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

Abstract

Background: 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.

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

Methods: 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.

Results: 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%.

Conclusions: 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.