CD28^- Cells Are Increased in Early Rheumatoid Arthritis and Are Linked With Cytomegalovirus Status

Objective: CD3⁺CD8⁺CD28^- cells are higher in Rheumatoid Arthritis (RA). The aim of this study was to assess CD3⁺CD8⁺CD28^- cells in patients with early RA and assess the effects of cytomegalovirus (CMV) seropositivity. Method: In this prospective observation study, 50 RA patients were recruited from Cardiff University Hospital of Wales (UHW) rheumatology outpatient, 25 patients with early disease (disease duration 0-6 months) and 25 patients with established disease (>2 years). These were compared with 25 healthy controls. Clinical and serological markers of inflammation were noted, and peripheral blood mononuclear cells were analyzed using flow cytometry. Results: The percentage of the CD8⁺CD28^- T cells was increased in RA patients and was associated with disease duration. The percentage of CD8⁺CD28^- T cells was increased in CMV positive early and established RA grouped and early RA patients in comparison to CMV negative patients (p < 0.05). There is a weak but statistically significant correlation between the percentage of CD3⁺CD8⁺CD28^- cells and CRP in CMV positive RA patients (r = 0.227, p < 0.05). Conclusion: The percentage of CD8⁺CD28^- T cells is higher in RA patients and correlates with disease duration, highlighting a potential role early in the disease process. These cells were also higher in CMV positive early RA patients which may suggest a role of CMV in disease development.