CD4+CD25+FoxР3+ T regulatory cell analysis in autoimmune diseases
Regulatory T-cells CD4+CD25+FoxP3+CD127 <sup>ow</sup> (Т <sub>regs</sub>) belong to the family of CD4+ T-cell subpopulation. T <sub>regs</sub> display the suppressive activity and play a critical role in regulation and maintenance of autotolerance and immune homeostasis. The generation and differentiation of T <sub>regs</sub> controlled by the transcription factor FoxP3, provide their ability of inhibition both of inflammation and autoimmune reactions. Dysfunction ofFoxP3 is associated with the defective T-cell regulation and autoimmune aggression. Patients with systemic lupus erythematosus (SLE), type I diabetes, inflammatory bowel diseases, thyroiditis and other autoimmune diseases demonstrate lower expression of FoxP3 and defective regulation of T <sub>reg </sub>function. Recently, we have shown downregulation of number and inhibited suppressive function of circulating Tregs in patients with remitting relapsing multiple sclerosis (RRMS) and SLE. Number of T <sub>reg</sub> cells dropped during the periods of relapse and elevated in remission. Increasing the duration and severity of disease was followed by the decline of T <sub>reg</sub> cell numbers. The ability of circulating T-cells separated from peripheral blood of patients to inhibit proliferation in vitro was lower in comparison with the same ability of T <sub>regs</sub> of healthy control donors. The circulating T <sub>regs</sub> count in patients with autoimmune diseases may serve as a diagnostic test for estimation of relapse, and/or indicator for therapy.