Diminished circulating plasma and elevated lymph node culture supernatant levels of IL-10 family cytokines in tuberculous lymphadenitis

Abstract

BackgroundIL-10 family cytokines are associated with the host immune response to pulmonary tuberculosis (PTB), but their association with host response in tuberculous lymphadenitis (TBL) is not known. MethodsHence, we examined the circulating levels of the whole panel of IL-10 family cytokines in TBL (n = 44) and compared them to the levels in PTB (n = 44) and healthy control (HC, n = 44) individuals. We also assessed the pre and post-treatment cytokine levels in TBL individuals following the completion of anti-tuberculosis treatment (ATT). Next, we also compared the levels of IL-10 family cytokine in circulation versus lymph node (LN) culture supernatants in a subset of TBL individuals (n = 22). Finally, we also measured the levels of IL-10 family cytokines in tuberculosis antigen (purified protein derivative, PPD) stimulated and unstimulated LN culture supernatants. ResultsTBL individuals exhibit significantly decreased levels of IL-10, IL-19, IL-20, IL-24, IL-28B and IL-29 in the circulation when compared to PTB (except IL-10) and HC (except IL-20 and IL-28B) and significantly increased levels of IL-22 when compared to PTB individuals. Following ATT, TBL individuals exhibit significantly elevated levels of IL-10, IL-19, IL-20, IL-24, IL-28B and IL-29 and significantly diminished levels of IL-26. Similarly, TBL individuals also exhibited significantly increased levels of IL-10, IL-19, IL-20, IL-24, IL-28A and IL-29 in LN culture supernatants compared to plasma and significantly decreased levels of IL-22. This was associated with enhanced levels of IL-19, IL-20, IL-24, IL-28B and IL-29 upon PPD stimulation of LN cultures. ConclusionsTherefore, we demonstrate that TBL is associated with significantly diminished plasma and elevated LN culture supernatant levels of most of the IL-10 family cytokines. This to our knowledge is the first comprehensive examination of IL-10 family cytokines in TBL.