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Antigen-specific immunosuppression in paracoccidioidomycosis
G Benard1, M A Hong, G M Del Negro
1Immunogenetic and Experimental Transplantation Laboratory, Faculty of Medicine, University of Sao Paulo, Brazil.
The American Journal of Tropical Medicine and Hygiene
|January 1, 1996
Summary
Patients with paracoccidioidomycosis exhibit an antigen-specific immune defect, particularly to the P. brasiliensis antigen (PbAg). This hyporesponsiveness reverses with successful treatment, indicating a treatable cellular immunity dysfunction.
Area of Science:
- Immunology
- Infectious Diseases
- Mycology
Background:
- Paracoccidioidomycosis is a systemic fungal infection caused by Paracoccidioides brasiliensis.
- Immune dysfunction is a hallmark of paracoccidioidomycosis, but its specific characteristics remain incompletely understood.
Purpose of the Study:
- To characterize the immune dysfunction in patients with paracoccidioidomycosis.
- To assess lymphocyte reactivity to specific antigens and mitogens.
- To evaluate the reversibility of immune defects after treatment.
Main Methods:
- In vitro lymphocyte proliferation assays were performed using phytohemagglutinin (PHA), pokeweed mitogen (PWM), Candida albicans antigen (CMA), and Paracoccidioides brasiliensis antigen (PbAg).
- Studies included 32 patients with acute or chronic paracoccidioidomycosis before and after treatment, and 30 healthy controls.
- Additional immune parameters like skin tests, antibody levels, and lymphocyte subsets were analyzed.
Main Results:
- Patients showed significant hyporesponsiveness to PbAg, while responses to mitogens and CMA were comparable to controls.
- Acute paracoccidioidomycosis patients exhibited more pronounced PbAg hyporesponsiveness than chronic patients.
- Post-treatment, PbAg responses normalized, and correlations were found between PbAg response and eosinophil/antibody levels.
Conclusions:
- Paracoccidioidomycosis is characterized by an antigen-specific cellular immunity defect, particularly against PbAg.
- This immune defect is reversible with successful clinical treatment.
- The findings suggest a potential role for a T helper cell-2 immune response pattern in active disease.