Clinical and Autoantibody Profile of Inflammatory Myopathies in a Mexican Cohort: A Descriptive Study

Inflammatory myopathies (IIMs) are a group of autoimmune diseases characterized by muscle inflammation and systemic features. Although autoantibody profiling has improved disease classification, regional data from Latin America remain limited.

To describe the clinical and serological characteristics of a Mexican cohort.

We conducted a cross-sectional study of adult patients who met the 2017 EULAR/ACR criteria for IIMs at a tertiary rheumatology clinic in Monterrey, Mexico, from 2015 to 2019. We interviewed patients, reviewed medical records, and performed a myositis autoantibody immunoblot panel and summarized clinical features by autoantibody positivity.

Seventy patients were included (74.3% female, mean age 44 y). Dermatomyositis was the most frequent clinical subtype (68.6%). The most common clinical features included proximal muscle weakness, Gottron's papules, and articular involvement. The most prevalent autoantibodies were anti-Ro52 (34.3%), anti-Mi2a (24.3%), and anti-PL7 (14.3%). Less common antibodies included anti-MDA5, anti-SRP, anti-TIF1γ, anti-NXP2, anti-Ku, and others, with frequencies ranging from 1.4% to 12.9%.

This study provides a detailed clinical-serological characterization of IIMs in a Mexican cohort. Our findings reinforce recognized clinico-serological phenotypes and suggest regional patterns, including the high prevalence of anti-Ro52. These results underscore the need for broader autoantibody testing and contribute to the understanding of IIM heterogeneity in underrepresented populations.