Anti-signal recognition particle autoantibody in patients with and patients without idiopathic inflammatory myopathy.

Abstract

OBJECTIVE:

To determine the long-term outcome and associated clinical, serologic, and pathologic features in a cohort of patients with connective tissue disease (CTD) and the anti-signal recognition particle (anti-SRP) autoantibody.

METHODS:

Sera and clinical data were collected prospectively from consecutive adult patients with polymyositis (PM; n = 134), dermatomyositis (n = 129), or other CTDs (predominantly systemic sclerosis [SSc; n = 790]). Patients were first evaluated during 1973-2001.

RESULTS:

Nineteen patients with the anti-SRP autoantibody were identified, 16 (84%) of whom had pure PM and 3 (2 with SSc and 1 with antisynthetase syndrome) had yet to develop features of myositis after a mean followup of 4.5 years (range 2.5-6 years). More SRP-positive PM patients had severe proximal muscle weakness (50%) and muscle atrophy (67%) at initial presentation compared with antisynthetase-positive PM controls. Cardiac involvement occurred in only 2 of 16 SRP-positive PM patients (13%), and interstitial lung disease was noted in 3 of 13 SRP-positive PM patients (23%) and in the 3 SRP-positive nonmyositis patients. There was a relative lack of inflammation in muscle biopsy specimens from the SRP-positive PM cohort. Other autoantibodies in the SRP-positive patients included Ro/SSA (4 patients), Th/To (1 patient), and anti-PL-12 (1 patient). Survival in the SRP-positive PM patients was comparable with that seen in the cohort of SRP-negative PM patients.

CONCLUSION:

The anti-SRP autoantibody is not specific for PM. Severe muscle weakness and atrophy were prominent features in PM patients with anti-SRP. Cardiac involvement was less common and survival was better in patients with anti-SRP than has previously been reported.

• Authors: Amy H Kao, David Lacomis, Mary Lucas, Noreen Fertig, Chester V Oddis
• Journal: Arthritis and rheumatism (Arthritis Rheum) Vol. 50 Issue 1 Pg. 209-15 (Jan 2004) ISSN: 0004-3591 [Print] United States
• PMID: 14730618 (Publication Type: Journal Article)

Chemical References

• Autoantibodies
• Signal Recognition Particle

Topics

• Adult
• Aged
• Antibody Specificity
• Autoantibodies (blood)
• Dermatomyositis (immunology, mortality, pathology)
• Female
• Humans
• Longitudinal Studies
• Male
• Middle Aged
• Muscle, Skeletal (immunology, pathology)
• Polymyositis (immunology, mortality, pathology)
• Scleroderma, Systemic (immunology, mortality, pathology)
• Signal Recognition Particle (immunology)