Recent evidence suggests that type I interferon (IFN) activity has prognostic relevance in systemic lupus erythematosus (SLE). This study investigated whether combining IFN activity with elevated peripheral blood plasmablast (PB) levels—another key feature of lupus pathophysiology—improves risk stratification for poor clinical outcomes. Clinical data were prospectively collected at a single lupus center. Flow cytometry was performed on freshly isolated peripheral blood mononuclear cells to investigate Sialic acid-binding Immunoglobulin-like Lectin 1 (SIGLEC-1) as a surrogate marker of IFN activity, alongside CD19+CD20−CD27highHLA-DR+ PB frequencies. A total of 1276 samples from 121 patients were analyzed. At baseline, 48.8% of patients exhibited high IFN activity, including 27.3% with concurrent elevation in IFN and PB activity and 21.5% with isolated IFN activity. Patients with simultaneous IFN and PB activity showed higher anti-dsDNA antibody levels, were less frequently in DORIS remission (24.2% vs. 50.0%) and required higher daily prednisolone dosages (6.3 vs. 2.0 mg) than those with isolated IFN activity. During a median follow-up of 4.5 years (range 0.8–6.6), these patients experienced more flares (132 vs. 54, OR 1.42), required longer to achieve remission (median 399 vs. 140 days), and had a higher median time-adjusted prednisolone dose (5.6 vs. 3.0 mg). Concurrent elevation in IFN and PB activity identifies SLE patients with a poorer prognosis compared to isolated IFN activity. These findings suggest that combined IFN and PB assessment may improve prognostic stratification and support personalized treatment strategies in SLE.
Speidel et al. (Sat,) studied this question.