Antipolymer antibodies in Danish fibromyalgia patients

OBJECTIVE: To use a new immunologic assay to investigate antipolymer antibody (APA) levels in women with fibromyalgia (FM). METHODS: The study population consisted of 35 patients with FM and 129 controls. The controls were selected based on a prior history of breast surgery and the presence or absence of a prior hospital diagnosis of soft tissue rheumatism. Study subjects underwent blood sampling, including tests for antinuclear antibodies (ANA) and APA, a clinical examination, and an interview focusing on rheumatic complaints and self-reported disability. The severity of rheumatic symptoms/signs was scored from 1 (= none) to 5 (= severe) based on the clinical examination and the interview. RESULTS: FM patients in this study represented a broad spectrum of disease severity, with the majority having mild symptoms. FM patients had a higher symptom severity and myalgic scores than controls (p < 0.001 for both variables). Adjusting for symptom severity, a weak positive association between APA levels and FM was observed (p = 0.08). The APA level was inversely associated with age, i.e., decreasing APA levels were seen with increasing age (p = 0.008). CONCLUSION: FM patients tended to have slightly higher APA levels than controls when adjusted for symptom severity. APA levels declined with age, a finding that has not been reported previously. The APA test and its clinical relevance should be evaluated in future studies.