Plasmalyte as a cause of false-positive results for Aspergillus galactomannan in bronchoalveolar lavage fluid.
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Antigens, Fungal↗
Biomedical subjects
Chadi A Hage
Publications and source records attributed to Chadi A Hage.
Functional impairment of CD4 T cells despite normalization of T cell number in HIV.
Using an in vitro model, we demonstrate that when CD4 T cells from HIV infected subjects are enriched from total blood lymphocytes the immune response to antigen is augmented. However, augmentation of this response is confined to HIV infected subjects with relatively preserved CD4 T cell counts. Enriching for CD4 T cells had no effect on antigen responses in patients with low CD4 lymphocyte counts. These findings support the concept that CD4 T cells in late stage HIV have inherent qualitative defects.
Adult↗
Diagnosis of pulmonary histoplasmosis and blastomycosis by detection of antigen in bronchoalveolar lavage fluid using an improved second-generation enzyme-linked immunoassay.
Antigen detection is a useful adjunct for the diagnosis of histoplasmosis. The purpose of this study was to evaluate antigen detection in bronchoalveolar lavage (BAL) fluid using an improved second-generation Histoplasma antigen assay. Antigen was detected in 16 of 19 (84%) cases of histoplasmosis and 5 of 6 (83.3%) blastomycosis cases using the second-generation assay vs. 13 of 19 (68%) and 4 of 6 (66.7%), respectively, in the original assay. Ten-fold concentration permitted detection of antigen in an additional case of histoplasmosis and another with blastomycosis, for an overall sensitivity of 23 of 25 (92.0%). Specificity was 98.2% in both assays in controls with other pulmonary infections. These findings support the diagnostic utility of the second-generation assay in patients with pulmonary histoplasmosis and blastomycosis.
Antigens, Fungal↗
Cytometric analysis of BAL T cells labeled with a standardized antibody cocktail correlates with immunohistochemical staining.
BACKGROUND: Determining T-cell phenotypes of lung cells obtained by bronchoalveolar lavage (BAL) is frequently clinically useful, particularly for evaluating causes of interstitial lung disease. The current standard of determining CD4/CD8 T-cell subsets by immunohistochemical (IHC) staining of cytocentrifuge slides is labor-intensive and subject to interpreter variation. Flow cytometry (FCM) is a precise and rapid method commonly used in research to characterize cells in the lung. However, few studies address the methodology of analysis of BAL lymphocytes by FCM. METHODS: Patients underwent bronchoscopy for clinical purposes. A BAL cell differential and T-cell subtype was requested by the treating physician to supplement the evaluation of patients with suspected interstitial lung disease. We used a commercially available T-cell antibody reagent, approved for analysis of blood via FCM, for T-cell subtyping of clinical BAL specimens. RESULTS: The percentages of CD4 and CD8 T-cell populations, as well as the CD4/CD8 ratios showed excellent correlation with IHC staining of cytocentrifuge slides regardless of the acquisition program used, as long as the gating strategy remained consistent (r > or = 0.9693 for CD4, r > or = 0.9589 for CD8, and r > or = 0.9485 for the CD4/CD8 ratio). CONCLUSION: These findings validate the use of standardized, commercially available antibody cocktails for BAL lymphocyte subtyping, making this technique available to clinicians and researchers with access to a three-color or four-color flow cytometer.
Antibodies↗
Infliximab does not affect dendritic cells' mediated lymphoproliferative response to Histoplasma capsulatum.
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Antibodies, Monoclonal↗
Human immunodeficiency virus gp120 downregulates CD1d cell surface expression.
CD1d is an MHC class I-like surface molecule that presents endogenous glycoplipid antigens. The effect of HIV infection on CD1d surface expression has not yet been reported. FACS analysis revealed significantly lower levels of CD1d on CD14(+) monocytes from HIV-infected subjects compared to HIV-infected subjects on HAART and healthy controls. CD1d expression correlated inversely with viral load in infected individuals. CD1d surface expression on human cell lines was downregulated after infection with M-tropic HIV, T-tropic HIV, or after exposure to HIV gp120 in vitro. These data suggest that CD1d-mediated responses are altered during HIV infection and may thus contribute to the global immunodeficiency seen in these patients.
