Objectives Differentiation between polymyalgia rheumatica (PMR) and elderly onset rheumatoid arthritis (EORA), especially in elderly patients, is often difficult due to similarities in symptoms and serological kinetics. In this study, we aimed to analyze the predictors of EORA with PMR-like onset. Methods Seventy-two patients diagnosed with PMR, who attended our hospital for routine care and underwent musculoskeletal ultrasonography (MSUS) at that time were evaluated. Synovitis was evaluated semi-quantitatively (0-3) by gray scale (GS) and power doppler (PD) in 24 joints (both hands [wrist, metacarpophalageal, and proximal interphalangeal joints] and both shoulder joints). Results Overall, 18 patients had RA (25.0%); the mean age was 75.0 years, and 34.7% and 65.3% were male and female, respectively. In PMR and PMR/EORA groups, multivariate logistic analysis showed that rheumatoid factor (RF) positivity, GS ≥2 of hand joints, and PD ≥1 of hand joints were independent factors with significant differences. At least 1 of the 3 factors had a sensitivity of 88.9% and specificity of 92.6%. Conclusions Presence of at least one of the criteria: RF positivity, GS ≥ 2, and PD ≥ 1 of hand joints, suggested the possibility of developing EORA within 1 year of PMR diagnosis.

Objective The presence of anti-U1 RNP antibodies (Abs) is critical for diagnosing mixed connective tissue disease (MCTD). Aim of this study is to evaluate the clinical relevance of anti-survival motor neuron (SMN) complex Abs, which often coexist with anti-U1 RNP Abs. Methods 158 newly diagnosed consecutive cases of systemic lupus erythematosus (SLE), systemic sclerosis (SSc) or MCTD with anti-U1 RNP Abs were enrolled in this multicentre observational study between April 2014 and August 2022. Serum anti-SMN complex Abs were screened by immunoprecipitation of 35S-methionine-labelled cell extracts, and associations between anti-SMN complex Abs positivity and clinical characteristics were analyzed. Results Anti-SMN complex Abs were detected in 36% of MCTD patients, which was significantly higher than that in SLE (8%) or SSc (12%). Among MCTD patients classified based on the combination of the clinical features of SLE, SSc, and idiopathic inflammatory myopathies (IIM), anti-SMN complex Abs showed the highest prevalence in a subset with clinical features of all three components. Anti-SMN complex Abs-positive MCTD had a higher prevalence of pulmonary arterial hypertension (PAH) and interstitial lung disease (ILD), which are related to poor prognosis, than negative patients. Moreover, all three cases of death within 1 year of the treatment were positive for anti-SMN complex Abs. Conclusions Anti-SMN complex Abs is the first biomarker of a typical subset of MCTD which bears organ damages such as PAH and ILD.

Adult Still’s disease (ASD) is rarely complicated by pulmonary hypertension (PH). A 76 year-old woman experienced ASD relapse with repeated exacerbation of PH and interstitial lung disease (ILD). Although she had been treated with immunosuppressive agents and pulmonary vasodilators, the ASD relapsed with fever, rash, increased inflammatory responses and exacerbated ILD and PH. The pathology of PH appeared to encompass groups 1 (pulmonary arterial hypertension [PAH]), 1ʹ (pulmonary veno-occlusive disease [PVOD]), and 3. Remission induction therapy with high-dose glucocorticoid and tocilizumab was administered, and switching or adding pulmonary vasodilators was also attempted. As the disease activity of ASD decreased, the mean pulmonary arterial pressure and pulmonary vascular resistance improved. PH is an extremely rare form of organ dysfunction in individuals with ASD. Like other systemic autoimmune diseases, PH (PAH or PVOD) can determine the prognosis of ASD. Because of PH’s rarity, it is important to sufficiently evaluate its pathology, considering the possibility that PH is not clinically classified as PAH (group 1), and to administer immunosuppressive therapy and vasodilators according to the pathology.