SDC1 and kidney disorder: To investigate the frequency and phenotypic characteristics of B-cells in hybrid immune kidney disease patients and controls, we determined the expression of markers for B-cell differentiation (CD27, CD38, CD24, CD20, CD138), BCR isotype (IgD, IgM, IgA, IgG), lymph node homing (CD62L) and S-specificity on live CD19+ B-cells in PBMC using flow cytometry.