Abstract:Objective To study the levels of toll-like receptor (TLR) 2 and TLR4 in peripheral blood mononuclear cells (PBMC) and their correlation with T follicular helper （Tfh） cell immune response in children with Henoch-Schonlein purpura (HSP). Methods Twenty-three children with primary HSP hospitalized Affiliated Hospital of Xuzhou Medical University from May to October in 2019 were selected as the study subjects (HSP group), and 15 children undergoing physical examination at the same time were served as control group. In two groups, the flow cytometry was used to detect the levels of TLR2, TLR4 and Tfh cells in PBMC, and ELISA was employed to determine the changes in interferon-γ(IFN-γ), interleukin(IL)-4, IL-6 and IL-21 levels in the plasma. Results Compared with those in control group, the expressions of TLR2 and TLR4, the proportion of peripheral Tfh cells and the plasma levels of IL-4, IL-6 and IL-21 in HSP group significantly increased,and IFN-γ level and IFN-γ/IL-4 significantly decreased in HSP group(P<0.01).In the children with acute HSP, the expressions of TLR2(r=0.538，r=0.800) and TLR4 (r=0.671，r=0.660)were respectively positively correlated with Tfh cells and IL-21 levels (P<0.01). Conclusion Activation of TLR2 and TLR4 may be involved in the occurrence and development of HSP and its immune-mediated pathogenesis by up-regulating the immune response of TFH cells.