CD19 and interstitial lung disease: In comparing the frequency of CD19+CD21lo/neg−CD11c+ in our CyTOF data to the frequency CD19+CD21lo/neg tBET+ population identified by fluorescence cytometry, we found that these were the same for both healthy control (49.5 ± 3.8% vs. 55.3% ± 2.7%, p = 0.43) and SSc-ILD (64.07% ± 4.5% v 61.4% ± 5.6%, p = 0.70).