Impact of tuberculosis treatment and antiretroviral therapy on serial RD-1-specific quantitative T-cell readouts (QuantiFERON-TB Gold In-Tube), and relationship to treatment-related outcomes and bacterial burden
International Journal of Infectious Diseases
South African Medical Research Council, Parow Valley, Cape Town, South Africa; KwaZulu-Natal Research Institute for Tuberculosis and HIV (K-RITH), Nelson Mandela School of Medicine, Durban, South Africa; South African Medical Research Council, Biostatistics Department, Durban, South Africa; World Health Organization, Special Programme for Research and Training in Tropical diseases (TDR), Geneva, Switzerland; Lung Infection and Immunity Unit, Division of Pulmonology, Department of Medicine, Groote Schuur Hospital, Observatory, University of Cape Town, J flr, Old Main Bldg, Cape Town, South Africa
Background: The impact of anti-tuberculosis treatment with and without antiretroviral therapy (ART) on standardized interferon gamma release assay (IGRA) readouts has been studied inadequately in high-burden countries. Methods: The QuantiFERON-TB Gold In-Tube (QFT-GIT) test was used to evaluate interferon gamma (IFN-γ) responses longitudinally (0, 3, 6, and 12 months post initiation of tuberculosis (TB)-HIV co-treatment or ART alone) in 82 HIV-infected patients. Results: Of the 65 evaluable participants, 30 were co-infected on ART, 17 were co-infected but not on ART, and 18 were HIV-infected alone and on ART. In HIV-infected and HIV-TB-infected patients on ART, IFN-γ responses increased, whilst they decreased in those not on ART. However, baseline, month 3, and month 6 IFN-γ responses, irrespective of ART, did not differ in TB-HIV co-infected patients who culture-converted compared to those who did not (1.25 vs. 1.05, p = 0.5 at baseline; 3.76 vs. 1.15, p = 0.2 for month 3; 0.06 vs. 0.7, p = 0.3 for month 6). IFN-γ levels did not correlate with the magnitude of sputum bacillary load, smear status, or liquid culture time-to-positivity. Conclusion: As IGRAs do not correlate with 2- or 6-month culture conversion or with markers of bacillary burden, they are unlikely to be useful for the prognostication of treatment outcome in co-infected patients. © 2015 The Authors.
antiretrovirus agent; adult; aged; antiviral therapy; Article; bacterial load; controlled study; female; human; Human immunodeficiency virus infection; interferon gamma release assay; liquid culture; major clinical study; male; mixed infection; Mycobacterium tuberculosis test kit; sputum culture; T lymphocyte; treatment outcome; treatment response; tuberculosis