Mechanism of Yiqi Yangying Heluo Formula in the Treatment of IgA Nephropathy by Affecting Gd‐IgA1 Based on BAFF Molecular Level and T Lymphocyte Immunity

Background. Galactose‐deficient IgA1 (Gd‐IgA1) is a critical initiating factor in the pathogenesis of IgA nephropathy (IgAN), which plays an important role in the diagnosis and evaluation of this disease. Moreover, the whole pathogenesis process has an intimate association with the immune response of T and B lymphocytes and their inflammatory factors. There is no specific therapy for IgAN at present. Yiqi Yangyin Formula can significantly reduce urinary protein and hematuria in patients with IgAN. Yiqi Yangying Heluo Formula (YYHF) is optimized on the basis of the above prescription, but its specific mechanism remains to be further studied. Methods. The effect of YYHF on urinary protein and urinary red blood cell count in patients with IgAN was observed by a self‐controlled clinical study before and after treatment. On this basis, flow cytometry was used to detect the proportion of T lymphocyte subsets in peripheral blood of patients with IgAN before and after treatment and healthy controls. Meanwhile, the levels of Gd‐IgA1, B cell activation factor (BAFF), and their cytokines (IL‐4, IL‐6, and IL‐17) in peripheral blood were detected by enzyme‐linked immunosorbent assay. The changes in mechanism‐related indicators of the two groups were observed and subject to correlation analysis. Results. (1) Compared with the levels before treatment, 24‐hour urinary protein content decreased by 47.7% and urinary red blood cell number decreased by 67% in patients with IgAN intervened by YYHF after 48 weeks of follow‐up. (2) Compared with the healthy control group, patients with IgAN showed a significantly increased proportion of Th1 cells, Th17 cells, Th1/Th2, Th1/Treg, Th2/Treg, and Th17/Treg, obviously reduced proportion of Th2 cells and Treg cells, and evidently elevated levels of Gd‐IgA1, BAFF, and their cytokines (IL‐4, IL‐6, and IL‐17) in the peripheral blood. (3) Following 48 weeks of follow‐up after intervention treatment with YYHF, the levels of Gd‐IgA1, BAFF, IL‐6, and IL‐17 were significantly lower, but the level of IL‐4 was higher in peripheral blood of patients with IgAN than those before treatment and after 24 weeks of treatment; simultaneously, the proportion of Th1 cells, Th17 cells, Th1/Th2, Th1/Treg, Th2/Treg, and Th17/Treg decreased while that of Th2 cells and Treg cells increased after 48 weeks of follow‐up compared with that before treatment in peripheral blood of patients with IgAN. (4) The results of correlation analysis revealed that the level of Gd‐IgA1 in peripheral blood of patients with IgAN was positively correlated with the level of BAFF, as well as the proportion of Th1 cells, Th17 cells, Th1/Th2, IL‐6, and IL‐17 levels, and negatively correlated with the proportion of Treg cells. In addition, the level of Gd‐IgA1 in peripheral blood was positively correlated with proteinuria, yet without correlation with hematuria. Conclusion. YYHF can reduce the quantitative level of 24 h urinary protein and urinary red blood cell count in patients with IgAN. Patients with IgAN have obvious T cell immune imbalance. YYHF can significantly reduce the level of Gd‐IgA1 in patients with IgAN, and its mechanism may be explained by the reduced level of BAFF in peripheral blood and improved immune balance of T cells.