Systemic-onset juvenile idiopathic arthritis (sJIA) is a severe and steroid-dependent disease of unknown etiology that sometimes progresses to a fatal disease known as the macrophage activation syndrome. The investigation of inflammatory cytokines and receptor levels revealed an increase in interleukin (IL)-6 and soluble IL-6 receptor (sIL-6R) in serum of patients with active sJIA. The clinical symptoms and signs of the disease are presumably attributable to the continuous elevation of IL-6 and sIL-6R levels in serum. The characteristic fever spikes parallel IL-6 levels. In children, a long-term exposure to high levels of IL-6 causes severe growth impairment, as suggested by recently established studies of IL-6 transgenic mice. The biological functions of IL-6 are expressed through the binding of IL-6/IL-6R complex to gp130. The administration of tocilizumab (a recombinant humanized anti-IL-6R monoclonal antibody) exerts its action by preventing the binding of IL-6 to its receptor and, therefore, preventing the activation of gp130. After a few cases of compassionate use of tocilizumab, phase I and II studies of tocilizumab were conducted in children with sJIA, revealing that tocilizumab abruptly reduced the typical symptoms of inflammation and improved laboratory abnormalities. This article describes the experience in Japan regarding the treatment of sJIA with tocilizumab and supports the hypothesis that high levels of IL-6 may play an important role in the pathogenesis and maintenance of this disease. A confirmation of the role of tocilizumab in the treatment of sJIA will be provided by the results of the ongoing phase III study in Japan.

A 10-year-old girl with autoimmune hepatitis (AIH) was reported. She was admitted to our hospital because of cholestasis and elevation of liver enzymes for 2 months. Laboratory examination revealed that EBV-DNA copy number in the PBMNC (peripheral mononuclear cells) was 1.2 x 10(3) copies/microg of DNA, hypergammaglobulinemia, and positive antinuclear antibody, positive anti-smooth muscle antibody. The histology of her liver biopsy specimen revealed interface hepatitis, dense mononuclear cell infiltrates, mild fibrosis, and negative for EBV in situ hybridization assay indicating AIH and not EBV-associated hepatitis. She was treated firstly with methylprednisolone pulses, then will prednisolone p.o.+azathioprine p.o.. Intravenous cyclophosphamide pulse therapy was introduced because of her abnormal immune pathology. All abnormal laboratory parameters improved to normal levels within 2 months, and EBV-DNA copy number in the PBMNC became negative after 4 months. The histology of liver biopsy specimen was useful for the diagnosis of AIH in such a difficult case needed to be differentiated from EBV hepatitis.

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One month after treatment with γ-globulin for Kawasaki disease, an 18-month-old girl developed Evans' syndrome in addition to drug-induced hypersensitivity syndrome (DIHS) after a second γ-globulin treatment. She suffered from hyperbilirubinemia, hemolytic anemia, and thrombocytopenia. The findings and her clinical course involved plasma exchange and treatment with prednisolone, with good results. Peripheral lymphocyte stimulation tests indicated that γ-globulin was the likeliest cause of the DIHS. A real-time polymerase chain reaction test showed the human herpes virus (HHV)-6 genome in peripheral blood. We demonstrated that a primary infection or infection reactivation by the HHV-6 virus was involved in the development of γ-globulin-induced hypersensitivity and Evans' syndrome.

A case of human parvovirus B19 (B19) infection is reported. A 6-year-old previously healthy girl was admitted to our hospital complaining of slight fever and petechial hemorrhage on her neck, trunk and the proximal parts of extremities. On admission, the platelet count was within normal range (180 x 10(3)/microliter) but white blood cells and reticulocytes were moderately suppressed (2.4 x 10(3)/microliter and 1@1000, respectively). The purpura disappeared in a week and the blood cell counts fully recovered without any specific treatment. Detection of B19 DNA and anti-B19 IgM antibody in the serum on admission led to the final diagnosis. Since the cellular receptor for B19, the blood group P antigen, is expressed on vascular endothelial cells as well as erythroid progenitor cells, the purpura was considered to be the result of direct vascular injury. She was very unique as she subsequently exhibited papular-purpuric gloves and socks syndrome and erythema infectiosum during follow-up. This case may provide a new insight into the pathogenesis of cutaneous manifestations of B19 infection.