CR2 and systemic sclerosis: tBET mean fluorescence intensity was markedly increased in CD21lo/neg compared to CD21+ populations in both SSc-ILD (4110 ± 604 vs. 532 ± 90, p = 0.002) and healthy control (4019 ± 578 vs. 517 ± 27.3, p = 0.002), and most CD21lo/neg B cells were tBET positive in both healthy control and SSc-ILD (Fig. 5b, e).