(Objective) Because of the number of pediatric case with rheumatic disease are very rare, that can be experienced in one institution is limited. We think that it is necessary to conduct registry research for the diagnosis, treatment and research in the future under the initiative of the Pediatric Rheumatology Association of Japan. (Methods)This study is a retrospective observational study. Target diseases are juvenile idiopathic arthritis, systemic lupus erythematosus, juvenile dermatomyositis, Sjogren’s syndrome, mixed connective tissue disease, systemic scleroderma, etc. The database （PRICURE ver. 2） is built by FileMaker Cloud on Amazon Web Services server and can be accessed with a common Web browser via an SSL connection. (Results)There are 128 cases has been registered from 13 facilities at the end of February, 2020. (Conclusion)Because there are still few participating facilities, the number of registered cases is also small. In order to contribute to the diagnosis, treatment and research in the future, it is necessary to much more increase registries for pediatric rheumatic patients.

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(Background)The Childhood Myositis Assessment Scale（CMAS） is a muscle strength assessment index for pediatric idiopathic inflammatory myopathy focused on physical functions and endurances widely applied in European and American Pediatric Rheumatology. CMAS can assess muscle strength changes during the process of muscle strength recovery after successful treatment, including in the acute phase. So far, it is not well known to Japanese medical practitioners. The lack of a Japanese version of CMAS is one of the factors that led to the insufficient recognition of CMAS. (PurposeTo translate the CMAS, a muscle strength index for idiopathic inflammatory myopathy in children, into Japanese and validate it. (Methods)The translation was performed by the study team. First, five medical practitioners who didn’t know CMAS examined healthy subjects with the translated version, and the validity of the examinee’s movements was assessed. Second, the examiners assessed movements of each maneuver with different score presented randomly by the examinees. Both assessments were judged by physicians with actual experience scoring CMAS in pediatric rheumatology practices in the United States. (Results)The examinee’s movements and the scores of the movements were correct in most of the assessments. (Conclusion)The Japanese version of the CMAS was judged to be linguistically appropriate and can be used as well as the original version.

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(Background)The lupus low disease activity state（LLDAS）, a novel clinical treatment target, is associated with the suppression of the progression of organ damage in systemic lupus erythematosus（ SLE）. (Methods)This retrospective study evaluated the complete remission and LLDAS in patients with SLE diagnosed in childhood and adolescence using their medical records. (Results)Thirteen patients were included in the analysis. The median age at the onset was 12.4 years（range 8.9–16.1 years）, and the female-to-male ratio was 11：2. The median current age was 24.5 years （range 9.8-35.7 years）. The average duration of the follow-up was 10.3 years （1-23.6 years）. Nine（69％） patients achieved an LLDAS, and four （31％） did not. The average LLDAS achievement period was 770 days（ 140–1,735 days）, and was achieved by 2 people within 6 months and 3 within 18 months. Four of those five patients used steroid pulse therapy and tacrolimus as induction therapy. Four of the nine patients who achieved an LLDAS were in a state of remission on therapy at the final observation. (Conclusion)The immunosuppressant drug selected for the induction of a remission differed depending on the timing of the onset of SLE, and as a result, it may be involved in the glucocorticoid administration and LLDAS achievement periods.

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The prevalence of thrombocytopenia has been reported 7 to 30％ in patients with systemic lupus erythematosus（ SLE） and less than 15％ of patients have thrombocytopenia as a first symptom of SLE. The most common cause of secondary immune thrombocytopenic purpura （ITP） is SLE. Herein, we report 5 cases with childhood-onset SLE （cSLE） diagnosed following by thrombocytopenia. Four of the five cases were girls and the age at disease onset was 5-14 years （median : 11 years of age）. Skin rash on the lower leg was recognized as the first manifestation in 2 cases. Thrombocytopenia was accidentally noticed by examination for other diseases in the other 3 cases. All cases showed refractory thrombocytopenia and referred to our hospital. The platelet count at the first visit of our hospital was as low as 1,000 to 93,000/μL. All patients showed high anti-nuclear antibody titer and met the classification criteria for cSLE. The range of SLE disease activity index score was 7 to 14, which indicated high disease activity. Four cases showed positive for antiphospholipid antibody, and 2 met the diagnostic criteria for antiphospholipid syndrome （APS）. The intravenous glucocorticoid therapy or methylprednisolone pulse therapy was used for all patients, and platelet count and disease activity of SLE were gradually improved. We concluded that patients with refractory ITP should be performed an autoantibody testing for the possibility of SLE and APS.

