In vitro levels of cytokines in response to purified protein derivative (PPD) antigen in a population with high prevalence of pulmonary tuberculosis.

The control of mycobacterial infection by the host depends on cell-mediated immunity (CMI), involving activated macrophages, T cells, and type 1 cytokines (Th1). Here we evaluated the capacity of antigen-induced proliferation by peripheral blood mononuclear cells (PBMCs) and the production of proinflammatory tumor necrosis factor-alpha (TNF-α) and interleukin 12 (IL-12p40). The Th1 cytokine interferon-gamma (IFN-γ) and Th2 cytokines interleukin 4 (IL-4) and interleukin 5 (IL-5) in 62 pulmonary tuberculosis (TB) patients (40 Warao indigenous patients [WP] and 22 Creole non-indigenous patients [CP]) and 24 healthy controls (12 Warao indigenous controls [WC] and 12 Creole non-indigenous controls [CC]) at 24 and 48 hours in response to purified protein derivative (PPD) from Mycobacterium tuberculosis. The overall results revealed that testing of CP and CC' PBMCs for TNF-α, IFN-γ, and IL-12p40 production was higher compared with WP and WC' PBMCs after stimulating for 24 and 48 hours (p < 0.0001), within the WP group, the lower productions of IL-12p40 and IFN-γ significantly correlated (r(2) = 0.91, p < 0.01). Although in general there was interindividual variability in the observed responses of Th2 cytokines, especially with IL-4, there was a trend to produce higher PPD-induced IL-5 by WP' PBMCs compared with WC' PBMCs and CP' PBMCs at 24 and 48 hours, respectively. High IL-5 production correlated inversely with low IFN-γ production (r(2) = -0.97, p < 0.002). In conclusion, our results suggest that PPD-induced responses observed in patients from both populations can be divided into two groups: one group that activates Creole' PBMCs to preferentially secrete TNF-α, IL-12p40 and IFN-γ and another group that activates preferential secretion of IL-5 in Warao' PBMCs.