Objective. To investigate the safety and efficacy of a recombinant human anti-interleukin-6 (anti-IL-6) receptor monoclonal antibody (MRA) that indirectly inhibits the effects of IL-6 in children with systemiconset juvenile idiopathic arthritis (JIA) refractory to high-dose, long-term corticosteroids.Methods. An individual escalating-dose trial was conducted in 11 children with active systemic-onset JIA who met the inclusion criteria. All were first administered an intravenous dose of 2 mg/kg MRA. Each child without active inflammation was given a second identical dose 2 weeks later and a third identical dose 2 weeks after the second dose. Children with disease flares according to laboratory marker values received a 4-mg/kg dose. Those without disease flares at this dose received a second 4-mg/kg dose 2 weeks later and a third 4-mg/kg dose 2 weeks after the second dose, while those with active inflammation received an additional 3 doses of 8 mg/kg MRA. Efficacy was evaluated every 2 weeks according to responses on the JIA core set of improvement criteria and the results of laboratory tests.Results. MRA abruptly reduced disease activity in 10 of the 11 children, as assessed by the occurrence of febrile episodes, active arthritis, scores on the Childhood Health Assessment Questionnaire, and levels of acute-phase reactants. However, levels of inflammatory reactants fluctuated until the proper MRA dose for each child was reached. Two weeks after the third fixed dose of MRA, 90.9% of all patients had a 30% improvement response, 90.9% had a 50% improvement response, and 63.6% had a 70% improvement response.Conclusion. MRA treatment of children with active systemic disease results in clinical improvement and in normalized levels of acute-phase reactants. MRA was safe and well tolerated and provided greater clinical benefit than conventional corticosteroids, considering the ill effects of IL-6 and adverse events.

To explore the potential applicability of recombinant adeno-associated virus (rAAV) vectors in the treatment of rheumatoid arthritis (RA), primary human fibroblast-like synoviocytes (FLS) derived from patients with RA were infected with rAAV encoding mouse IL-10 under the control of the CMV promoter. Addition of the proteasome inhibitor carbobenzoxy-l-leucyl-l-leucyl-l-leucinal (zLLL) to the cultures dramatically enhanced expression of the IL-10 transgene, in a dose-dependent manner. The increased expression was transient, peaking at 3 days and returning to near baseline by 7 days. The enhancement was observed even when zLLL was added 13 days after infection with rAAV. The effect of zLLL was not specific to either the mIL-10 transgene or the CMV promoter, as similar findings were observed using an rAAV construct encoding alpha1-anti-trypsin under the control of the chick beta-actin promoter or GFP, driven by the CMV promoter. Transgene expression could be repeatedly induced by reexposure to zLLL. Transgene mRNA levels increased in parallel with protein levels. Transgene expression could also be repeatedly induced in vivo by administering zLLL to SCID mice previously injected with rAAV-infected FLS. These data demonstrate that proteasome inhibition can dramatically enhance transgene expression in human RA FLS following infection with rAAV and suggest a possible approach to regulating synovial transgene expression in vivo.

Kawasaki disease (KD) causes coronary artery lesions (CALs) in 500 Japanese children each year. Intravenous gamma-globulin (IVGG) decreases the incidence of these lesions from 25% to 8% of the total KD cases. We examined whether plasma exchange is a safe and effective prophylaxis against CALs in children with KD intractable to IVGG therapy. Eighty-nine children with KD at high risk of CALs were selected on the basis of increases in fractional changes in inflammatory markers such as white blood cell count, neutrophil count, and C-reactive protein between the baseline and 1-2 days after IVGG treatment. Of 105 children who received a second course of IVGG therapy because the initial course was ineffective, plasma exchange (PE) was performed in 46 children who had not responded to the second IVGG treatment. The outcome was compared with the results when a third course of IVGG therapy was given to the other 59 children. No complications occurred with the plasma exchange therapy. CALs developed in only 8 of the 46 children (17.3%) who underwent plasma exchange, but they occurred in 24 of the 59 (40.7%) who had received a third course of IVGG therapy (P << 0.0012). We concluded that PE was a safe, effective prophylactic measure against CALs in children with KD intractable to IVGG therapy. PE should be performed at an early stage, as soon as fractional increases in inflammatory markers are found after IVGG therapy.

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.

We demonstrated that there was a selective insufficiency in the secretion of IFN-gamma in patients with hyper-IgE syndrome. We hope that this fact would offer a new paradigm for understanding this disease.