Unexpectedly, IL-21 failed to influence B cell apoptosis in RA patients (24.41% ± 4.82% vs. 24.30% ± 4.89%, P > 0.05; Figure 5b), whereas it was able to enhance B cell apoptosis in HC (10.21% ± 1.06% vs. 15.37% ± 2.29%, P < 0.05; Figure 5b). This evidence concerns the gene IL21 and rheumatoid arthritis.