CD19 and Abnormal renal physiology: In a previous study [30], we proposed that β1,3-galactosyltransferase (β3GalT) may be an important enzyme responsible for regulating the post-translational carbohydrate modification of IgA in tonsillar CD19-positive B cells in patients with IgAN, since a decrease in the expression of the β3GalT gene was significantly correlated with renal dysfunction, the degree of proteinuria, and the severity of the renal injury score.