02144nas a2200169   4500000000100000008004100001653001800042653001900060653001900079653001200098100001600110700001400126700001200140245017400152856005600326520159200382       2023                            d10aInterleukin 910ainterleukin 1710alepra reaction10aleprosy1 aChoudhary R1 aChhabra N1 aPatel S00aComparison of serum levels of interleukin 17 and interleukin 9 in leprosy patients with and without lepra reaction: A cross-sectional analytical study from Central India  uhttps://www.e-ijd.org/preprintarticle.asp?id=3868623 a<p>New pathways of host defence have emerged in leprosy, such as T helper (Th) -17, Th-9, T regulatory cells, and other factors like transforming growth factor-beta, etc. Interleukin (IL) 17 produced by Th17 cells has been found to be elevated in lepra reaction, especially type 2 lepra reaction (T2R). Role of IL-9 has not been studied widely in leprosy reactions so far. The study aimed to compare serum levels of IL-17 and IL-9 in leprosy patients with and without lepra reaction. This was a cross-sectional analytical study including untreated adult leprosy patients with and without lepra reaction. A total of 65 patients were included in the study with 30 leprosy patients without reaction and 35 with lepra reaction. Serum levels of IL-17 and IL-9 were measured in these patients using direct enzyme-linked immunosorbent assay and were compared. Borderline tuberculoid (BT) leprosy with type 1 and Lepromatous (LL) leprosy with T2R patients showed significantly higher levels of IL-17 than BT and LL leprosy patients without lepra reaction, respectively. LL patients with T2R showed significantly lower levels of IL-9 than lepromatous cases without reaction. IL-9 levels were higher in BT patients with T1R as compared to BT patients without reaction but the difference was not significant. We found evidence in support of role of IL-17 in the pathogenesis of T2R, which might serve as useful serum markers for the same. IL-17 might have a role in BT leprosy with T1R. IL-9 seems to have a protective role in T2R as opposed to IL-17, working in synergism with Th1 cytokines.</p>