FcγRIIIa expression on monocytes in rheumatoid arthritis: role in immune-complex stimulated TNF production and non-response to methotrexate therapy.
<h4>Objective</h4>The expression of FcγRIIIa/CD16 may render monocytes targets for activation by IgG-containing immune complexes (IC). We investigated whether FcγRIIIa/CD16 was upregulated in rheumatoid arthritis (RA), associated with TNF production in response to IC-stimulation, and if...
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Autores principales: | , , , , , , , , , |
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Formato: | article |
Lenguaje: | EN |
Publicado: |
Public Library of Science (PLoS)
2012
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Materias: | |
Acceso en línea: | https://doaj.org/article/7dfe4c7e8db24f158c23d451fe0c074d |
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Sumario: | <h4>Objective</h4>The expression of FcγRIIIa/CD16 may render monocytes targets for activation by IgG-containing immune complexes (IC). We investigated whether FcγRIIIa/CD16 was upregulated in rheumatoid arthritis (RA), associated with TNF production in response to IC-stimulation, and if this predicted response to methotrexate therapy.<h4>Methods</h4>FcγRIIIa/CD16 expression on CD14(low) and CD14++ monocytes was measured by flow cytometry in healthy controls and RA patients (early and long-standing disease). Intracellular TNF-staining was carried out after in vitro LPS or heat-aggregated immunoglobulin (HAG) activation. FcγRIIIa/CD16 expression pre- and post-steroid/methotrexate treatment was examined.<h4>Results</h4>Increased FcγRIIIa/CD16 expression on CD14++ monocytes in long-standing RA patients compared to controls was demonstrated (p = 0.002) with intermediate levels in early-RA patients. HAG-induced TNF-production in RA patients was correlated with the percentage of CD14++ monocytes expressing FcγRIIIa/CD16 (p<0.001). The percentage of CD14++ monocytes expressing FcγRIIIa/CD16 at baseline in early DMARD-naïve RA patients was negatively correlated with DAS28-ESR improvement 14-weeks post-methotrexate therapy (p = 0.003) and was significantly increased in EULAR non-responders compared to moderate (p = 0.01) or good responders (p = 0.003). FcγRIIIa/CD16 expression was not correlated with age, presence of systemic inflammation or autoantibody titers.<h4>Conclusion</h4>Increased FcγRIIIa/CD16 expression on CD14++ monocytes in RA may result in a cell that has increased responsiveness to IC-stimulation. This monocyte subset may contribute to non-response to methotrexate therapy. |
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