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Monocyte dysfunction in patients with acquired immunodeficiency syndrome (AIDS) versus Cryptococcus neoformans
C Monari1, F Baldelli, D Pietrella
1Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Italy.
The Journal of Infection
|February 12, 1998
Summary
Monocytes from AIDS patients show impaired antifungal activity against Cryptococcus neoformans, struggling with fungal uptake and T-lymphocyte response, contributing to cryptococcosis progression.
Area of Science:
- Immunology
- Infectious Diseases
- Cell Biology
Background:
- AIDS patients with low CD4 counts are susceptible to opportunistic infections like cryptococcosis.
- Monocytes play a crucial role in the immune response against fungal pathogens.
Purpose of the Study:
- To investigate the functional response of monocytes from AIDS patients against Cryptococcus neoformans.
- To identify specific defects in monocyte function that may contribute to cryptococcosis.
Main Methods:
- Comparison of monocyte responses (phagocytosis, superoxide production, TNF-alpha release) from AIDS patients and healthy donors.
- Assessment of Cryptococcus neoformans internalization by monocytes.
- Evaluation of T-lymphocyte activation by cryptococcus-laden monocytes.
Main Results:
- Monocytes from AIDS patients exhibited impaired fungicidal activity against C. neoformans.
- Reduced phagocytosis of C. neoformans by AIDS patient monocytes, linked to complement receptor type 3 dysfunction.
- Significantly decreased superoxide anion production and a weak T-lymphocyte response induced by cryptococcus-laden monocytes.
Conclusions:
- Monocyte dysfunction, including impaired phagocytosis and reduced microbicidal activity, contributes to cryptococcosis susceptibility in AIDS patients.
- Defective complement receptor type 3 function is implicated in the phagocytic defect.
- These monocyte defects may play a role in the progression of cryptococcosis in individuals with advanced HIV infection.