Five cases of seronegative persistent inflammatory monoarthritis improved with biological therapy.

Persistent inflammatory monoarthritis is defined as inflammation of one joint that continues for longer than 3 months. Most cases remain as nonspecific arthritis after several years. Persistent inflammatory monoarthritis is difficult to diagnose and treat in the early stage because there are no criteria for diagnosis and treatment. We report five seronegative persistent inflammatory monoarthritis cases that affected the left knee, right knee, left knee, left ankle, and right knee. All patients underwent joint punctures; two patients received steroid injections in the affected joint. The bacterial and mycobacterial culture were negative in all patients. Two patients received oral steroids, and two patients were administered nonsteroidal anti-inflammatory drugs; however, their symptoms did not improve, and one patient experienced progression of joint destruction. We investigated the usefulness of biological disease-modifying antirheumatic drugs for the treatment of seronegative persistent inflammatory monoarthritis. We obtained a remarkable improvement effect and prevented the advance of joint destruction.

The effect of anti-IL-6 receptor antibody for the treatment of McH-lpr/lpr-RA1 mice that spontaneously developed destructive arthritis and enthesitis.

BACKGROUND: McH-lpr/lpr-RA1 mice are a new strain of mice which spontaneously develop destructive arthritis and enthesitis in the ankle. There is no published data that drug treatment has been trialed on these mice. This study examined the effect of the mouse anti-IL-6 receptor antibody, MR16-1, for the treatment of arthritis and enthesitis in McH-lpr/lpr-RA1 mice. METHODS: Male McH-lpr/lpr-RA1 mice were randomly divided into control and treatment groups. MR16-1 was administered from 10 weeks of age for the treatment group. Saline was applied for the control group. The drug was administered once a week, at an initial dose of 2 mg, then maintained at 0.5 mg once per week thereafter. The effects were evaluated by the histopathological synovitis score, in vivo imaging using indocyanine green liposomes, and analysis of the gene expression of inflammatory cytokines. RESULTS: Tissue analyses were carried out at 14, 17 and 20 weeks of age. The synovitis scores of treated groups were significantly lower compared with those of the control group at 14 and 17 weeks of age. The kappa coefficient was 0.77. However, progression of entheseal ossification persisted in the MR16-1 treated group. In vivo imaging using indocyanine green liposomes showed significant decreases in signal intensities of treated groups at week 14, but no significant differences were observed at week 18. Blood serum amyloid A levels in treated groups were significantly lower at 17 weeks of age. The gene expression levels of Tnf and Il17 were also significantly lower in MR16-1 treated groups. CONCLUSIONS: Administration of the anti-IL-6 receptor antibody is effective for the treatment of synovitis and bone destruction of McH-lpr/lpr-RA1 mice. McH-lpr/lpr-RA1 mice may be a suitable experimental model for the development of new treatments for destructive arthritis and enthesitis. IL-6 signal blockade could contribute to the treatment of destructive arthritis, and further studies should be carried out to confirm its potential in the prevention of enthesopathy developed to ossification.