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.

Genetic analysis of human parechovirus type 5 isolated from children in Sapporo, Japan in the summer of 2018.

Human parechovirus (HPeV) types 1 and 3 are frequently detected in Japan, but HPeV5 is not detected. HPeV5 was isolated for the first time in Japan from seven clinical samples collected from children in Sapporo as part of the National Epidemiological Surveillance of Infectious Diseases from July to August in 2018. Seven HPeV5 strains that were detected in Sapporo (HPeV5 Sa) were analyzed in the VP1 region by direct sequencing using Sanger sequencing methods. Whole genome sequence of these strains was determined by next-generation sequencing. The VP1 region of HPeV5 Sa was closely related to HPeV5 strains detected in Belarus and Germany in 2018, and to those detected in Australia in 2019. The 3D polymerase region of HPeV5 Sa strains showed a high nucleotide identity to HPeV3 strain detected in Australia in 2013. These findings suggest that HPeV5 Sa is a recombinant virus of HPeV5 and HPeV3, and HPeV5 strains that are genetically closely related to each other may have circulated in Europe, Japan, and Australia between 2018 and 2019.

External validation of the EULAR/ACR idiopathic inflammatory myopathies classification criteria with a Japanese paediatric cohort.

OBJECTIVES: To assess the performance of the EULAR/ACR idiopathic inflammatory myopathies (IIMs) classification criteria to classify juvenile IIMs (JIIMs) in an Asian paediatric population. METHODS: Sixty-eight JIIM patients and 49 non-JIIM patients diagnosed at seven major paediatric rheumatology centres in Japan between 2008 and 2015 were enrolled. Retrospective data were collected, and each patient's data form was submitted. The expert group reviewed the forms and re-examined the diagnoses. The EULAR/ACR criteria were then applied and the probability of having JIIM was determined for each case. The sensitivity and specificity of the EULAR/ACR criteria were compared with those of other existing criteria. RESULTS: The sensitivity/specificity of the EULAR/ACR classification criteria were 92.1/100% with muscle biopsy data (n = 38); 86.7/100% without muscle biopsy data (n = 30) and 89.7/100% in our total cohort (n = 68). The sensitivity of Bohan and Peter's criteria and Tanimoto's criteria were 80.9 and 64.7% in our total cohort, respectively. Among 68 physician-diagnosed JIIM patients, seven cases (three JDM and four overlap myositis) were not classified as JIIM because the probability did not reach the cut-off point (55%). The three JDM patients all presented with only one of the three skin manifestations that are listed in the criteria: Gottron's sign. CONCLUSION: Our validation study with Japanese JIIM cases indicates that the EULAR/ACR classification criteria for IIM generally perform better than existing diagnostic criteria for myositis.

Primaquine plus clindamycin as a promising salvage therapy for Pneumocystis jirovecii pneumonia: A retrospective analysis in Japanese patients.

Treatment of intractable Pneumocystis jirovecii pneumonia (PCP) patients with primaquine (PQ) in combination with clindamycin (CLDM) was conducted by the Research Group on Chemotherapy of Tropical Diseases (RG-CTD), as a kind of compassionate use. Primaquine was not nationally licensed at the time but imported by RG-CTD for the use in a clinical research to investigate safety and efficacy in malaria treatment. Eighteen Japanese adult patients thus treated were analyzed. Prior to the treatment with PQ-CLDM, most of the patients had been treated with trimethoprim-sulfamethoxazole first, all of which being followed by pentamidine and/or atovaquone treatment. This combination regimen of PQ-CLDM was effective in 16 (89%) patients and developed adverse events (AEs) in five (28%) patients. AEs included skin lesions, methemoglobinemia, and hepatic dysfunction, though none of them were serious. As a second-line or salvage treatment for PCP, PQ-CLDM appears to be a better option than pentamidine or atovaquone. Currently in Japan, both PQ and CLDM are licensed drugs but neither of them is approved for treatment of PCP. Considering the potentially fatal nature of PCP, approval of PQ-CLDM for treating this illness should be urged.

