Augmented chemokine levels and chemokine receptor expression on immune cells during pulmonary tuberculosis

The systemic changes in immune mediators such as cytokine and chemokines, and their synchronized interaction that regulates the cell trafficking during Mycobacterium tuberculosis (M. tuberculosis) infection, were studied. Cytokines and chemokines were evaluated by cytometric bead array (CBA) and enzyme-linked immunosorbent assay (ELISA) in 34 pulmonary tuberculosis (PTB) patients and 30 healthy subjects. The expression of chemokine receptors was assessed by flow cytometry. A significant increase in IP-10, MIG, interleukin-8, RANTES, and interleukin-6 levels was found, whereas a decrease in interferon-gamma, tumor necrosis factor-alpha, and transforming growth factor-beta was observed during PTB. Significant correlation within chemokines and between cytokines was observed in PTB. All immune cells except monocytes and B cells expressed significantly higher levels of CCR1, CCR2, and CXCR2 whereas CCR7 expression was upregulated only on monocytes and neutrophils in PTB. Both T and B cells expressed significantly high levels of CXCR3 which also correlated well with the chemokine levels in PTB. Thus, it was found that chemokines function coordinately and consistently during PTB. This balanced chemokine and cytokine relationship at the periphery may aid in amplified effector immune cell trafficking and retarded monocyte migration through differential chemokine receptor expression.