Figure 1:

Myeloid-derived suppressor cells (MDSC) are enriched in peripheral blood mononuclear cells (PBMC) of participants with active TB disease compared to healthy controls, with the monocyte-like subset (M-MDSC) being the dominant subset compared to the granulocytic-type subset (PMN-MDSC). (a) The percentage of total PBMC for total MDSC, M-MDSC and PMN-MDSC subsets were compared in participants with active TB disease (n = 38) at the time of diagnosis and (b) in Healthy Controls (n = 10). (c) Total MDSC frequencies (p = 0.0161), (d) M-MDSC frequencies (p = 0.0496), and (e) PMN-MDSC frequencies (p = 0.0003) in PBMC were observed to be upregulated in participants with active TB disease (n = 38) at the time of diagnosis compared to frequencies observed in healthy control participants (n = 10). (f) Longitudinal M-MDSC frequencies in adult active TB disease cases. M-MDSC frequencies were investigated at the time of diagnosis/baseline (BL; n = 21), week two following treatment initiation (W2; n = 21), one month (M1; n = 24), two months (M2; n = 24), and six months (M6; n = 23) after treatment initiation and compared to healthy control participants (n= 16). Frequencies were determined using the FACS Canto II flow cytometer, and the third-party software FlowJo. D’Agostino & Pearson Omnibus test for normality was used to determine the distribution of the datasets: Kruskal-Wallis tests (a & b), Mann-Whitney tests (c-e), and a one-way ANOVA with Tukeys post-hoc test (f) were used where appropriate. Error bars represent the median and range. ***P < 0.001; **P < 0.01; *P < 0.05; ns: not significant.