Cytokines in Different Forms of Pulmonary Tuberculosis

Abstract

The acquired T cell responses are critical for the host defense against Mycobacterium tuberculosis, yet their mechanisms of action remain unclear. Conflicting results have been demonstrated over the years, possibly due to the disregarded vitamin D levels, different forms of tuberculosis (TB), and methods used. The objective of the study was to investigate the production of 9 cytokines by the peripheral blood mononuclear cells, both PPD-stimulated and spontaneous, in patients with infiltrative (IT), fibrous cavernous tuberculosis (FCT), and in healthy donors. Blood samples were obtained in April-June in the Saint Petersburg region (59° north latitude). The level of 25 (OH) D was very low even in healthy adult donors - 19.3±1.4 ng/ml; however in all patients it was yet significantly lower. The induced production of IFN-γ, IL-2, IL-17, and IL-8 by the peripheral blood mononuclear cells was significantly increased in the patients of both tuberculosis groups, but the levels of TNF-α, IL-1β and IL-6 production, not stimulated by PPD, were lower in the tuberculosis patients than in healthy donors. We found a significant difference between the two groups of TB patients in the levels of the induced production of IFN-γ and IL-6, and the spontaneous production of TNF-α. The more severe course of TB and the lower vitamin D level in the FCT patients than in the IT patients was accompanied by higher levels of IFN-γ, TNF-α, IL-17, and IL-8 whose detrimental action was not restrained by IL-10 that failed to respond by the increase of its production.