Severe RAS-Associated Lymphoproliferative Disease Case with Increasing αß Double-Negative T Cells with Atypical Features.

Autoimmune lymphoproliferative syndrome (ALPS) is a disease of lymphocyte homeostasis caused by FAS-mediated apoptotic pathway dysfunction and is characterized by non-malignant lymphoproliferation with an increased number of TCRαß+CD4-CD8- double-negative T cells (αßDNTs). Conversely, RAS-associated leukoproliferative disease (RALD), which is caused by gain-of-functional somatic variants in KRAS or NRAS, is considered a group of diseases with a similar course. Herein, we present a 7-year-old Japanese female of RALD harboring NRAS variant that aggressively progressed to juvenile myelomonocytic leukemia (JMML) with increased αßDNTs. She eventually underwent hematopoietic cell transplantation due to acute respiratory distress which was caused by pulmonary infiltration of JMML blasts. In general, αßDNTs have been remarkably increased in ALPS; however, FAS pathway gene abnormalities were not observed in this case. This case with RALD had repeated shock/pre-shock episodes as the condition progressed. This shock was thought to be caused by the presence of a high number of αßDNTs. The αßDNTs observed in this case revealed high CCR4, CCR6, and CD45RO expressions, which were similar to Th17. These increased Th17-like αßDNTs have triggered the inflammation, resulting in the pathogenesis of shock, because Th17 secretes pro-inflammatory cytokines such as interleukin (IL)-17A and granulocyte-macrophage colony-stimulating factor. The presence of IL-17A-secreting αßDNTs has been reported in systemic lupus erythematosus (SLE) and Sjögren's syndrome. The present case is complicated with SLE, suggesting the involvement of Th17-like αßDNTs in the disease pathogenesis. Examining the characteristics of αßDNTs in RALD, JMML, and ALPS may reveal the pathologies in these cases.

Epidemiology conduction of paediatric rheumatic diseases based on the registry database of the Pediatric Rheumatology Association of Japan.

OBJECTIVES: Although epidemiological surveys of paediatric rheumatic diseases in Japan have been conducted, they were single surveys with no continuity. This is the first report of the Pediatric Rheumatology Association of Japan registry database, which was established to continuously collect data for paediatric rheumatic diseases. METHODS: Pediatric Rheumatology International Collaborate Unit Registry version 2 (PRICUREv2) is a registry database established by the Pediatric Rheumatology Association of Japan. The registry data were analysed for the age of onset, time to diagnosis, sex differences, seasonality, and other factors. RESULTS: Our data showed the same trend regarding rates of paediatric rheumatic diseases reported in Japan and other countries. The age of onset was lower in juvenile idiopathic arthritis (JIA) and juvenile dermatomyositis and higher in systemic lupus erythematosus and Sjögren's syndrome. The time to diagnosis was relatively short in JIA and systemic lupus erythematosus but longer in juvenile dermatomyositis and Sjögren's syndrome. Rheumatoid factor-positive polyarticular JIA showed a seasonality cluster with regard to onset. CONCLUSION: PRICUREv2 aided the retrieval and evaluation of current epidemiological information on patients with paediatric rheumatic diseases. It is expected that the data collection will be continued and will be useful for expanding research in Japan.

Difficulties of diagnosing idiopathic hypertrophic pachymeningitis in children: Case report and literature review.

Hypertrophic pachymeningitis (HP) is a rare inflammatory disorder characterised by local or diffuse thickening of the cranial and spinal dura mater. HP occurs owing to idiopathic or secondary causes, including autoimmune disease, infection, and trauma. HP has mainly been reported in adults, with few reported cases in children. We encountered an 11-year-old boy with idiopathic HP who presented with chronic inflammation and daily occipital headache. Gadolinium (Gd)-enhanced magnetic resonance imaging (MRI) helped us to diagnose him with HP. He was successfully treated with corticosteroids and azathioprine with no recurrence. We also conducted a literature review of childhood-onset HP and found only 16 cases, including our patient. Seven patients had idiopathic HP, and the remaining nine had secondary HP, including two with rheumatic disease. The most common clinical symptoms were headache (68.8%) and cranial nerve-related symptoms (68.8%). Inflammatory laboratory markers were elevated in 60% of patients with available data. Fifteen cases were diagnosed using Gd-enhanced MRI. The main initial treatment was steroids and/or immunosuppressants, to which 87.5% of patients responded. However, two patients with HP associated with trauma and neuroblastoma (12.5%) died, and seven patients (43.8%) had left cranial nerve-related sequelae. As the prognosis for childhood HP is poor, early diagnosis and treatment are essential. Children with headache, cranial nerve symptoms, and elevated inflammatory marker levels should be suspected of having HP and Gd-enhanced MRI should be considered.

