Interstitial lung disease (ILD) is a serious complication of systemic sclerosis (SSc) with a variable clinical trajectory.1 Both clinical and biological factors can provide prognostic information on the risk of progression of ILD; however, prognostic biomarkers do not consistently predict outcomes in patients receiving different treatments for SSc-ILD.2 In the present issue of Thorax, Guler et al demonstrate that persistent elevation in C reactive protein (CRP) is associated with an increased risk of mortality in 1171 patients with SSc-ILD.3 Notably, in this observational study, treatment with immunosuppressive therapy (defined as use of cyclophosphamide, mycophenolate mofetil, methotrexate, azathioprine, rituximab or prednisone >10 mg per day at any visit during the follow-up period) in patients with SSc-ILD with a persistent inflammatory phenotype (defined as CRP values≥5 mg/L at ≥80% of visits;) was associated with stabilisation of the course of forced vital capacity (FVC)% predicted; whereas, lack of treatment with immunosuppressive therapies was associated with a decline in FVC% predicted in this subgroup. These important findings are consistent with the results of prior randomised controlled trials in SSc-ILD demonstrating improvement or stabilisation of the FVC course in patients receiving various immunosuppressive therapies, including mycophenolate,4 cyclophosphamide,4 5 rituximab6 7 and tocilizumab.8

The study of Guler et al also found that SSc patients with a persistent inflammatory phenotype were more …