Objective:To investigate the value of T helper 17 cells（Th17）/regulatory T cells（Treg）imbalance in the evaluation of intravenous immunoglobulin（IVIG）resistance in children with Kawasaki disease and Kobayashi score≤4.Methods:A total of 78 children with Kawasaki disease and Kobayashi score ≤ 4 admitted to Hunan Children's Hospital from January 2020 to December 2023 were prospectively selected as the study subjects，all of whom received IVIG treatment.In the acute phase，the proportion of Th17 cells and Treg cells was detected.Children were divided into IVIG sensitive group and IVIG resistance group based on their responsiveness to IVIG treatment.Baseline data of children with different IVIG treatment responsiveness，acute Th17 cell inflammatory factors [interleukin（IL）-17，IL-21，tumor necrosis factor-α（TNF-α）]，Treg cell inflammatory factors [IL-10，IL-35，transforming growth factor-β（TGF-β）] levels，and Th17/Treg values were compared.The correlation between Th17/Treg values and IVIG resistance in children with Kawasaki disease was analyzed using a restricted cubic spline model（RCS）.According to the threshold of correlation between Th17/Treg values obtained from RCS analysis and drug resistance in children，Th17/Treg was grouped，with a focus on analyzing the predictive value and clinical benefits of Th17/Treg values for IVIG resistance in children with Kawasaki disease.Results:Among the 78 children with Kawasaki disease，16 were resistant to IVIG treatment，accounting for 20.51%.The levels of C-reactive protein（CRP）,IL-17,and Th17/Treg in the acute phase of children in the IVIG resistance group were higher than those in the IVIG sensitive group，while the levels of IL-10 were lower than those in the IVIG sensitive group（ P<0.05）.RCS analysis showed that there was a non-linear dose-response relationship between IVIG resistance and acute Th17/Treg values in children with Kawasaki disease（ P<0.05）.When the acute Th17/Treg value was greater than 1.05，the risk of IVIG resistance in children with Kawasaki disease increased with the increase in indicator levels.The levels of CRP and IL-17 in the acute phase of children with Th17/Treg>1.05 were higher than those in the Th17/Treg < 1.05 group，while IL-10 levels were lower than those in the Th17/Treg<1.05 group.The proportion of children resistant to IVIG treatment was higher than that in the Th17/Treg<1.05 group（ P<0.05）.Multivariate Logistic regression analysis showed that CRP，IL-17，IL-10，and Th17/Treg were the influencing factors of IVIG resistance in children with Kawasaki disease（ P<0.05）.It was found through a nomogram that the C-index of the acute phase Th17/Treg values and their secretion of inflammatory factors in children with Kawasaki disease and Kobayashi score ≤ 4，as well as other major indicators，predicted the risk of IVIG resistance.The C-index was 0.975（95% CI 0.944-1.000），indicating good discrimination.When drawing the decision curve，it was found that compared to using each indicator separately，the Th17/Treg value and its secreted inflammatory factors in the acute phase assisted other major indicators in drawing the decision curve with a higher net benefit rate，with a maximum net benefit rate of 0.205. Conclusion:IVIG resistance in children with Kawasaki disease and Kobayashi score≤4 is related to Th17/Treg imbalance.When the Th17/Treg value in the acute phase of the disease is greater than 1.05，the risk of IVIG resistance is higher.The inflammatory factors IL-17 and IL-10 secreted by the two can assist other known indicators related to IVIG resistance in Kawasaki disease patients，improving the accuracy of predicting resistance risk.

Objective:To investigate the value of T helper 17 cells（Th17）/regulatory T cells（Treg）imbalance in the evaluation of intravenous immunoglobulin（IVIG）resistance in children with Kawasaki disease and Kobayashi score≤4.Methods:A total of 78 children with Kawasaki disease and Kobayashi score ≤ 4 admitted to Hunan Children's Hospital from January 2020 to December 2023 were prospectively selected as the study subjects，all of whom received IVIG treatment.In the acute phase，the proportion of Th17 cells and Treg cells was detected.Children were divided into IVIG sensitive group and IVIG resistance group based on their responsiveness to IVIG treatment.Baseline data of children with different IVIG treatment responsiveness，acute Th17 cell inflammatory factors [interleukin（IL）-17，IL-21，tumor necrosis factor-α（TNF-α）]，Treg cell inflammatory factors [IL-10，IL-35，transforming growth factor-β（TGF-β）] levels，and Th17/Treg values were compared.The correlation between Th17/Treg values and IVIG resistance in children with Kawasaki disease was analyzed using a restricted cubic spline model（RCS）.According to the threshold of correlation between Th17/Treg values obtained from RCS analysis and drug resistance in children，Th17/Treg was grouped，with a focus on analyzing the predictive value and clinical benefits of Th17/Treg values for IVIG resistance in children with Kawasaki disease.Results:Among the 78 children with Kawasaki disease，16 were resistant to IVIG treatment，accounting for 20.51%.The levels of C-reactive protein（CRP）,IL-17,and Th17/Treg in the acute phase of children in the IVIG resistance group were higher than those in the IVIG sensitive group，while the levels of IL-10 were lower than those in the IVIG sensitive group（ P<0.05）.RCS analysis showed that there was a non-linear dose-response relationship between IVIG resistance and acute Th17/Treg values in children with Kawasaki disease（ P<0.05）.When the acute Th17/Treg value was greater than 1.05，the risk of IVIG resistance in children with Kawasaki disease increased with the increase in indicator levels.The levels of CRP and IL-17 in the acute phase of children with Th17/Treg>1.05 were higher than those in the Th17/Treg < 1.05 group，while IL-10 levels were lower than those in the Th17/Treg<1.05 group.The proportion of children resistant to IVIG treatment was higher than that in the Th17/Treg<1.05 group（ P<0.05）.Multivariate Logistic regression analysis showed that CRP，IL-17，IL-10，and Th17/Treg were the influencing factors of IVIG resistance in children with Kawasaki disease（ P<0.05）.It was found through a nomogram that the C-index of the acute phase Th17/Treg values and their secretion of inflammatory factors in children with Kawasaki disease and Kobayashi score ≤ 4，as well as other major indicators，predicted the risk of IVIG resistance.The C-index was 0.975（95% CI 0.944-1.000），indicating good discrimination.When drawing the decision curve，it was found that compared to using each indicator separately，the Th17/Treg value and its secreted inflammatory factors in the acute phase assisted other major indicators in drawing the decision curve with a higher net benefit rate，with a maximum net benefit rate of 0.205. Conclusion:IVIG resistance in children with Kawasaki disease and Kobayashi score≤4 is related to Th17/Treg imbalance.When the Th17/Treg value in the acute phase of the disease is greater than 1.05，the risk of IVIG resistance is higher.The inflammatory factors IL-17 and IL-10 secreted by the two can assist other known indicators related to IVIG resistance in Kawasaki disease patients，improving the accuracy of predicting resistance risk.