Photo Credit: ttsz

The following is a summary of “Type I interferon biomarker in idiopathic inflammatory myopathies: associations of Siglec-1 with disease activity and treatment response,” published in the November 2024 issue of Rheumatology by Kamperman et al. 

Researchers conducted a prospective study to examine the expression of Siglec-1, a type I interferon biomarker, in adult patients with idiopathic inflammatory myopathies (IIM). 

They analyzed PBMC samples from 19 newly diagnosed adult patients with IIM and 9 healthy controls. Siglec-1 expression on monocytes was measured by flow cytometry before and after intravenous immunoglobulin (IVIG) monotherapy. The expression was evaluated in relation to the IIM subtype, physician global activity (PhGA) scores, manual muscle strength (MMT), and the Total Improvement Score (TIS). 

The results showed that all patients exhibited increased Siglec-1 expression at baseline, with the highest relative median fluorescence intensity observed in patients with dermatomyositis (DM). After 9 weeks, follow-up samples were available for 15 patients, of whom 10 showed a decline in Siglec-1 expression. In DM, Siglec-1 expression significantly correlated with disease activity, including MMT (rs = -0.603, P = 0.013), PhGA (rs = 0.783, P < 0.001), and the TIS (rs = -0.786, P = 0.036). 

They found that Siglec-1 expression was increased in treatment-naive IIM and declined after IVIG monotherapy. The study highlighted the potential of Siglec-1 as a dynamic biomarker, particularly in DM, warranting further validation in larger cohorts with extended follow-up. 

Source: academic.oup.com/rheumatology/advance-article/doi/10.1093/rheumatology/keae630/7905153