IL21 and systemic sclerosis: SSc patients with a DAS28-ESR > 3.2 had more CD21low B cells (12.65% (IQR: 7.11–13.79) vs. 5.08% (IQR: 3.76–7.45), p < 0.01), higher IL-4 levels (132.98 pg/mL (IQR: 99.12–164.12) vs. 100.80 pg/mL (IQR: 62.78–121.13), p < 0.05), and higher IL-21 levels (200.77 pg/mL (IQR: 130.13–302.41) vs. 98.83 pg/mL (IQR: 35.70–231.55), p < 0.01) than patients with a DAS28-ESR ≤ 3.2.