IL-10 and Its Related Superfamily Members IL-19 and IL-24 Provide Parallel/Redundant Immune-Modulation in Loa loa Infection.

<bold>Background: </bold>Interleukin-10 (IL-10) has been implicated as the major cytokine responsible for the modulation of parasite-specific responses in filarial infections; however, the role of other IL-10 superfamily members in filarial infection is less well studied.<bold>Methods: </bold>Peripheral blood mononuclear cells from loiasis patients were stimulated with or without filarial antigen. Cytokine production was quantified using a Luminex platform and T-cell expression patterns were assessed by flow cytometry.<bold>Results: </bold>All patients produced significant levels of IL-10, IL-13, IL-5, IL-4, and IL-9 in response to filarial antigen, indicating a common infection-driven response. When comparing microfilaria (mf)-positive and mf-negative patients, there were no significant differences in spontaneous cytokine nor in parasite-driven IL-10, IL-22, or IL-28a production. In marked contrast, mf-positive individuals had significantly increased filarial antigen-driven IL-24 and IL-19 compared to mf-negative subjects. mf-positive patients also demonstrated significantly higher frequencies of T cells producing IL-19 in comparison to mf-negative patients. T-cell expression of IL-19 and IL-24 was positively regulated by IL-10 and IL-1β. IL-24 production was also regulated by IL-37.<bold>Conclusion: </bold>These data provide an important link between IL-10 and its related family members IL-19 and IL-24 in the modulation of the immune response in human filarial infections.<bold>Clinical Trials Registration: </bold>NCT00001230. [ABSTRACT FROM AUTHOR]