(A) Immunohistochemistry of Thymic stromal lymphopoietin (TSLP) and IgA in the tonsils of IgAN patients and non-IgAN patients with chronic tonsillitis showed the presence of TSLP and IgA-bearing cells in the follicular germinal centers (GCs), reticular crypt epithelium (Ep), and subepithelial area. Bars, 200 μm. (B, C) The number of TSLP and IgA-bearing cells in the tonsils was counted in 10 randomly chosen, low-power (100× magnification) fields for each patient. The slides were analyzed in blinded manner by two independent investigators. n = 20 for IgAN patients with Tripterygium Wilfordii treatment, n = 20 for IgAN patients without treatment and n = 20 for non-IgAN patients with chronic tonsillitis. Error bars indicate SEMs. *, P < 0.01 (Mann-Whitney U test). (D) The Y axis label on the graph (third row) showed “the number of IgA bearing cells in tonsillar GCs”, and the X axis label showed “the levels of TSLP expression in tonsillar GCs”. Correlation between IgA and TSLP was analyzed by Spearman’s correlation.