Expansion of CD4+CD8+ Double-positive T cells in Rheumatoid Arthritis Patients is Associated with Erosive Disease.

OBJECTIVES CD4+CD8+ double-positive (DP) T cells are expanded in the peripheral blood of a subset of patients with rheumatoid arthritis (RA). This study examines the clinical significance of DP T cells in RA. METHODS In 70 RA patients, DP T cells were measured by flow cytometry. Clinical data were obtained, and hand and feet radiographs were scored according to the Sharp/van der Heijde (SvdH) method. The association between DP T cell frequency and erosive joint destruction was analyzed by correlation and multiple logistic regression analysis. RESULTS Nineteen RA patients (27.1%) displayed increased DP T cell frequencies, which correlated with age (r = 0.288, p= 0.016). Expansion of DP T cells was associated with the occurrence of erosions (94,7% vs 43,1%, p< 0.001), with a higher SvdH joint damage score (24.5 vs 6, p= 0.008) and with more frequent use of biologic or targeted-synthetic DMARDs (68.4% vs 38%, p= 0.02). In patients with non-erosive disease, DP T cell frequencies correlated with the joint space narrowing score (n = 28, r = 0.44, p= 0.02). Logistic regression revealed DP T cells to be associated with erosive disease (OR 1.90, p< 0.05). CONCLUSION Expansion of DP T cells is associated with joint damage and frequent escalation of therapy, possibly suggesting a contribution to more severe RA.