BackgroundIgA nephropathy (IgAN) is a common primary renal disease in childhood.MethodsTwenty blood samples and renal tissue from patients with IgAN, 20 blood samples from healthy children and 10 normal renal tissue were collected. Serum Gd-IgA1 and renal Gd-IgA1, CD31, α-SMA and vimentin were measured.ResultsThe serum Gd-IgA1 concentration in the IgAN group was significantly higher. Gd-IgA1 was not expressed in normal kidneys, which was positive in the IgAN group. Gd-IgA1 levels in serum and renal tissue were not related. The expression of CD31 decreased significantly in IgAN group, while the expression of α-SMA and vimentin increased significantly. There was no significant correlation between the renal concentration of Gd-IgA1 and CD31, α-SMA and vimentin.ConclusionThe increased Gd-IgA1 in the serum and kidney may promote the pathogenesis of IgAN. The serum Gd-IgA1 cannot predict the extent of its deposition in the kidney. Endothelial mesenchymal transition (EndMT) may be involved in the pathogenesis of renal fibrosis in IgAN.