IFN-<i>γ</i>-, IL-4-, IL-17-, PD-1-Expressing T Cells and B Cells in Peripheral Blood from Tuberculosis Patients

Abstract

Although the efficacy of tuberculosis (TB) vaccines is tightly linked to cell-mediated immunity, some functions of T and B cells in TB patients remain unclear. To address how Mycobacterium tuberculosis infection inhibits T effector responses, we assessed the proportions of T cell subsets and B cells in peripheral blood from pulmonary TB (PTB) patients, pleural TB (PLTB) patients, and healthy subjects (HS, who showed purified protein derivative (PPD)-positive reactions) with flow cytometry. Compared to HS, PTB and PLTB patients exhibited higher proportions of B cells and Th17 cells, and lower proportions of Th2 cells and ratios of Th1 to Th17 cells and of Th2 to Th17 cells. PTB patients had higher CD4 + T cells and PD-1 + CD4 + T cells than HS. Newly diagnosed PTB patients (nPTB) had higher proportions of B cells than HS; in contrast, PTB patients subjected to effective treatments (oPTB) and HS shared similar proportions of B cells. oPTB patients had higher proportions of CD4 + T cells, Th17 cells, and PD-1 + CD4 + T cells than HS, but this difference did not occur in nPTB patients. These findings suggest that shifting ratios of Th1 to Th17 cells may be beneficial for M. tuberculosis to amplify.

Cell Differentiation Degree as a Factor Determining the Role for Different T-Helper Populations in Tuberculosis Protection

“…Transcriptional and clinical analyses of healthy adolescents in South Africa revealed an association between inhibited Th17 responses and TB development (100). However, comparison of Th17/IL-17 levels in LTBI subjects and TB patients yielded inconsistent results: some studies reported heightened Th17/IL-17 levels in LTBI subjects (101–103), others demonstrated increased Th17/IL17 in TB patients (104–107), some did not reveal differences between LTBI and TB groups (108) or found extremely low frequencies of Mtb -specific Th17 in both groups (109, 110). In our study, Mtb -specific Th17 were rare in the blood, but readily identifiable in the lungs of TB patients (110).…”