Modifying T cell phenotypes using TYK2 inhibitor and its implications for the treatment of systemic lupus erythematosus.

OBJECTIVES: The tuning effects of JAK/TYK2 inhibitors on the imbalance between T follicular helper (Tfh) and T regulatory (Treg) cells, related to systemic lupus erythematosus (SLE) pathogenesis, were investigated using human peripheral blood samples. METHODS: Peripheral blood mononuclear cells from untreated patients with SLE and healthy controls were analysed. Tfh1 cells were identified in nephritis tissue, and the effect of Tfh1 cells on B-cell differentiation was examined by coculturing naïve B cells with Tfh1 cells. RESULTS: Tfh1 cell numbers were increased in the peripheral blood of patients, and activated Treg cell counts were decreased relative to Tfh1 cell counts. This imbalance in the Tfh to Treg ratio was remarkably pronounced in cases of lupus nephritis, especially in types III and IV active nephritis. Immunohistochemistry revealed Tfh1 cell infiltration in lupus nephritis tissues. Co-culture of Tfh1 cells (isolated from healthy individuals) with naïve B cells elicited greater induction of T-bet+ B cells than controls. In JAK/TYK2-dependent STAT phosphorylation assays using memory CD4+ T cells, IL-12-induced STAT1/4 phosphorylation and Tfh1 cell differentiation were inhibited by both JAK and TYK2 inhibitors. However, phosphorylation of STAT5 by IL-2 and induction of Treg cell differentiation by IL-2+TGFß were inhibited by JAK inhibitors but not by TYK2 inhibitors, suggesting that TYK2 does not mediate the IL-2 signalling pathway. CONCLUSIONS: Tfh1 cells can induce T-bet+ B cell production and may contribute to SLE pathogenesis-associated processes. TYK2 inhibitor may fine-tune the immune imbalance by suppressing Tfh1 differentiation and maintaining Treg cell differentiation, thereby preserving IL-2 signalling, unlike other JAK inhibitors.

Anti-survival motor neuron complex antibodies as a novel biomarker for pulmonary arterial hypertension and interstitial lung disease in mixed connective tissue disease.

OBJECTIVE: The presence of anti-U1 RNP antibodies (Abs) is critical for diagnosing MCTD. The 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: A total of 158 newly diagnosed consecutive cases of SLE, 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 analysed. 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, 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.

Usefulness of ultrasound as a predictor of elderly-onset rheumatoid arthritis with polymyalgia rheumatica-like onset.

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 analyse 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 at that time were evaluated. Synovitis was evaluated semi-quantitatively (0-3) by grey 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 rheumatoid arthritis (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 positivity, GS ≥2 of hand joints, and PD ≥1 of hand joints were independent factors with significant differences. At least one of the three factors had a sensitivity of 88.9% and specificity of 92.6%. CONCLUSIONS: The presence of at least one of the criteria: rheumatoid factor positivity, GS ≥ 2, and PD ≥ 1 of hand joints, suggested the possibility of developing EORA within 1 year of PMR diagnosis.

A case of glucocorticoid-resistant adult Still's disease complicated by pulmonary hypertension and interstitial lung disease.

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. Although she had been treated with immunosuppressive agents and pulmonary vasodilators, the ASD relapsed with fever, rash, increased inflammatory responses and exacerbated interstitial lung disease, and PH. The pathology of PH appeared to encompass groups 1 [pulmonary arterial hypertension (PAH)], 1' [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.