Disparity in circulating peripheral blood dendritic cell subsets and cytokine profile of pulmonary tuberculosis patients compared with healthy family contacts

Dendritic cell (DC) subsets, myeloid DCs (mDCs), and plasmacytoid DCs (pDCs) play a fundamental role in immune response to Mycobacterium tuberculosis (M. tuberculosis). Flow-cytometric estimation of DC subsets showed differences in the ratio of these subsets in untreated, smear-positive pulmonary tuberculosis patients compared with healthy family contacts (HFC, p < 0.05). The percentage of pDCs (0.14 ± 0.01) was higher than mDCs (0.12 ± 0.01) in patients, whereas in HFC, mDCs (0.15 ± 0.01) was higher than pDCs (0.1 ± 0.01). The percentage of mDCs (0.15 ± 0.01) and pDCs (0.11 ± 0.01) was restored in treated patients. Alteration in the DC subsets before and after chemotherapy was confirmed in the follow-up of acid-fast bacilli (AFB)–positive patients. This reversal in the percentage of mDC vs pDCs implicates the influence of active disease on circulating DC subsets. The cytokine bead array revealed an inverse relationship in the circulating levels of IL-12 and IFN-γ. High IL-12 (37.9 ± 15.2) and low IFN-γ (11.09 ± 3.6) was seen in HFCs derived serum samples compared with that of patients (p < 0.05). The higher percentage of mDCs and elevated IL-12 levels was found to be associated with high risk HFCs investigated. Furthermore CpG/LPS–stimulated whole-blood culture of untreated patients expressed high IFN-α in pDCs and less IL-12 in mDCs compared with those of treated patients.