Regulatory T cells in peripheral blood of patients with mixed connective tissue disease

Abstract

Objective: To determine the percentage and absolute number of CD4⁺ regulatory T‐cells (Treg) in 48 patients with mixed connective tissue disease (MCTD).

Methods: Data were classified on the basis of the stage of the disease: 17 patients were in the active stage and 31 in the inactive stage. The absolute number of CD4⁺/intracellular interleukin‐10⁺ (IL‐10⁺) and CD4⁺CD25^+high Treg cells was determined by flow cytometry. The percentage of CD4⁺CD25^+high suppressor T‐cells was determined on the basis of Foxp3 expression.

Results: The percentage and the absolute number of CD4⁺CD25^+high Treg cells were lower in patients than in healthy controls (p<0.04), and were further decreased in patients with active MCTD and were lower than in the inactive stage (p<0.01). There was an increase in the percentage and absolute number of CD4⁺IL‐10⁺ Treg cells in patients with MCTD compared to the healthy controls (p<0.02). The percentage of CD4⁺IL‐10⁺ Treg cells was higher in the active stage of MCTD than in the inactive stage of the disease (p<0.005). However, we did not find any significant difference in the absolute number of CD4⁺IL‐10⁺ Treg cells between the patients in the active and inactive stages of MCTD.

Conclusion: Our results suggest that the decrease in the number of CD4⁺CD25^+high Treg cells in an important factor in the immunoregulatory disturbance in patients with MCTD. We suggest that the increase in the number of CD4⁺IL‐10⁺ Treg cells is a compensatory mechanism aiming to restore the balance between type 1 and type 2 cytokines in MCTD.