Antigens, CD1↗
Macrophages exposed to lymphotropic and monocytotropic HIV induce similar CTL responses despite differences in productive infection.
Macrophages are accessory cells that are vulnerable to infection by HIV-1. HTLV-IIIB, a lymphotropic strain of HIV, infects macrophages poorly resulting in either no or low levels of virus expression compared to high levels of productive infection after exposure of macrophages to the monocytotropic HIV strain Ada-M. Whether this results in an impaired ability of HTLV-IIIB-exposed macrophages to initiate protective cytotoxic T lymphocyte (CTL) immune responses against these strains is not well defined. We investigated the ability of monocyte-derived macrophages (MDM) exposed to lymphotropic and monocytotropic HIV strains to initiate primary CTL responses in vitro. MDM exposed to HTLV-IIIB induced a specific primary CTL response that was comparable to MDM exposed to the monocytotropic strain Ada-M despite marked differences in productive HIV infection in MDM between the two strains. CTL generated in this model were MHC-restricted, strain-specific, and CD8+. These data demonstrate that high levels of productive HIV infection in accessory cells are not a prerequisite for the generation of a primary CTL response, suggesting a novel immunologic interaction between MDM and lymphotropic HIV strains.
CD4-Positive T-Lymphocytes↗
Pathogenesis of pleural infection.
The pleura responds to the presence of infecting organisms with a vigorous inflammatory response associated with an exudation of white blood cells and proteins. The development and outcome of pleural infections is a function of a balance between the virulence of the invading microorganism and the immune reaction involving professional immune cells as well as the pleural mesothelial cells. Most commonly, pleural infection occurs after invasion through the lung parenchyma and a breach in the viscera pleura resulting in the formation of a parapneumonic process. Upon infection, the microorganisms are recognized by the pleural mesothelial cell, which remains the first line of defence. Pleural responses to infection include those of innate immunity as well as adaptive or acquired immunity. Innate and acquired immune responses are closely linked. In this review, we discuss the different virulence factors that allow microorganisms to infect the pleura and the role of the pleural mesothelial cells in bridging the innate and acquired immune responses.
Animals↗
Histoplasmosis after treatment with anti-tumor necrosis factor-alpha therapy.
Anti-tumor necrosis factor-alpha (TNF-alpha) antibodies are frequently used to treat inflammatory diseases. However, these drugs also have immunosuppressive effects. We report on three patients who developed disseminated histoplasmosis on therapy with TNF-alpha inhibitors. In vitro assays were used to characterize the role of these agents in host defense against Histoplasma capsulatum. Intracellular proliferation of H. capsulatum was measured in alveolar macrophages and peripheral monocytes of normal volunteers in the presence and absence of the TNF-alpha antibody, infliximab. Both infliximab and control antibody enhanced fungal growth in monocytes and alveolar macrophages, suggesting this was a nonspecific antibody response. Despite similar intracellular fungal loads in the presence of both antibodies, lymphocyte proliferation in response to blood monocytes and alveolar macrophages infected with H. capsulatum was inhibited by the addition of physiologic doses of infliximab, whereas control antibody had no effect. The production of H. capsulatum-induced interferon-gamma and TNF-alpha was assessed in 5-day cultures containing lymphocytes and alveolar macrophages or monocytes. Interferon-gamma secretion was significantly reduced in the presence of infliximab. In summary, patients receiving anti-TNF-alpha therapy are at risk for developing disseminated histoplasmosis. This may be due to a defect in the TH1 arm of cellular immunity.
Adolescent↗
Pulmonary cryptococcosis after initiation of anti-tumor necrosis factor-alpha therapy.
Many patients with rheumatoid arthritis are being treated with immunosuppressive regimens that include an agent directed at blocking tumor necrosis factor (TNF)-alpha. Although reportedly safe, tuberculous and fungal infections have emerged as significant complications of therapy. We report a case of pulmonary cryptococcosis soon after the initiation of therapy with the anti-TNF-alpha antibody, infliximab. A diagnosis was made early in the disease course, and the patient responded quickly to antifungal therapy. This case should alert clinicians to the increased incidence of pulmonary mycoses in patients receiving anti-TNF-alpha therapy.
Antibodies, Monoclonal↗