Monitoring Anti-tuberculosis Treatment Response Using Analysis of Whole Blood Mycobacterium tuberculosis Specific T Cell Activation and Functional Markers

Vickers, Molly A; Darboe, Fatoumatta; Muefong, Caleb N; Mbayo, Georgetta; Barry, Amadou; Gindeh, Awa; Njie, Sainabou; Riley, Abi-Janet; Sarr, Binta; Sambou, Basil; +6 more... Dockrell, Hazel M; Charalambous, Salome; Rachow, Andrea; Owolabi, Olumuyiwa; Jayasooriya, Shamanthi; Sutherland, Jayne S; (2020) Monitoring Anti-tuberculosis Treatment Response Using Analysis of Whole Blood Mycobacterium tuberculosis Specific T Cell Activation and Functional Markers. FRONTIERS IN IMMUNOLOGY, 11. ISSN 1664-3224 DOI: https://doi.org/10.3389/fimmu.2020.572620

Abstract

<jats:sec><jats:title>Background</jats:title><jats:p>Blood-based biomarkers have been proposed as an alternative to current sputum-based treatment monitoring methods in active tuberculosis (ATB). The aim of this study was to validate previously described phenotypic, activation, and cytokine markers of treatment response in a West African cohort.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Whole blood immune responses to <jats:italic>Mycobacterium tuberculosis</jats:italic> ESAT-6/CFP-10 (EC) and purified protein derivative (PPD) were measured in twenty adults at baseline and after 2 months of standard TB treatment. Patients were classified as fast or slow responders based on a negative or positive sputum culture result at 2 months, respectively. Cellular expression of activation markers (CD38, HLA-DR), memory markers (CD27), and functional intracellular cytokine and proliferation (IFN-γ, Ki-67, TNF-α) markers were measured using multi-color flow cytometry.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>There was a significant increase in the proportion of CD4<jats:sup>+</jats:sup>CD27<jats:sup>+</jats:sup> cells expressing CD38 and HLA-DR following EC stimulation at 2 months compared to baseline (<jats:italic>p</jats:italic> = 0.0328 and <jats:italic>p</jats:italic> = 0.0400, respectively). Following PPD stimulation, slow treatment responders had a significantly higher proportion of CD8<jats:sup>+</jats:sup>CD27<jats:sup>–</jats:sup>IFN-γ<jats:sup>+</jats:sup> (<jats:italic>p</jats:italic> = 0.0105) and CD4<jats:sup>+</jats:sup>CD27<jats:sup>+</jats:sup>HLA-DR<jats:sup>+</jats:sup>CD38<jats:sup>+</jats:sup> (<jats:italic>p</jats:italic> = 0.0077) T cells than fast responders at baseline. Receiver operating curve analysis of these subsets resulted in 80% sensitivity and 70 and 100% specificity, respectively (AUC of 0.82, <jats:italic>p</jats:italic> = 0.0156 and 0.84, <jats:italic>p</jats:italic> = 0.0102).</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Our pilot data show reductions in expression of T cell activation markers were seen with treatment, but this was not associated with fast or slow sputum conversion at 2 months. However, baseline proportions of activated T cell subsets are potentially predictive of the subsequent speed of response to treatment.</jats:p></jats:sec>