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Course of anti-Jo-1+ patients with antisynthetase syndrome is variable, often incomplete
The course of disease in patients with antisynthetase syndrome and anti-Jo-1 antibodies is variable and often presents in an incomplete form or with a predominant feature such as arthritis, myositis or interstitial lung disease, according to the results of a study anti-Jo-1-positive patients.
A cohort of 225 patients with antisynthetase syndrome (ASSD) and anti-Jo-1 antibodies, including 167 women, from 24 rheumatology centers in Germany, Italy, Spain and the U.S. were studied. Patients had at least two positive anti-Jo-1 antibody tests and one or more manifestation arthritis, myositis or interstitial lung disease (ILD). Regular follow-up screening for ILD, muscle enzymes and other diagnostics were performed over a median follow-up duration of 88.5 months.
Joint symptoms of arthritis and fever, mechanic’s hands and Raynaud’s syndrome (RS) were observed in 64.5% of patients which was polyarticular and symmetrical in 67% of symptomatic patients. Of 139 patients with available data, 31.5% were rheumatoid factor (RF) and immunoglobulin-M (IgM) positive. Anti-cyclic citrullinated peptide antibodies (ACPA) were found in 15 of 109 patients with available data. In 74 patients without arthritis, six were RF- and IgM-positive while ACPA was positive in one of 60 patients. Anti-Ro antibodies were present in 118 of 219 patients.
Myositis was observed in 55.5% of the patients and ILD was present in 51%, 40% of which were acute cases, 37% were chronic and 23% patients with ILD were asymptomatic.
Overall, RS was the first symptom present in nine patients and was ultimately present in 52 of 221 patients, and fever was detected in 57 o 222 patients. Mechanic’s hands were observed in 42 of 217 patients.
Complete ASSD was present in 19.5% of all patients and 49% had one onset finding, including arthritis in 49% of the subset. Of 71 patients (31.5%) with incomplete forms of ASSD, 39.5% had both arthritis and myositis, 35.5% had ILD and myositis and 25% had arthritis and ILD.
The diagnostic delay following the detection of anti-Jo-1 antibodies was a median of 6 months, with no statistically significant differences seen between complete and incomplete forms. No significant differences in age were observed between patients with complete or incomplete forms of ASSD, but anti-Ro-positive patients were more common in patients with incomplete forms of ASSD.
“Our study suggests that anti-Jo-1 antibodies positivity should be ruled out in all patients presenting with isolated myositis, ILD and arthritis, even though other diagnoses are possible,” the researchers concluded. “The clinical implication of anti-Jo-1 positivity in these patients is relevant because it may be a predictor of the ex novo occurrence of further manifestations during follow-up.” – by Shirley Pulawski
Disclosure: The researchers report no relevant financial disclosures.