Elevated Serum Levels of CCL17 Correlate with Increased Peripheral Blood Platelet Count in Patients with Active Tuberculosis in China

Abstract

The serum levels of Th2 markers, including CCL17 (thymus and activation-regulated chemokine [TARC]), CCL22 (macrophage-derived chemokine [MDC]), and soluble CD30, were measured in 101 HIV-negative tuberculosis patients, 103 healthy community controls, and 18 tuberculosis patients in recovery. The levels of CCL17/TARC (249.8 ± 19.91 versus 143.9 ± 10.54, P < 0.0001) and sCD30 (7.78 ± 0.44 versus 4.93 ± 0.23, P < 0.0001) were significantly higher in patients with active tuberculosis than in controls; however, the CCL22/MDC serum level had no statistical difference between the groups (579.9 ± 16.42 versus 556.5 ± 15.29, P = 0.298). The counts of platelet and eosinophil in the peripheral blood of patients with active tuberculosis are significantly increased as well (289.4 ± 8.14 versus 248.3 ± 5.34 [P < 0.0001] and 165.1 ± 14.33 versus 102.5 ± 10.72 [P = 0.0005], respectively), and the platelet counts were positively correlated with serum TARC levels (Pearson r = 0.456, P < 0.0001), which indicates a new source of Th2 bias showing in active TB patients.