IL-21 induces in vitro immunoglobulin G (IgG) and proteinase 3 (PR3)-antineutrophil cytoplasmic antibody (ANCA) production by B-cells from patients with granulomatosis with polyangiitis GPA. (A) PBMCs from ANCA-positive (n = 7) and ANCA-negative (n = 6) GPA patients were cultured in the presence of rhIL-21 and/or rh B-cell activating factor (BAFF). Culture supernatants were collected after 12 days to measure total IgG by ELISA. (B) To assess the effect of IL-21 on in vitro ANCA-production, peripheral blood mononuclear ells (PBMCs) from ANCA-positive (n = 16) and ANCA-negative (n = 12) GPA patients were stimulated in the presence of IL-21/BAFF. After 12 days, PR3-ANCA levels were determined by Phadia ImmunoCAP® 250 analyzer. P-values were calculated using the Wilcoxon matched pairs test. *P < 0.05.
Abdulahad et al. Arthritis Research & Therapy 2013 15:R70 doi:10.1186/ar4247