Autoantibody profiles linked to clinical patterns in Tunisian myositis cohort

A retrospective, single-center study examined clinical and serological features in 50 Tunisian adults with myositis-specific autoantibody-positive idiopathic inflammatory myopathies. Interstitial lung disease was common in antisynthetase syndrome, while anti-SRP disease was predominantly muscle-involving and dermatomyositis-specific antibodies were associated with characteristic skin findings.

ASyS was associated with ILD in 85% of patients.
Dermatomyositis antibodies tracked with characteristic skin features.
Anti-SRP disease predominantly involved muscle.
Small, single-center retrospective cohort limits generalizability.

Idiopathic inflammatory myopathies (IIMs) encompass disorders with varied muscle and extramuscular features. In this retrospective, single-center study, researchers assessed clinical, laboratory, electromyographic and histological data in 50 adults with myositis-specific autoantibody-positive IIMs who met classification criteria. Participants had a mean age of 50.5 years, and 70% were women. The groups were antisynthetase syndrome (ASyS; 33 patients), dermatomyositis-specific antibodies (10) and anti-SRP immune-mediated necrotizing myopathy (7).

Interstitial lung disease (ILD) was reported in 85% of the ASyS group, particularly among patients with non-Jo-1 antibodies; muscle involvement was less prominent than in the other groups. Dermatomyositis-specific antibodies were associated with heliotrope rash, Gottron’s papules and skin ulcerations, as well as more frequent dysphagia. Anti-SRP myopathy was characterized by severe, predominant muscle involvement, frequent dysphagia and few extramuscular manifestations. Cancer prevalence did not differ significantly between groups, although it was numerically higher in the dermatomyositis-antibody group.

The findings support an association between antibody profiles and clinical patterns, but phenotypic overlap—particularly between ASyS and anti-MDA5-positive dermatomyositis—was also noted. The small, retrospective cohort from one center limits generalizability; these results do not establish that antibody profiles alone can determine an individual patient’s clinical course.

In practice

In adults with idiopathic inflammatory myopathy, this small Tunisian cohort found that autoantibody subgroups were associated with different patterns of organ involvement: ILD was frequent in antisynthetase syndrome, dermatomyositis-specific antibodies aligned with characteristic skin findings, and anti-SRP disease was predominantly muscle-involving. These observations may help frame clinical assessment alongside serology, but the retrospective single-center design, small subgroups and reported overlap between phenotypes limit applicability. The study does not establish diagnostic performance or support changing management on antibody profile alone.

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Source

Clinical Rheumatology: Association between clinical phenotypes and autoantibody profiles in idiopathic inflammatory myopathies: a Tunisian cohort study ↗

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