Safety and effectiveness of adalimumab in Japanese patients with juvenile idiopathic arthritis: Results from a real-world postmarketing study.

OBJECTIVES: This study was conducted to assess the real-world safety and effectiveness of adalimumab in patients with juvenile idiopathic arthritis (JIA). METHODS: In this all-case, postmarketing surveillance study (NCT01412021) conducted in Japan, patients receiving adalimumab for JIA affecting multiple joints were observed for 24 weeks. The safety (adverse drug reactions [ADRs]/serious ADRs) and effectiveness (4-variable Disease Activity Score in 28 joints using erythrocyte sedimentation rate [DAS28-4/ESR] remission rate) were assessed. RESULTS: In the safety population (n = 356), 90.3% (65/72; weight, ≥15-<30 kg) of patients received adalimumab 20 mg every 2 weeks (q2w) and 98.3% (236/240; weight ≥30 kg) received 40 mg q2w. Incidence of ADRs and serious ADRs was 29.8% (106/356) and 3.4% (12/356), respectively. Incidence of ADRs was significantly higher in patients aged <15 years vs. ≥15 years (34.6% vs. 21.1%, p = .0072), those with comorbidities vs. without (38.3% vs. 25.7%, p = .0155), and those receiving dose <40 mg q2w vs. ≥40 mg q2w (38.8% vs. 26.9%, p = .0418). DAS28-4/ESR remission rate improved from 21.7% (36/166) at baseline to 74.7% (112/150) at week 24. CONCLUSIONS: Adalimumab was well tolerated and had acceptable safety and effectiveness in patients with JIA in the real-world setting.

Clinical practice guidance for Sjögren's syndrome in pediatric patients (2018) - summarized and updated.

There are a considerable number of pediatric patients with Sjögren's syndrome (SS); however, SS is generally considered rare among children. Pediatric patients with SS report fewer sicca symptoms; therefore, many are under-diagnosed and cannot access appropriate medical management. Therefore, we propose a newly developed guidance for the diagnosis, treatment, and management of pediatric SS, including epidemiology, clinical features, and diagnostic examination methodology. The aim of this guidance was to standardize the medical care of pediatric SS in Japan, and we published the Japanese version by YODOSHA in 2018. This article is the English version, which is summarized and updated. This guidance will need to be revised in the near future as additional clinical data become available.

Clinical characteristics and treatment of 50 cases of Blau syndrome in Japan confirmed by genetic analysis of the NOD2 mutation.

OBJECTIVES: To collect clinical information and NOD2 mutation data on patients with Blau syndrome and to evaluate their prognosis. METHODS: Fifty patients with NOD2 mutations were analysed. The activity of each NOD2 mutant was evaluated in HEK293 cells by reporter assay. Clinical information was collected from medical records through the attending physicians. RESULTS: The study population comprised 26 males and 24 females aged 0-61 years. Thirty-two cases were sporadic, and 18 were familial from 9 unrelated families. Fifteen different mutations in NOD2 were identified, including 2 novel mutations (p.W490S and D512V); all showed spontaneous nuclear factor kappa B activation, and the most common mutation was p.R334W. Twenty-six patients had fever at relatively early timepoints in the disease course. Forty-three of 47 patients had a skin rash. The onset of disease in 9 patients was recognised after BCG vaccination. Forty-five of 49 patients had joint lesions. Thirty-eight of 50 patients had ocular symptoms, 7 of which resulted in blindness. After the diagnosis of Blau syndrome, 26 patients were treated with biologics; all were antitumour necrosis factor agents. Only 3 patients were treated with biologics alone; the others received a biologic in combination with methotrexate and/or prednisolone. None of the patients who became blind received biologic treatment. CONCLUSIONS: In patients with Blau syndrome, severe joint contractures and blindness may occur if diagnosis and appropriate treatment are delayed. Early treatment with a biologic agent may improve the prognosis.

