Regulatory B cell imbalance correlates with Tfh expansion in systemic sclerosis
Laure Ricard, Florent Malard, Sébastien Rivière, Charlotte Laurent, Olivier Fain, Mohamad Mohty, Béatrice Gaugler, A. Mékinian
Abstract
We previously identified an expansion of functional and activated circulating T follicular helper (cTfh) cells in SSc patients. The aim of this study was to analyse the frequency of regulatory B (Breg) cell subsets and the correlation with Tfh in SSc patients. Methods. Circulating Breg cells CD24 h iCD38 hi and CD27 + CD24 hi levels and cTfh cells CD4 + CXCR5 + PD1 + were determined by cytometry in 50 SSc patients and 32 healthy subjects. Results. The frequency of Breg cells CD24 hi CD38 hi and CD24 hi CD27 + was significantly reduced in patients with SSc as compared to controls (p=0.02 and p<0.001, respectively). In contrast, when examining the CD21 low B cell subset, the frequency was significantly increased in SSc patients compared to healthy controls, (p<0.001). There was no difference in Breg cell levels in patients with diffuse SSc and limited SSc. However, CD24 hi CD27 + Breg cell frequency was significantly decreased in SSc patients with pulmonary arterial hypertension (p=0.014), but not in patients with interstitial lung disease (p=0.058). Furthermore, we observed a negative correlation between cTfh and CD24 hi CD27 + Breg cell levels in SSc patients but not in healthy controls (p=0.02).