Impact of age and sex on mycobacterial immunity in an area of high tuberculosis incidence

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dc.contributor.authorGallant, C. J.
dc.contributor.authorCobat, A.
dc.contributor.authorSimkin, L.
dc.contributor.authorBlack, G. F.
dc.contributor.authorStanley, K.
dc.contributor.authorHughes, J.
dc.contributor.authorDoherty, T. M.
dc.contributor.authorHanekom, W. A.
dc.contributor.authorEley, B.
dc.contributor.authorBeyers, Nuldaen_ZA
dc.contributor.authorJais, J-P.
dc.contributor.authorVan Helden, Paul D.en_ZA
dc.contributor.authorAbel, L.
dc.contributor.authorAlcais, A.
dc.contributor.authorHoal, E. G.
dc.contributor.authorSchurr, E.
dc.date.accessioned2011-05-15T15:53:45Z
dc.date.available2011-05-15T15:53:45Z
dc.date.issued2010
dc.description.abstractSETTING: The extent of immune reactivity measured by the tuberculin skin test (TST) and interferon-gamma (IFN-γ) T-cell assays is usually not analysed. OBJECTIVE: To determine the impact of age and sex on assay positivity and on the extent of reactivity of both TST and T-cell assays in young persons in an area of South Africa with high TB transmission. RESULTS: Age had a strong impact on assay positivity for all seven immune phenotypes tested (P < 0.0007). Among positive responders, the extent of purified protein derivative (PPD) triggered IFN-γ release (P < 0.003) was sensitive to age. ESAT-6 triggered IFN-γ release (day 7, P = 0.03) and the frequency of PPD-specific IFN-γ+CD4+ (P = 0.03) and IFN-γ+CD8+ cells (P = 0.04) were weakly dependent on age. By contrast, the extent of TST induration was insensitive to age (P > 0.05), and sex had no significant impact on any phenotype measured (P > 0.05). The high proportion of positive responders in the 1-10 year age-group observed with long-term whole blood assays, but not with 3-day assays and TST, suggests that long-term whole blood assays may be confounded by bacille Calmette-Guérin vaccination in this age group. CONCLUSION: There is a significant impact of age, but not sex, on different assays of immune reactivity in this high TB transmission setting. © 2010 The Union.
dc.description.versionArticle
dc.identifier.citationInternational Journal of Tuberculosis and Lung Disease
dc.identifier.citation14
dc.identifier.citation8
dc.identifier.issn10273719
dc.identifier.urihttp://hdl.handle.net/10019.1/8793
dc.titleImpact of age and sex on mycobacterial immunity in an area of high tuberculosis incidence
dc.typeArticle
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