Fig. 1

MZB1 is a highly expressed protein in lymph nodes from SLE patients. a Volcano plot showing distribution of all proteins in lymph nodes from SLE patients (n = 3) and controls (n = 3) analyzed by LC-MS. Horizontal line denotes fold change. Vertical line represents p value (ANOVA). Differences > 1.5-fold change and p ≤ 0.05 considered statistically significant. Fold-change values indicate higher (+) and lower (–) expression in SLE patients compared with controls. Significant proteins labeled with their gene name. b Representative immunoblotting for MZB1 in lymph node tissue from SLE patients and controls. Right: Quantification of the immunoblot (n = 3 each). Mean band intensity ratio measured as the intensity of the MZB1 band divided by intensity of the corresponding beta-actin band. Error bars indicate SEM. c Upper: histological section of an axillary lymph node from SLE patients showing reactive follicular hyperplasia. HE, scale bar = 100 μm. Middle: MZB1 immunostaining of the same sample of the upper image, showing numerous positive cells in the interfollicular area and within the germinal center. Scale bar = 50 μm. Lower: MZB1 immunostaining of the control. Scale bar = 50 μm. d MZB1⁺ cells in lymph nodes from SLE patients were significantly more frequently observed in the germinal center and interfollicular areas compared with those from controls. *p<0.05; **p<0.01 HPF high-power field, SLE systemic lupus erythematosus