Abstract: OBJECTIVE To explore the effect of acute respiratory tract infection on expression of peripheral blood B lymphocyte core 1β3 galactosyltransferase chaperone protein（Comsc）and abnormal glycosylation of immunoglobulin molecules in children with IgA nephropathy（IgAN）. METHODS A total of 80 children with IgAN who were treated in the pediatrics department of Xinxiang Central Hospital from Nov 2015 to Nov 2019 were enrolled in the study and divided into the infection group with 46 cases and the no infection group with 34 cases according to the status of acute respiratory tract infection within 1 month before the renal biopsy. The expression of B lymphocyte Comsc, immunoglobulin（Ig） A1 level and binding capacity of IgA1 molecule and vicia villosa lectin were compared between the two groups of children, and the values of expression of B lymphocyte Comsc, IgA1 level and binding capacity of IgA1 molecule and vicia villosa lectin in diagnosis of the infection were analyzed. RESULTS The Comsc mRNA and expression level of proteins of the infection group were significantly lower than those of the no infection group（P＜0.05）. The IPS score, IgA1 level and binding capacity of IgA1 molecule and vicia villosa lectin of the infection group were significantly higher than those of the no infection group（P＜0.05）. Receiver operating characteristic（ROC） curves showed that the Comsc mRNA, Comsc protein, IgA1 and binding capacity of IgA1 molecule and vicia villosa lectin had certain value in diagnosis of the infection in the IgAN children, the diagnostic value of the Comsc mRNA was the highest, AUC of the joint detection of above indexes was 0.943 in diagnosis of the infection, higher than that of the single index. CONCLUSION The acute respiratory tract infection plays an important role in pathogenesis of IgAN, and its regulating mechanism may affect the expression of Comsc and abnormal glycosylation of immunoglobulin molecules.