Cytokine and chemokine receptor profile of peripheral blood mononuclear cells during treatment with infliximab in patients with active rheumatoid arthritis

Objectives: To analyse immunological changes during treatment with a monoclonal anti-tumour necrosis factor alpha (TNFalpha) antibody, infliximab, in patients with rheumatoid arthritis (RA). Methods: 25 patients with RA and 5 patients with other arthritides were studied during the first 6 weeks of treatment with infliximab. At the start of treatment and after 2 and 6 weeks, spontaneous expression of CCR3 and CCR5 on peripheral blood T cells and monocytes was studied by flow cytometry. The secretion and mRNA expression of interferon gamma (IFNgamma), interleukin (IL) 4, IL5, and TNFalpha from phytohaemagglutinin (PHA) stimulated peripheral blood mononuclear cells was measured with an ELISA and RT-PCR. Plasma levels of C reactive protein, serum amyloid protein A, rheumatoid factor, and antibodies to filaggrin and citrullinated cyclic peptide were measured with an ELISA. Results: The number of CD4 T cells and CD14 monocytes expressing CCR3 ( p = 0.013, p = 0.009, respectively) and CD8 T cells expressing CCR5 ( p = 0.040) as well as PHA stimulated secretion of IL4 and IFNgamma (p< 0.05) increased during treatment in patients with RA. 15 (60%) patients with RA achieved clinical response ( at least ACR20) during the first 2 weeks. The number of T cells expressing CCR3 and CCR5 was higher before treatment in non-responders than in responders ( p< 0.05). The number of T cells increased in responders. Conclusion: Increase in secretion of Th1 and Th2 cytokines together with induced expression of chemokine receptors on T cells and monocytes suggest restoration of peripheral cell mediated immunity and blockade of the accumulation of inflammatory cells in joints as response to treatment.