Expansion of autoreactive CD4+CD28(null)  T cells is associated with extraarticular disease manifestations, including rheumatoid vasculitis, and it has recently been demonstrated that expansion of these T cells is associated with anticytomegalovirus (anti-CMV) seropositivity. This study was undertaken to investigate a possible link between latent CMV infection and rheumatoid arthritis (RA).
In a retrospective analysis, anti-CMV antibodies and clinical, serologic, and radiologic parameters of joint destruction were examined in 202 RA patients and 272 healthy controls. In addition, frequencies of CD4+CD28(null)  T cells; concentrations of the cytokines monocyte chemotactic protein 1 (MCP-1), interferon-α (IFNα), and IFN-inducible protein 10; and anti-CMV-specific T cell responses were analyzed in RA patients.
Overall, no significant difference in the frequency of anti-CMV seropositivity between RA patients and healthy controls was observed. Among individuals older than age 55 years, however, anti-CMV IgG antibodies were significantly more frequent in RA patients than controls (65.3% and 54.7%, respectively; P = 0.05). Anti-CMV seropositivity in RA patients was associated with an increased frequency of CD4+CD28(null)  T cells and increased serum concentrations of MCP-1. The frequency of anti-CMV-specific CD4+ T cells producing IFNγ was increased in RA patients compared to controls. Most importantly, anti-CMV-seropositive RA patients showed radiographic evidence of more advanced joint destruction and had increased frequencies of joint-related surgical procedures, indicating more severe joint disease.
Our findings indicate that latent CMV infection aggravates the clinical course of RA and is associated with increased frequencies of CD4+CD28(null)  T cells and of CMV-specific IFNγ-secreting CD4+ T cells.