CD21(low) B cells are predictive markers of new digital ulcers in systemic sclerosis

The objective of this study was to evaluate the predictive role of CD21(low) B cells as markers of new digital ulcers in systemic sclerosis patients. Peripheral blood B cell subpopulations and clinical assessments have been evaluated in 74 systemic sclerosis patients at baseline and after a 12‐month follow‐up. After a 12‐month follow‐up, 23 (31.1%) systemic sclerosis patients developed new digital ulcers. The median percentage of CD21(low) B cells was significantly higher in patients with than without new digital ulcers [10.1 (4.3–13.6) versus 4.8 (3.5–7.4); p < 0.01]. The 10% cut‐off shows good diagnostic accuracy [area under the curve (AUC) = 0.732, confidence interval (CI) = 0.587–0.878; P = 0.01]. Kaplan–Meier curves show a significantly reduced free survival from new digital ulcers in systemic sclerosis patients with CD21(low) B cells ≥ 10% (p < 0.0001). In multivariate analysis, CD21(low) B cells ≥ 10%, modified Rodnan skin score (mRSS) and systolic pulmonary arterial pressure (sPAP) are associated with the development of new digital ulcers. We hypothesize that CD21(low) B cells are a predictive marker of new digital ulcers in systemic sclerosis patients.