B cell depletion with rituximab (anti-CD20) has not consistently demonstrated benefit in patients with fibrotic ILD in controlled studies (82–84), however substantial clinical activity in SSc was anecdotally reported with CD19-directed CAR-T or anti-CD3/CD19 T cell engager treatment, albeit in open-label investigations of small numbers of patients with limited follow-up and potentially concerning toxicity (85–87). Here, CD19 is linked to interstitial lung disease.