Features of BAFF and APRIL receptors on circulating B cells in antineutrophil cytoplasmic antibody-associated vasculitis.

To investigate the features of circulating B cells, their expressing receptors, serum levels of B-cell activation factor of the TNF family (BAFF), and a proliferation-inducing ligand (APRIL) in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Blood samples from 24 patients with active AAV (a-AAV), 13 with inactive AAV (i-AAV), and 19 healthy controls (HC) were included in this study. The proportion of B cells and their expressing BAFF receptor (BAFF-R), transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), and B-cell maturation antigen were analyzed via flow cytometry. Serum levels of BAFF, APRIL, and interleukin (IL)-4, IL-6, IL-10, and IL-13 were also evaluated using an enzyme-linked immunosorbent assay. The proportion of plasmablasts (PB)/plasma cells (PC) and serum levels of BAFF, APRIL, IL-4, and IL-6 were significantly higher in a-AAV than in HC. Higher serum levels of BAFF, APRIL, and IL-4 were observed in i-AAV than in HC. Lower expression of BAFF-R on memory B cells and higher expression of TACI on CD19+ cells, immature B cells, and PB/PC were demonstrated in a-AAV and i-AAV than in HC. The population of memory B cells was positively associated with serum APRIL levels and BAFF-R expression in a-AAV. In conclusion, decreased expression of BAFF-R on memory B cells and increased expression of TACI on CD19+ cells, immature B cells, and PB/PC, as well as increased serum levels of BAFF and APRIL, were sustained even in the remission phase of AAV. Persistent aberrant signaling of BAFF/APRIL may contribute to disease relapse.

Immunopathological features of myopathy associated with small-to-medium-sized vessel vasculitis and differences from autoimmune myositis.

OBJECTIVES: Patients with systemic vasculitis may develop myalgia as an initial symptom. However, the immunopathology of vasculitic myopathy remains unclear. We investigated the immunopathological features of skeletal muscle in small-to-medium-sized vessel vasculitis. METHODS: We analysed muscle tissue biopsies from 15 patients with vasculitis, including antineutrophil cytoplasmic antibodyassociated vasculitis and polyarteritis nodosa, and 15 patients with autoimmune myositis (AIM), including polymyositis and immune-mediated necrotising myopathy, as comparison disease controls. Immunohistochemical staining for CD56/neural cell adhesion molecule (NCAM), major histocompatibility complex class I, C5b-9/membrane attack complex (MAC), and CD31 was performed. The vascularity score was defined as the total number of CD31-expressing blood vessels. The association between CD56/NCAM-expressing myofibers and clinical findings was evaluated in patients with vasculitis. RESULTS: Patients with vasculitis had a significantly lower frequency of CD56/NCAM-expressing myofibers than those with AIM and a positive correlation between the frequency of CD56/NCAM-expressing myofibers and serum aldolase levels. Patients with vasculitis had significantly fewer major histocompatibility complex class I-expressing myofibers and C5b-9/MAC deposits on the sarcolemma than those with AIM. C5b-9/MAC deposits in blood vessels were observed in >70% of patients with vasculitis. Patients with vasculitis had significantly higher vascularity scores in the endomysium than those with AIM. CONCLUSIONS: Patients with vasculitis demonstrated mild myofiber damage based on the lower involvement of CD56/NCAM-expressing myofibers compared to those with AIM. Complement component deposits on the vessel walls and hypervascularity in the endomysium areas may be immunopathological features of vasculitic myopathy.

Elucidation of abductor digiti minimi activity in chronic ankle instability.

[Purpose] This study aimed to compare the muscle activity around the foot and ankle joints, notably of the abductor digiti minimi, between affected and unaffected sides of individuals with chronic ankle instability. [Participants and Methods] Twelve adult males with chronic ankle instability in one ankle (age, 27.7 ± 5.4 years; height, 172.5 ± 8.1 cm; weight, 67.5 ± 8.1 kg) were included and underwent surface electromyography assessments in multiple positions on both affected and unaffected sides. Measurements were obtained for eight muscles including the abductor digiti minimi. Each measurement included a 5-s segment of the stable waveform, with the root mean square-processed and normalized to the resting position set to 1. [Results] Abductor digiti minimi activity on the affected side was significantly reduced during maximal toe extension/abduction with both ankle dorsiflexion and plantarflexion. Peroneus longus activity on the affected side was significantly greater during maximal toe extension/abduction with ankle plantarflexion; peroneus longus and tibialis anterior muscle activities were significantly greater on the affected side during maximal toe extension/abduction with ankle dorsiflexion. [Conclusion] In the absence of load, muscle imbalance in the intrinsic and extrinsic muscles of the foot was suggested. However, no significant differences were observed under loading conditions.

