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

Objective of this study was to evaluate the predictive role of CD21low B cells as markers of new digital ulcers in systemic sclerosis patients. Peripheral blood B cells subpopulations and clinical assessment have been evaluated in 74 systemic sclerosis patients at baseline and after a 12-months follow-up. After a 12-month follow-up, twenty-three (31.1%) systemic sclerosis patients developed new digital ulcers. The median percentage of CD21low B cells was significantly higher in patients with new digital ulcers than in patients without new digital ulcers [10.1 (4.3-13.6) vs 4.8 (3.5-7.4); p<0.01]. The 10% cut-off shows good diagnostic accuracy [AUC 0.732 (IC 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 CD21low B cells≥10% (p<0.0001). In multivariate analysis, CD21low B cells≥10%, mRSS and sPAP are associated with the development of new digital ulcers. We hypotesize that CD21low B cells are a predictive marker of new digital ulcers in systemic sclerosis patients.