Interleukin-6 receptor blockade selectively reduces IL-21 production by CD4 T cells and IgG4 autoantibodies in rheumatoid arthritis.

Interleukin-6 (IL-6) levels are known to be increased in patients with rheumatoid arthritis (RA). Tocilizumab, a monoclonal antibody to the IL-6 receptor (IL-6R), reduces disease activity in RA, although its mechanisms of action remain unclear. Since IL-6 regulates cytokine production by CD4 T cells during activation, we investigated whether treatment with tocilizumab altered the phenotype and cytokine production by CD4 T cells in patients with rheumatoid arthritis.

Persistent cryoglobulinemic vasculitis following successful treatment of hepatitis C virus.

There is a well established link between type II mixed cryoglobulinemia (MC) and hepatitis C virus (HCV) infection, and HCV is believed to be the cause of cryoprotein formation and tissue deposition. Successful treatment of HCV infection has resulted in resolution of cryoglobulinemia and vasculitis. We describe 4 patients who had persistent MC and vasculitis despite successful eradication of HCV with antiviral therapy.

Regulation of p38 MAP kinase in CD4+ lymphocytes by infliximab therapy in patients with rheumatoid arthritis.

Tumor necrosis factor alpha (TNFalpha) plays a key role in the pathogenesis of rheumatoid arthritis (RA) and most patients treated with anti-TNFalpha agents show significant improvement in both signs and symptoms. While TNFalpha inhibitors rapidly reduce joint inflammation, the mechanisms by which these agents exert their long-term effects remain unclear. The p38 MAP kinase pathway is one of the signaling pathways triggered by TNFalpha and pharmacological inhibitors of this kinase are being developed for use in RA.