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

Molly A Vickers,Fatoumatta Darboe,Caleb N Muefong,Hazel M Dockrell,Awa Gindeh,Jayne S Sutherland,Shamanthi Jayasooriya,Salome Charalambous,Sainabou Njie,Abi-Janet Riley,Binta Sarr,Basil Sambou,Georgetta Mbayo,Olumuyiwa Owolabi,Andrea Rachow,Amadou Barry

doi:10.3389/fimmu.2020.572620

Abstract

BackgroundBlood-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.MethodsWhole blood immune responses to Mycobacterium tuberculosis 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.ResultsThere was a significant increase in the proportion of CD4+CD27+ cells expressing CD38 and HLA-DR following EC stimulation at 2 months compared to baseline (p = 0.0328 and p = 0.0400, respectively). Following PPD stimulation, slow treatment responders had a significantly higher proportion of CD8+CD27–IFN-γ+ (p = 0.0105) and CD4+CD27+HLA-DR+CD38+ (p = 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, p = 0.0156 and 0.84, p = 0.0102).ConclusionOur 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.

Highlights

The World Health Organization’s (WHO) 2018 Global Tuberculosis (TB) report estimated that 10 million people developed active TB (ATB) disease in 2018 resulting in 1.6 million deaths [1]
The aim of this study was to determine the potential use of activation markers expressed on both CD4+ and CD8+ T-cells for monitoring ATB treatment response in a longitudinal cohort of ATB adults from West Africa
There was no significant difference in age between the fast and slow responders, with a median[interquartile range (IQR)] of 25 [22–31] and 32 [28–35] years, respectively (Table 1). 80% were male in both groups and all were HIV negative

Summary

Introduction

The World Health Organization’s (WHO) 2018 Global Tuberculosis (TB) report estimated that 10 million people developed active TB (ATB) disease in 2018 resulting in 1.6 million deaths [1]. Sputum smear and microscopy lacks sensitivity [2,3,4] and the time-lag in receiving Mtb sputum culture results limits their clinical application in identifying those that are not responding to treatment. All of these techniques require sputum samples, which are often difficult to obtain from individuals after 2 months of treatment [5, 6] at a time when there is the potential for modifying treatment regimens. 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

Objectives

Methods

Results

Conclusion