Low serum complements in idiopathic inflammatory myositis: clinical features and impact on the prognosis.

This study investigated the clinical features and prognostic relevance of decreased serum complement levels in patients with idiopathic inflammatory myositis (IIM). The clinical information of IIM patients with less than normal serum complement levels (L-Com) and that of those with normal serum complement levels (N-Com) was compared. In patients with interstitial lung disease (ILD), regression analyses were used to investigate the implication of L-Com in their PaO2/FiO2 (P/F) ratio. Prognostic outcomes of ILD were evaluated using the log-rank test. Of 94 IIM patients, 26 with L-Com (median age, 56.0 years) and 68 with N-Com (56.5 years) were included. The prevalence of women was significantly higher in patients with L-Com (92.3%) than in those with N-Com (67.6%). ILD was observed in 17 (65.4%) patients with L-Com and in 46 (67.6%) with N-Com. Among patients with ILD, the P/F ratio was significantly lower in those with L-Com than in those with N-Com. Serum C3 levels were correlated with decreased P/F ratio. Inferior prognosis of ILD was significantly demonstrated in patients with L-Com, especially in those positive for anti-melanoma differentiation-associated protein 5 antibody. L-Com may be implicated in reduced arterial oxygen levels and a poorer prognosis in patients with IIM-related ILD.

Early skeletal muscle manifestations in polyarteritis nodosa and ANCA-associated vasculitis.

Skeletal muscle involvement is common in patients with small- and medium-sized vasculitis, particularly polyarteritis nodosa (PAN) and antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Despite being not included in the standard classification criteria for PAN and AAV, skeletal muscle involvement is an important clinical indicator, particularly when vasculitic myopathy is the only pathological evidence in the absence of other organ involvement. Herein, we comprehensively reviewed and compared the clinical features of 71 and 135 patients with PAN and AAV, respectively, with skeletal muscle involvement at the time of disease onset. Most patients with PAN and AAV exhibited skeletal muscle involvement, often characterized by myalgia and occasional muscular weakness, predominantly in the lower extremities. Myalgia and weakness were observed more frequently in the distal lower extremities in patients with PAN than in those with AAV. In contrast, skeletal muscle involvement tended to exhibit a more dispersed distribution across all four extremities in those with AAV. Muscle magnetic resonance imaging T2-weighted and short-tau inversion recovery sequences can effectively identify hyperintense areas attributed to hypervascularity of affected muscle tissues and serve as a sensitive and useful modality for visually determining the suitable biopsy site. >90% of patients with PAN and AAV demonstrated perivascular inflammation in their affected muscle tissues, whereas fibrinoid necrosis of the vessel walls was reported in two-thirds of patients. Serum creatine kinase (CK) levels were within the normal range in approximately 80% of patients presenting with skeletal muscle involvement in PAN and AAV. Furthermore, muscle fiber damage was milder in patients with skeletal muscle involvement in PAN and AAV than those with idiopathic inflammatory myositis. Meanwhile, serum CK levels were elevated in 65-85% of patients with PAN and AAV who had myofiber necrosis and degeneration in the affected muscles. Most patients with PAN and AAV showed improvement in skeletal muscle involvement following glucocorticoids (GCs) administration; however, relapse was observed in some patients during the tapering of GCs. In summary, skeletal muscle involvement is a potential indicator for establishing PAN and AAV diagnoses during the early phases of the disease.

Testicular vasculitis in eosinophilic granulomatosis with polyangiitis: a case-based review.

Testicular vasculitis (TV) develops when an organ is involved in systemic vasculitis. A 47-year-old man with eosinophilic granulomatosis with polyangiitis (EGPA) developed TV as the first clinical episode. The patient had bronchial asthma for 8 years and developed left testicular pain before developing arthralgia, abdominal involvement, and sensory polyneuropathy, which led to the diagnosis of EGPA. The induration of the affected testicle persisted even after initiating immunosuppressive therapy with corticosteroids and cyclophosphamide, raising concern for testicular neoplasm, while testicular pain and other symptoms resolved. The patient underwent inguinal orchiectomy, and a histology examination of the resected testicle revealed fibrinoid necrotizing vasculitis. Only three cases of biopsy-proven TV in patients with EGPA have been reported in our review of published English-language articles. Two of the three patients in the reviewed cases developed TV before being diagnosed with EGPA. Moreover, all patients underwent extirpation of the affected testicle, leading to a pathological diagnosis of TV. This report suggests that TV may develop and be the presenting condition in EGPA, although urogenital involvement is rare.

Hypertrophic pachymeningitis in polyarteritis nodosa: a case-based review.

