CD21low B cells in systemic sclerosis: a possible marker of vascular complications

Objectives: To evaluate expansion of CD21low B cells and their role in B cell homeostasis, apoptosis, clinical manifestations and serum vascular endothelial growth factor (VEGF) in systemic sclerosis (SSc). Materials and methods: B-cells subpopulations and apoptosis have been assessed in 74 SSc patients and 20 healthy donors. Renal Doppler ultrasound, echocardiography, pulmonary function test and VEGF were performed. Results: SSc patients with expanded CD21low B cells (SSc-CD21low) show a distinct B cell profile with increased memory B cells compared to patients without CD21low B cells (SSc-CD21+). Renal resistive index, systolic pulmonary arterial pressure and FVC/DLCO ratio were significantly higher in SSc-CD21low group than SSc-CD21+, DLCO was lower in SSc-CD21low group than SSc-CD21+. We found a positive linear correlation between CD21low and sPAP, RI and FVC/DLCO ratio whereas a negative correlation was observed between CD21low and DLCO and VEGF levels. Conclusions: CD21low B cells are increased in SSc patients with visceral vascular manifestations.