# Clinical Characteristics of Patients With Anti‐Signal Recognition Particle Antibody: A Cohort Study

## TL;DR

This study examines the clinical features and treatment of patients with anti-SRP antibodies, revealing a varied disease spectrum and high rates of coexisting autoantibodies.

## Contribution

The study provides new insights into the clinical management and heterogeneous features of patients with anti-SRP antibodies in routine clinical practice.

## Key findings

- Many patients with anti-SRP antibodies did not present with myositis features.
- Interstitial lung disease was common, affecting 53% of patients.
- High rates of coexisting myositis-specific and antinuclear autoantibodies were observed.

## Abstract

Anti‐signal recognition particle (anti‐SRP) antibodies are myositis‐specific autoantibodies associated with immune‐mediated necrotizing myopathy. This study was undertaken to better understand how patients with anti‐SRP antibodies have been managed at our tertiary centre and to assess the spectrum of clinical features and outcomes in routine clinical practice.

We conducted a retrospective evaluation of 25 patients with anti‐SRP antibodies identified via line‐blot immunoassay at a tertiary care centre (2019–2024). Demographic, clinical, serological, and imaging data were reviewed.

The group of patients had a mean age of 60.1 years, with a female‐to‐male ratio of 10:15. Eight patients (32%) were diagnosed with myositis, primarily presenting with proximal muscle weakness. Interstitial lung disease was observed in 53% of the group of patients, and 50% of the subset of patients with myositis. Coexisting myositis‐specific autoantibodies were present in 32%, and 48% had positive antinuclear antibody titres (≥ 1:400). Cardiac involvement was reported in two myositis patients. Corticosteroids, often combined with mycophenolate mofetil or other immunosuppressants, formed the basis of treatment.

Anti‐SRP antibodies are associated with a heterogeneous clinical spectrum, with many patients lacking myositis features. There was a high prevalence of coexisting autoantibodies. Further studies are needed to elucidate the pathogenic role of anti‐SRP and optimise management strategies.