The findings of musculoskeletal ultrasonography on primary Sjögren's syndrome patients in childhood with articular manifestations and the impact of anti-cyclic citrullinated peptide antibody.

Objective: We researched the findings of musculoskeletal ultrasound sonography (MSUS) on primary Sjogren's syndrome in childhood (pSS-C) with articular manifestations. The correlation of rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACPA) were investigated to evaluate the usefulness of MSUS on their articular prognosis. Method: The objective patients are pSS-C cases who visited our hospital complaining joint pain and/or joint swelling and for whom MSUS was performed. Result: Eight patients included 6 female and 2 male, 5 RF-positive patients and 3 ACPA- positive patients. The mean age of onset was 11.1 ± 3.0 years (352 physical joint findings and 284 MSUS findings. The number of joints found clinical articular manifestations was 58/352 joints, and arthritis detected by MSUS was 30/284 joints). In multivariate analysis, the odds ratio of clinical articular manifestations was significant high in RF-positivity (2.9, 95%CI 1.5-6.2). The odds ratio of arthritis detected by MSUS in ACPA-positivity was significant high (3.7, 95%CI 1.5-11.6), although odds ratio in RF-positivity had no statistical significance and a similar trend was seen in odds ratios of subclinical arthritis (4.9, 95%CI 1.6-18.0). Conclusion: It was indicated that MSUS is useful for pSS-C. ACPA-positive pSS-C patients have arthritis and subclinical arthritis more frequently than ACPA-negative patients.