Hypertrophic pachymeningitis (HP) is a rare neurological disorder with focal or diffuse thickening of the dura mater, which usually causes headache, cranial neuropathies, seizures, and motor or sensory impairments. The development of HP is attributed to an immune-mediated mechanism, and some autoimmune diseases have been implicated in the development of HP. Herein, we describe the case of a 73-year-old woman with persistent headache ascribable to HP, which developed approximately 3 years after a diagnosis of polyarteritis nodosa (PAN). She was treated with high-dose corticosteroid and cyclophosphamide that resulted in immediate disappearance of headache and improved radiological findings of thickened dura mater. In addition, she was subsequently administered methotrexate, ultimately resulting in maintenance of remission and regular reduction of prednisolone. In our review of published English articles, only two cases of HP in patients with PAN have been reported to date, suggesting that HP is a rare complication in PAN. However, it should be recognized that HP may develop as a neurological involvement related to PAN.

IgG4-related Disease with a Cardiac Mass Causing Cerebral Infarction.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic inflammatory disease characterized by infiltration of extensive IgG4-positive plasma cells and lymphocytes. Although IgG4-RD has been observed in almost all organs, it rarely affects the myocardium. Cardiovascular lesions of IgG4-RD appear as aortic (aortic aneurysm and aortitis) and pericardial (constrictive pericarditis) lesions as well as pseudotumors around the coronary arteries. We herein report a case of IgG4-RD with a cardiac mass in the right atrium involving a sinus node. This condition caused arrhythmia and repeated strokes. We successfully treated the patient through resection of the cardiac mass, catheter ablation and immunosuppressive therapy.

Clinical characteristics and treatment of elderly onset adult-onset Still's disease.

Adult-onset Still's disease (AOSD)-a systemic inflammatory disease-often occurs at a young age. Recently, elderly onset patient proportion has been increasing; however, data are limited. To evaluate the characteristics of elderly patients with AOSD in a multicenter cohort, we retrospectively analyzed 62 patients with AOSD at five hospitals during April 2008-December 2020. Patients were divided into two groups according to age at disease onset: younger-onset (≤ 64 years) and elderly onset (≥ 65 years). Clinical symptoms, complications, laboratory findings, treatment, and outcomes were compared. Twenty-six (41.9%) patients developed AOSD at age ≥ 65 years. The elderly onset group had a lower frequency of sore throat (53.8% vs. 86.1%), higher frequency of pleuritis (46.2% vs. 16.7%), and higher complication rates of disseminated intravascular coagulation (30.8% vs. 8.3%) and macrophage activation syndrome (19.2% vs. 2.8%) than the younger onset group. Cytomegalovirus infections were frequent in elderly onset patients (38.5% vs. 13.9%) but decreased with early glucocorticoid dose reduction and increased immunosuppressant and tocilizumab use. Elderly AOSD is not uncommon; these patients have different characteristics than younger-onset patients. Devising a way to control disease activity quickly while managing infections may be an important goal in elderly AOSD.

Oxidative Stress Promotes Instability of Regulatory T Cells in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

We investigated the characteristics of regulatory T cells (Tregs), focusing on the relationship between their stability and reactive oxygen species (ROS), in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Intracellular expressions of effector cytokines, forkhead box protein 3 (FoxP3), ROS, phosphorylated mammalian target of rapamycin (mTOR), and sirtuin 1 (SIRT1) in Tregs from peripheral blood mononuclear cells (PBMCs) of patients with AAV and healthy controls (HC) were analyzed. The alterations in and functional ability of Tregs were compared before and after resveratrol (RVL) treatment of PBMCs in patients with AAV. Significantly higher expressions of interferon (IFN)-γ, interleukin (IL)-17, IL-4, ROS, and phosphorylated mTOR (pho-mTOR) and lower expression of SIRT1 in CD4+CD25+FoxP3+ cells were found in patients with AAV than in the HC. FoxP3 expression in CD4+CD25+ cells and suppressive function of Tregs were significantly lower in patients with AAV than in the HC. Tregs after RVL treatment demonstrated significant decreases in IFN-γ, ROS, and pho-mTOR levels and increases in FoxP3, SIRT1 levels, and functional activity. Conversely, the direct activation of SIRT1 by SRT1720 resulted in decreased FoxP3 expression, with no reduction in ROS levels. The pho-mTOR levels were significantly higher in Tregs after activation by SRT1720 than in those after RVL treatment. This study suggested that imbalanced changes in Tregs could be attributed to mTOR activation, in which ROS overproduction was predominantly implicated. Therefore, ROS is a key mediator for promoting Tregs instability in AAV.