Characteristics of persistent arthritis with refractory Kawasaki disease: a single-center retrospective study.

Arthritis is one complication of Kawasaki disease (KD); however, the clinical features of arthritis in KD have not been well clarified. We retrospectively investigated the characteristics of persistent arthritis beyond the subacute phase of KD. In this cohort, 49 of 243 patients (20%) developed arthritis, with 33 patients (14%) experiencing persistent arthritis. Among these 33 patients, 31 (94%) had complete KD. Thirty (91%) were resistant to first intravenous immunoglobulin, and 15 (45%) required additional infliximab. Five patients (15%) developed coronary artery lesions, and 24 (73%) had oligoarthritis, mainly in large lower-extremity joints. Twenty-four patients (73%) complained of arthralgia. At arthritis onset, 16 patients (48%) presented with fever, including recurrent fever in 10 patients. Serum C-reactive protein concentration in patients with active arthritis significantly increased compared with after acute KD treatment (2.4 vs. 0.7 mg/dL, p < 0.001). Serum matrix metalloproteinase-3, a biomarker of arthritis, was significantly higher in patients with active arthritis than in remission (93.7 vs. 20.3 ng/mL, p < 0.001). Thirty (91%) and 14 (42%) patients, respectively, were treated with non-steroidal anti-inflammatory drugs and prednisolone, and they completely recovered. To summarize, persistent arthritis is a common complication in refractory KD, and adequate diagnosis and treatment are necessary.

Impaired Interleukin-18 Signaling in Natural Killer Cells From Patients With Systemic Juvenile Idiopathic Arthritis.

OBJECTIVE: Systemic juvenile idiopathic arthritis (sJIA) is characterized by fever, arthritis, rash, hepatosplenomegaly, and macrophage activation syndrome; however, its pathogenesis is still unclear. Elevated serum interleukin (IL)-18 concentrations and decreased natural killer (NK) cell activity are characteristic of active disease; thus, we examined IL-18 signaling in NK cells from sJIA. METHODS: We analyzed mitogen-activated protein kinase (MAPK) p38 and nuclear factor κ light chain enhancer of activated B cells (NFκB) p65 phosphorylation in NK cells after in vitro recombinant IL-18 (rIL-18) stimulation in 31 patients with sJIA. Associations between clinical features, serum IL-18, and phosphorylation intensity were analyzed. Furthermore, we investigated the effects of high IL-18 concentrations on phosphorylation in NK cells. RESULTS: Patients were divided according to their disease activity: systemic features (n = 8), chronic arthritis (n = 7), remission on medication (n = 10), and remission off medication (n = 6). MAPK p38 and NFκB p65 phosphorylation intensity were the highest in healthy controls, followed by remission off medication, remission on medication (vs. control; MAPK p38, P < 0.01; NFκB p65, P < 0.05), chronic arthritis (P < 0.001, P < 0.001), and systemic features (P < 0.001, P < 0.001). The systemic features group showed a complete defect in phosphorylation. Serum IL-18 was the highest in the systemic features group followed by chronic arthritis, remission on medication (P < 0.01), remission off medication (P < 0.01), and healthy controls (P < 0.01). Phosphorylation intensity was negatively correlated with serum IL-18 (MAPK p38, r2  = 0.42; NFκB p65, r2  = 0.54). Furthermore, healthy control NK cells were cultured with rIL-18; impaired phosphorylation was reproduced in vitro. CONCLUSION: Impaired IL-18 signaling in NK cells correlated with disease activity in sJIA. High serum IL-18 exposure induces impaired MAPK and NFκB phosphorylation in NK cells.