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

Objectives: To evaluate expansion of CD21(low) 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 CD21(low) B cells (SSc-CD21(low)) show a distinct B cell profile with increased memory B cells compared to patients without CD21(low) B cells (SSc-CD21(+)). Renal resistive index, systolic pulmonary arterial pressure and FVC/DLCO ratio were significantly higher in SSc-CD21(low) group than SSc-CD21(+), DLCO was lower in SSc-CD21(low) group than SSc-CD21(+). We found a positive linear correlation between CD21(low) and sPAP, RI and FVC/DLCO ratio whereas a negative correlation was observed between CD21(low) and DLCO and VEGF levels. Conclusions: CD21(low) B cells are increased in SSc patients with visceral vascular manifestations.