Clinical practice guidance for juvenile dermatomyositis (JDM) 2018-Update.

Juvenile dermatomyositis is the most common type of juvenile idiopathic inflammatory myopathy mainly affecting the skin and proximal muscles. We have published the Japanese version of 'Clinical practice guidance for juvenile dermatomyositis (JDM) 2018 'consisting of a review of articles in the field and evidence-informed consensus-based experts' opinion on the treatment strategy in collaboration with The Pediatric Rheumatology Association of Japan and The Japan College of Rheumatology under the financial support by 'Research on rare and intractable diseases, Health and Labor Sciences Research Grants'. This article is a digest version of the Japanese guidance.

Identification of autoantibodies using human proteome microarrays in patients with IPEX syndrome.

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is one of the inborn errors of immunity, characterized by impaired function of the regulatory T cells. Clinical manifestations of IPEX syndrome are characterized by various autoimmune diseases with autoantibodies. The comprehensive analysis for autoantibodies using human proteome microarrays in the four patients with IPEX syndrome was performed. The numbers of the highly expressed autoantibody showing relative log2 ratios greater than 1 were 1876, 513, 234 and 831 (mean: 864), respectively. Some novel autoantibodies which could explain the phenotypes of patients, adrenal dysfunction, muscular hypotonia, afibrinogenemia, enteropathy and pancytopenia were identified. Various kinds of autoantibodies targeting testis-specific antigens were also identified. Human proteome microarray is a powerful tool to understand the pathophysiology of IPEX syndrome. The larger cohort analysis using this method will provide further understanding of the impaired immune tolerance in humans.

Regulatory T-cell dysfunction induces autoantibodies to bullous pemphigoid antigens in mice and human subjects.

BACKGROUND: Regulatory T (Treg) cells play a crucial role in peripheral immune tolerance in multiple organs, including the skin. Thus far, the effect of peripheral immune tolerance failure on autoantibody-related autoimmune reactions to the skin is unclear. OBJECTIVE: We sought to elucidate the target autoantigens in the skin under the condition of Treg cell dysfunction caused by forkhead box P3 (Foxp3) gene mutations in scurfy mice and patients with immunodysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome. METHODS: Sera and skin from scurfy mice and sera from patients with IPEX syndrome were analyzed to detect target autoantigens by using immunofluorescence studies, ELISAs, and immunoblotting. The pathogenicity of scurfy IgG was examined by using a passive transfer experiment. CD4+ T cells from scurfy mice were transferred to immunodeficient mice to examine their pathogenicity. Signal transducer and activator of transcription 6 (Stat6)-/- scurfy mice were analyzed to further clarify the molecular pathway of autoantibody production. Follicular helper T-cell counts are measured in Stat6-/- scurfy mice and scurfy mice. RESULTS: Scurfy mice spontaneously generated IgG autoantibodies to the dermal-epidermal junction, which had been class-switched from IgM within 12 days after birth. The target autoantigens were murine BP230 and type XVII collagen (COL17). The scurfy polyclonal autoantibodies did not induce skin fragility in neonatal mice. Autoantibody production was induced by CD4+ T cells from scurfy mice and was ameliorated by Stat6 gene knockout in association with a decrease of follicular helper T cells. We also identified autoantibodies to COL17 and BP230 in patients with IPEX syndrome and found an association between production of autoantibodies to COL17 and an eczematous skin phenotype. CONCLUSIONS: Dysregulation of Treg cells generates autoantibodies to COL17 and BP230 in vivo.

Long-term follow-up of IPEX syndrome patients after different therapeutic strategies: An international multicenter retrospective study.