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【背景】抗Mi-2抗体陽性若年性皮膚筋炎（JDM）は，発症頻度は低いが一般にステロイド薬が有効で 予後がよい炎症性筋炎とされる．今回，我々はステロイド薬抵抗性抗Mi-2抗体陽性JDM 2例を経 験し，大量免疫グロブリン静注療法（IVIG）が有効であったので報告する． 【症例】症例1は，8歳女児で約2か月間にわたり，中等量ステロイド薬を投与したが，十分な筋力の 改善が得られず大量免疫グロブリン療法が有効であった．症例2は，5歳男児．4歳0か月に発症し， ステロイドパルス療法4クールとメトトレキサート，アザチオプリン，シクロホスファミドパルス 療法などの治療を施行したが増悪を繰り返しており，5歳1か月時にIVIGを施行して，寛解維持が 可能となった． 【考察】抗Mi-2抗体陽性JDMは比較的均一な臨床症状を呈し，一般的にステロイド反応性は良好と されているが，今回，明らかにステロイド薬抵抗性と考えられた症例を報告した．このようなス テロイド薬抵抗性抗Mi-2抗体陽性筋炎では，第２選択薬としてIVIGが有用である可能性が示唆され た．

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An 8-year-old girl developed muscle weakness localized in the thighs and upper extremities and had difficulty walking. She had a skin rash, severe muscle weakness, elevated serum creatine kinase levels, and a low score on the Childhood Myositis Assessment Scale. T2-weighted magnetic resonance imaging of the muscles revealed lesions as signal high intensity consistent with myositis. Therefore, the patient was diagnosed with juvenile dermatomyositis（ JDM）. She was treated with two courses of methylprednisolone pulse therapy, with no improvement in symptoms, leading to the diagnosis of JDM-associated macrophage activation syndrome（ MAS）. Accordingly, she showed elevated serum markers of tissue damage and ferritin with a decreased platelet count. The low levels of serum interleukin-6 and interleukin-18 were inconsistent with MAS with systemic juvenile idiopathic arthritis. Eventually, her symptoms alleviated in response to cyclosporine and dexamethasone palmitate without flare. There have only been a few reports of JDM-associated MAS ; hence, its clinical features have not been well-understood. For this patient, we had considered anti-melanoma differentiation-associated gene 5 autoantibody-positive JDM to have resulted in elevations of serum myogenic enzyme and ferritin, which might have caused the delay in the diagnosis of MAS.

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Takayasu arteritis（ TA） and ulcerative colitis（ UC） share many genetic factors, and coexistence of both are not uncommon. We report a case of TA in a 11-year-old girl with UC. She developed total colonic UC at the age of 8. While being treated with azathioprine （AZA） and infliximab （IFX）, pain in the interior thigh during exercise and increased CRP were observed from age 11 years and 2 months old. No exacerbation of UC was found in colonoscopy at that time. Subsequently, pyrexia and malaise developed, and PET-CT showed accumulation in both subclavian arteries, leading to the diagnosis of TA. Methylprednisolone pulse therapy was performed and the dose of AZA was increased as an induction therapy. IFX was continued every 6 weeks. The vascular ultrasound findings worsened as the dose of PSL was tapered and IFX was changed to tocilizumab（ TCZ） at the age of 12 years and 1 months. Thereafter, UC exacerbated and total colectomy was performed at the age of 12 years and 7 months. After the operation, vascular ultrasound findings improved and PSL is being tapered without relapse. TCZ is considered for maintenance therapy in PSL dependent TA patients, but efficacy of TCZ in UC is unclear. Since the overlap of TA and UC is not uncommon, it is necessary to seek the optimum treatment for TA with UC in the future.

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Atlantoaxial rotatory fixation causes neck pain and torticollis in the atlantoaxial joint. Arthritis is rarely the cause of atlantoaxial rotatory fixation, and in cases in which atlantoaxial rotatory fixation is the initial symptom, juvenile idiopathic arthritis （JIA） is seldom considered in the differential diagnosis. However, we report herein two cases of rheumatoid factor （RF） positive polyarticular JIA and enthesitis related arthritis（ ERA） which were both diagnosed during treatment for atlantoaxial rotatory fixation after the patients presented arthritis in other joints. As far as we conducted good research, there were no such case reports other than spondyloarthritis （SpA） which is characterized as enthesitis. Cytokines, such as tumor necrosis factor（ TNF）, IL-17, and IL-23 are thought to play a role in the pathogenesis of SpA. TNF inhibitor, which was previously reported more effective against spondyloarthritis than IL-6 inhibitor, also proved in the present cases characterized as synovitis. TNF inhibitor was previously reported more effective against spondyloarthritis than IL-6 inhibitor. Similarly, TNF inhibitor could be more useful than IL-6 inhibitor not only for enthesitis but also JIA with cervical involvement characterized as synovitis.

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While sarcoidosis is rare in childhood, it should be considered in any differential diagnosis of childhood uveitis. Histological diagnosis of sarcoidosis requires both the pathologic evidence of non-caseating epithelioid granulomas found on tissue biopsy and the exclusion of other diseases. The case was a 14-year-old, Japanese girl. She had dry cough for about 2 weeks and bilateral conjunctival hyperemia for about 5 weeks, and then diagnosed as uveitis. Swelling of lacrimal, parotid and submandibular glands were not observed. Systemic close examinations showed decreased salivary secretion, low pulmonary diffusion capacity. Chest CT examination detected a pulmonary nodule in the left lower lung and patchy consolidations in both basal lungs. Gallium whole body scintigraphy revealed a characteristic pattern of uptakes in the bilateral lacrimal, parotid and submandibular glands, which was called the panda sign, while uptakes in the pulmonary lesions were not evident. Non-caseating epithelioid granulomas were detected on parotid gland biopsy, then she was diagnosed as sarcoidosis histologically. The panda sign on Gallium whole body scintigraphy is a typical and supportive sign for the diagnosis of sarcoidosis and is useful for the selection of an appropriate biopsy site.

