paracoccidioidomycosis

A case of juvenile-type paracoccidioidomycosis in a pregnant woman is reported. The disease pre-dated pregnancy and antifungal treatment was being administered when she became pregnant. A premature male infant was delivered with no evidence of infection. Microscopic examination of the placenta showed numerous Paracoccidioides brasiliensis yeast forms in the intervillous space, enmeshed in a macrophagic-phagocytic reaction, with damage of the trophoblastic layer. Placental transfer of specific P. brasiliensis antibodies was demonstrated.

Sensitive immunoradiometric assay for the detection of Paracoccidioides brasiliensis antigens in human sera

In the present study we report the standardization of an immunoradiometric assay (IRMA) for detection of Paracoccidioides brasiliensis circulating antigens that could be useful in the diagnosis and prognosis of paracoccidioidomycosis. For this purpose we studied the reactivities of P. brasiliensis and other mycotic antigens with rabbit polyclonal anti-P. brasiliensis antibodies (immunoglobulin G) in order to evaluate the sensitivity and specificity of an IRMA for detecting P. brasiliensis antigens. The results were compared with those obtained by the double immunodiffusion test, the standard technique for the serodiagnosis of paracoccidioidomycosis. By using the immunoglobulin G fraction of rabbit antisera (900 ng per well), it was possible to detect up to 3.6 ng (0.12 micrograms/ml) of cellular antigen and 360 ng (12 micrograms/ml) of metabolic antigen in contrast to the double immunodiffusion test that could detect only 12 micrograms (1.2 mg/ml) of both antigens. IRMA was shown to be feasible and very sensitive and may therefore help, together with clinical data, in establishing early diagnosis and assessing disease activity. It could also allow the study of relationships between P. brasiliensis circulating antigens and host defense mechanisms during the disease.

Microimmunodiffusion test for the serodiagnosis of paracoccidioidomycosis

We used the micro- and macroimmunodiffusion test for the qualitative and quantitative measurement of anti - P. brasiliensis antibodies in serum of patients with paracoccidioidomycosis. All 103 paracoccidioidomycosis sera (100%) were positive in the micro test versus 87% positivity index in the macrotest. All 83 control sera from patients with other diseases were negative in both tests. Titers of the positive sera tended to be higher in the microtest, which revealed sharper and easier to read precipiting bands. Microimmunodiffusion is simple to be performed, requires a minimum amount of reagents and allows the simultaneous testing of 102 sera. It may replace the macrotest specially in laboratories dealing with great serologic routine.

In situlocalization of T lymphocyte subsets in human paracoccidioidomycosis

Immunohistochemical techniques using monoclonal antibodies to T lymphocyte subsets were used to characterize granulomas caused by Paracoccidioides brasiliensis. Punch biopsies of skin or mucosa from eight patients and of lymph nodes from two patients with disseminated paracoccidioidomycosis were studied. The T lymphocytes were distributed either in a localized pattern related to epithelioid granulomas or in a diffuse arrangement, predominantly around the vessels. In the granulomas, T cells formed a peripheral mantle surrounding central aggregates of macrophages. The majority of lymphocytes were T-helper cells with few suppressor cells. In contrast, patients presented with a decreased number of peripheral T-helper lymphocytes and a corresponding decrease in helper-suppressor cell ratios. There was no clear-cut relationship between tissue helper-suppressor cell ratios and the level of cellular immunodepression of the patients. The lowest P. brasiliensis antibody titers were detected in patients with the highest tissue helper-suppressor cell ratios. The distribution pattern of T lymphocytes in P. brasiliensis granulomas, with a predominance of helper phenotype, suggests that these cells are actively involved in the disease process.

Magnetic enzyme-linked immunosorbent assay (MELISA) for determination of specific IgG in paracoccidioidomycosis.

A magnetic solid phase enzyme-linked immunosorbent assay (MELISA) for quantification of IgG antibodies to somatic and metabolic antigens of Paracoccidioides brasiliensis was developed. Activation of magnetic polyacrylamide agarose beads with concanavalin A was superior to glutaraldehyde activation, and test sensitivity was higher for somatic than for metabolic antigens. Comparative MELISA, counterimmunoelectrophoresis and erythroimmunoassay tests with sera from 33 proven cases of paracoccidioidomycosis, 14 cases of histoplasmosis and 20 normal human sera showed the MELISA could distinguish antibody levels in paracoccidioidomycosis from those in normal sera; however two sera from histoplasmosis cases cross-reacted in the MELISA. MELISA is a rapid test (5-6 h) and the results suggest it has considerable potential value for assay of anti-P. brasiliensis antibodies.

Serology of paracoccidioidomycosis. II. Correlation between class-specific antibodies and clinical forms of the disease

Untreated and previously treated patients with paracoccidioidomycosis were studied for: (i) serum levels of total IgG, IgM and IgA immunoglobulins, by radial immunodiffusion and Paracoccidioides brasiliensis (Pb) antibodies, by indirect immunofluorescence; (ii) correlation between their levels with the clinical forms of the disease; (iii) correlation between the serum titres obtained by tube precipitin with those of anti- Pb IgG, IgM and IgA. In the untreated group, serum IgG levels were significantly increased in patients with the more systemic forms of the disease, especially the acute progressive form. Serum IgA levels were significantly increased in all patients with no statistical difference between clinical forms. Serum IgM levels were normal in all patients. Anti- Pb IgG, IgA and IgM were detected in 97·5%, 32·5% and 45·0% of all cases, respectively. There was a sharp tendency towards higher levels of anti- Pb IgG among those with the acute progressive form (83·4%) in relation to the chronic, more localized forms, mixed form (68·0%) and isolated organic form (55·5%). In the untreated and previously treated group sera, there was positive correlation between the level of anti- Pb IgG and positivity for the tube precipitin test, suggesting that the precipitin-type antibodies are of the IgG class. Broadly, the present data demonstrate a polyclonal activation of the humoral immune system in paracoccidioidomycosis, with a positive relationship between serological results and severity of the disease.

Indirect fluorescent test for detection of anti- Paracoccidioides brasiliensis antibodies using coated bentonite particles as antigen

An indirect fluorescent test was developed for detecting antibodies to Paracoccidioides brasiliensis using bentonite particles as antigen (Bent-IF). The bentonite particles were coated with P. brasiliensis polysaccharide antigen and tested with sera from paracoccidioidomycosis patients (36 sera), normal blood donors (32 sera) and patients with non-mycotic diseases (29 sera). The titres given by the positive sera were compared with those of complement fixation (CF), immunodiffusion (ID) and immunofluorescent test using yeast forms of the fungus as antigen (conventional-IF). All normal blood donors' sera gave a negative Bent-IF, conventional-IF, ID and CF tests. All paracoccidioidomycosis sera were reactive in conventional-IF and gave concordant results in Bent-IF. There was no correlation between CF and Bent-IF titres. 27·6% of sera from patients with non-mycotic diseases gave weak titres in both IF-tests. The present data indicate that the Bent-IF is a sensitive and simple serodiagnostic technique comparable with the conventional P. brasiliensis antibody test.