BACKGROUND: Immunodysregulation polyendocrinopathy enteropathy x-linked (IPEX) syndrome is a monogenic autoimmune disease caused by FOXP3 mutations. Because it is a rare disease, the natural history and response to treatments, including allogeneic hematopoietic stem cell transplantation (HSCT) and immunosuppression (IS), have not been thoroughly examined. OBJECTIVE: This analysis sought to evaluate disease onset, progression, and long-term outcome of the 2 main treatments in long-term IPEX survivors. METHODS: Clinical histories of 96 patients with a genetically proven IPEX syndrome were collected from 38 institutions worldwide and retrospectively analyzed. To investigate possible factors suitable to predict the outcome, an organ involvement (OI) scoring system was developed. RESULTS: We confirm neonatal onset with enteropathy, type 1 diabetes, and eczema. In addition, we found less common manifestations in delayed onset patients or during disease evolution. There is no correlation between the site of mutation and the disease course or outcome, and the same genotype can present with variable phenotypes. HSCT patients (n = 58) had a median follow-up of 2.7 years (range, 1 week-15 years). Patients receiving chronic IS (n = 34) had a median follow-up of 4 years (range, 2 months-25 years). The overall survival after HSCT was 73.2% (95% CI, 59.4-83.0) and after IS was 65.1% (95% CI, 62.8-95.8). The pretreatment OI score was the only significant predictor of overall survival after transplant (P = .035) but not under IS. CONCLUSIONS: Patients receiving chronic IS were hampered by disease recurrence or complications, impacting long-term disease-free survival. When performed in patients with a low OI score, HSCT resulted in disease resolution with better quality of life, independent of age, donor source, or conditioning regimen.

Evaluation of systemic activity of pediatric primary Sjögren's syndrome by EULAR Sjögren's syndrome disease activity index (ESSDAI).

OBJECTIVES: The purpose of this study is to evaluate systemic disease activity of pediatric Sjögren's syndrome (SS) using European League Against Rheumatism (EULAR) Sjögren's syndrome disease activity index (ESSDAI). METHODS: We retrospectively reviewed medical records of patients with SS who have been diagnosed according to 1999 Japanese diagnostic criteria for SS before 16 years old at KKR Sapporo Medical Center, Hokkaido University Hospital, and affiliated hospitals. We analyzed clinical and laboratory data and calculated ESSDAI at both diagnosis and peak activity. RESULTS: Twenty-five patients (2 boys and 23 girls) were enrolled. Only 4 patients had sicca symptoms at diagnosis. Mean ESSDAI scores at diagnosis and peak activity were 12.68 (2-31) and 15.08 (2-38), respectively. Only 3 patients were inactive (ESSDAI score <5) at diagnosis. Frequently involved domains at diagnosis were the biological (96%) followed by the constitutional (68%), glandular (44%), articular (44%), cutaneous domains (28%), renal (16%), and central nervous system (12%). At peak activity, biological domain (96%) was followed by the constitutional (72%), glandular (60%), articular (44%), cutaneous (28%), central nervous system (20%), and renal domains (16%). CONCLUSION: Pediatric SS is suspected from active systemic manifestations. The items of ESSDAI are useful clues to the diagnosis of pediatric SS.

Myositis-specific autoantibodies in Japanese patients with juvenile idiopathic inflammatory myopathies.

OBJECTIVES: The aim of our study is to clarify the association of myositis-specific autoantibodies (MSAs) with clinical and laboratory features in Japanese patients with juvenile idiopathic inflammatory myopathies (JIIMs). METHODS: We retrospectively analyzed the frequency of MSAs and their association with clinical or laboratory findings in 25 Japanese patients with JIIMs in Hokkaido district. RESULTS: Eighteen of the 25 patients (72%) were positive for MSAs; seven with anti-melanoma differentiation associated gene (MDA) 5 (28%), five with anti-transcriptional intermediary factor (TIF)-1γ (20%), four with anti-MJ/nuclear matrix protein (NXP)-2 (16%), two with anti-Jo-1 (8%), one with anti- HMG-CoA reductase, one with anti-signal recognition peptide (SRP) antibodies (4% each), including co-existence and transition of MSAs in one patient each. Anti-MDA5 antibodies were related to interstitial lung disease (ILD) and arthritis but not to amyopathic juvenile dermatomyositis. Drug-free remission was achieved, once ILD was overcome in this group. Anti-TIF-1γ antibodies were associated with typical rashes and mild myositis. Anti-MJ/NXP2 and anti-SRP antibodies were associated with severe muscle weakness. No patient was complicated with malignancy. CONCLUSION: Anti-MDA5 antibodies are prevalent and closely associated with ILD in our series compared with other countries. There was no apparent difference in clinical features associated with other MSAs among races.