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A 14-year-old girl suspected as having Takayasu arteritis（TA） with hypertension found by chance in workplace experience was referred to us. 18Ffluorodeoxy glucose positron emission tomography （18FFDG-PET） revealed FDG uptakes in the aortic arch and bilateral internal carotid artery, even though serological inflammation markers including CRP and ESR were all negative. Oral prednisolone （PSL）（30mg/day） was started, and her clinical symptoms disappeared. One month after starting PSL, FDG uptake on 18FFDG-PET remained significant, even though the patient had no symptoms with negative inflammation markers. After tapering the PSL dosage to 20mg/day, the patient showed exacerbation of disease. The dose of PSL was increased to 25mg/day, and tacrolimus was added. Although the exacerbation had ceased, the patient clinically relapsed again after tapering the PSL dosage to 22.5mg/day. Tocilizumab was added. Subsequently, remission was achieved and maintained with 4mg/day of PSL. Serological inflammation markers are useful for the assessment of disease activity in TA. However, in some patients, inflammation markers remain negative even in active phase, making it difficult to assess disease activity. The 18FFDG-PET is useful for the assessment of disease activity even in such patients with no elevation of inflammatory markers in active phase of TA.

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We report the case of a 4-year-old boy with IgA vasculitis who developed a recurrence of IgA vasculitis 6 months after its first episode. He had a high fever, severe abdominal symptoms, arthralgia, and a marked increase in serum C-reactive protein（CRP） level （up to 22.18mg/dL）. Thus, differentiation from sepsis was needed. Abdominal sonography revealed thickening of the small intestinal wall, enlarged mesenteric lymph nodes, and elevated echogenicity of mesenteric adipose tissue in the lower right abdomen. He was diagnosed as having mesenteric lymphadenitis and panniculitis caused by recurrence of IgA vasculitis, which required prednisolone administration. As sepsis could not be ruled out, an antibacterial drug was administered after blood culture. Palpable purpura was observed in his lower extremities after the clinical features promptly improved. We speculate that the patient’s high fever and elevated serum CRP level resulted from the formation of mesenteric lesions after the breakdown of the gut barrier by IgA vasculitis.

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Anti-dsDNA antibody plays a central role in the pathophysiology of systemic lupus erythematosus （SLE）, while SLE patients negative for anti-dsDNA antibody is rarely present. We investigated the pathophysiology of anti-dsDNA antibody-negative SLE by performing targeted exome analysis. The case was an 11-year-old girl, who had hematuria on urine screening at school. Anti-dsDNA antibody was negative, but she was diagnosed with SLE based on fulfilling 5 of 12 diagnostic criteria for pediatric SLE （malar rash, photosensitivity, urinary cellular cast, positive for antinuclear antibody positive and hypocomplementemia）. At 14 years of age, she developed bilateral toe arthritis with elevation of C1qbinding immune complex. The arthritis was improved by oral administration of prednisolone （PSL） and methotrexate （MTX）, but recurred with a decrease in PSL dose. After changing MTX to mycophenolate mofetil, the arthritis improved, but prurigo and proteinuria developed with reduction of the PSL dosage. Target exome analysis revealed variants in C3 , C7 , MBL2 , CR2 , and CTLA-4 ; all of these genes have been reported to be associated with development of SLE. Considering that anti-dsDNA antibody was negative and C1q-binding immune complex was high, the possible mechanism of SLE in this case was the defect of removing immune complexes, due to C3 , C7 , MBL2 , and CR2 .

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We diagnosed a 2-month-old infant with Kawasaki disease caused by a human parvovirus B19 （HPVB19）infection. On the second day of illness, he presented with respiratory failure and compensated shock. Mechanical ventilation was performed along with a blood transfusion and administration of antibiotics. On the sixth day of illness, 5/6 of the major symptoms of Kawasaki disease resolved, and coronary artery lesions appeared, so intravenous immunoglobulin was administered twice. After that, the symptoms of Kawasaki disease disappeared and he was discharged on the 16th day of illness. Three months later, the coronary artery lesions improved. We considered the possibility of HPVB19 infection due to the findings of erythema of the extremities, anemia, and low-level of complement. Moreover, HPVB19-IgM was positively converted and HPVB19-DNA was detected in the plasma sample. So, it was speculated that HPVB19 was involved in this case of Kawasaki disease. In addition, we examined the cytokine profile to clarify the reason behind such serious symptoms, and discovered that this case involved hypercytokinemia, which is not typical of Kawasaki disease. Therefore, we considered the hyper-cytokine storm caused by the HPVB19 infection as the pathogenesis of this case. Thus, it is necessary to treat Kawasaki disease considering the possibility of HPVB19 infection.

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