Abstract： Objective To investigate the characteristics of immune system changes in pediatric patients with Kawasaki disease(KD)complicated with coronary artery lesion(CAL),and to provide a basis for its standardized diagnosis and treatment.Methods A total of 238 children with KD admitted to the Department of Cardiology,Hebei Children's Hospital,Hebei Province from August 2021 to May 2023 were selected as the KD group.According to CAL status,the patients were divided into CAL subgroup(61 cases)and non-CAL(NCAL)subgroup(177 cases).A total of 102 pediatric patients with fever who were diagnosed with bronchitis or upper respiratory tract infection during the same period were selected as the control group.The basic information and laboratory examination indexes of pediatric patients in each group were compared.Logistic regression method was used to analyze the risk factors of CAL in pediatric patients with KD.Based on the relevant variables,a nomogram model was established to predict the risk of CAL,and the receiver operating characteristic(ROC)curve was used to evaluate the performance of the nomogram and the predictive efficiency of each index.Results The proportion of males in the CAL subgroup was higher,the disease duration was longer,and the platelet count level was higher than those in the NCAL subgroup(all P＜0.05).The levels of interleukin-2(IL-2),IL-6,IL-10,IL-5,IL-8,complement C3,C4,and total B cells in the KD group were significantly higher than those in the control group;the levels of immunoglobulin(Ig)A,IgG,IgM,total T cells,CD8+T cells,γδT cells were lower than those in the control group;the levels of IL-2,IL-1β,interferon-α,IgA,IgG,IgM,and natural killer cells in CAL subgroups were significantly higher than those in the NCAL subgroup,while the levels of complement C3,C4,total T cells,and CD8+T cells were lower than those in the NCAL subgroup(all P＜0.05).Multivariate Logistic regression analysis showed that the decreased levels of CD8+T cells and complement C3 levels,as well as the increased levels of IgG and natural killer cell levels were independent risk factors for CAL(all P＜0.05).The prediction of CAL by the nomogram was consistent with the actual probability.The area under the curve of ROC for the combined prediction of CAL by CD8+T cells,natural killer cells,IgG,and complement C3 was 0.866(95％confidence interval:0.804-0.913),which was greater than the individual predictions of each indicator(0.800,0.631,0.653,0.651).Conclusion The changes of immune factors of natural killer cells,CD8+T cells,IgG and complement C3 is signifi-cant in patients with KD complicated with CAL,and this change may be involved in the pathogenesis of KD and CAL.