Progression of palindromic rheumatism to juvenile idiopathic arthritis in a Japanese girl carrying heterozygous L110P-E148Q substitutions of MEFV gene.

Palindromic rheumatism (PR), a rare disease in children, is characterized by recurrent arthritis or periarthritis and asymptomatic interval. We report evolution of PR to juvenile idiopathic arthritis in a Japanese girl with heterozygous complex L110P-E148Q allele of MEFV gene. Poor response to colchicine alone suggests that the MEFV substitution could increase the susceptibility to arthritis rather than caused arthritis associated with atypical Familial Mediterranean Fever. Weekly methotrexate is a choice for such cases.

Difficulty in the diagnosis of bone and joint pain associated with pediatric acute leukemia; comparison with juvenile idiopathic arthritis.

OBJECTIVES: Acute leukemia often causes osteoarthralgia. The aim of this study is characterization of leukemia-associated osteoarthralgia in comparison with juvenile idiopathic arthritis (JIA). METHODS: We retrospectively reviewed clinical records of 31 patients with acute leukemia and 13 patients with articular JIA diagnosed between January 2008 and March 2013. Clinical and laboratory findings at the initial examination were compared among the three groups; 10 leukemia with and 21 leukemia without osteoarthralgia and 13 JIA groups. RESULTS: Eleven of the 31 leukemic patients (35%) had osteoarthralgia before the diagnosis of leukemia. Peripheral leukemic cells were initially absent in 10 of the 31 leukemia patients including three with osteoarthralgia. Platelet counts over 300 × 109/L were common in JIA, but not in osteoarthralgia group. Mean serum lactate dehydrogenase levels were higher in both of the leukemia groups than JIA group but often within normal or near-normal levels in the leukemia groups. Magnetic resonance imaging was examined in three leukemic patients and demonstrated osteomyelitis-like bone marrow edema in two and periarticular infiltration similar to synovitis in one patient. Three leukemic patients with osteoarthralgia showed partial and transient responses to antibiotic therapy. CONCLUSIONS: Leukemia-associated osteoarthralgia is often indistinguishable from rheumatic diseases by imaging and laboratory findings and should be confirmed by bone marrow examination.

A heterozygous dominant-negative mutation in the coiled-coil domain of STAT1 is the cause of autosomal-dominant Mendelian susceptibility to mycobacterial diseases.

Heterozygous dominant-negative mutations of STAT1 are responsible for autosomal-dominant Mendelian susceptibility to mycobacterial diseases (AD-MSMD). So far, only 7 mutations have been previously described and are localized to 3 domains: the DNA-binding domain, the SH2 domain, and the tail segment. In this study, we demonstrated the first coiled-coil domain (CCD) mutation of c.749G>C, p.G250A (G250A) in STAT1 as a genetic cause of AD-MSMD in a patient with mycobacterial multiple osteomyelitis. This de novo heterozygous mutation was shown to have a dominant-negative effect on the gamma-activated sequence (GAS) transcriptional activity following IFN-γ stimulation, which could be attributable to the abolished phosphorylation of STAT1 from the wild-type (WT) allele. The three-dimensional structure of STAT1 revealed the G250 residue was located distant from a cluster of residues affected by gain-of-function mutations responsible for chronic mucocutaneous candidiasis.