CIRCULATING REGULATIONAL T-CELLS CD4+CD25+HIGHFOXP3+ INKIDNEY TRANSPLANT RECIPIENTS (PRELIMINARY REPORT)

AIM OF THE STUDY. Regulatory T-cells (RTC) are one of mechanisms of immune tolerance development and support. The aim of this research was evaluation of the content of circulating RTC expressing markers CD4, CD25 and Foxp3 in patients with functioning kidney transplant (KT). PATIENTS AND METHODS. 30 stable KT recipients with duration of post-transplant care from 6 to 24 month (averagely 353 days (95%CI 246-459), 7 patients within 1-3 month after KT and 5 healthy persons were enrolled the observational study. All patients received anti-CD25 monoclonal antibodies induction (anti-CD25МАb – basiliximab). Research of CD4, CD25 and FoxP3 lymphocyte expression in peripheral blood was provided by flow cytrometry method. RESULTS. The proportion of CD4+CD25+high FoxP3+ cells from total CD4+ cells number varied widely and was significantly lower than in healthy persons. The total expression of FoxP3 in lymphocytes had highly significant positive correlation with CD4+FoxP3+ cells content. The correlation between absolute number of T-cells with marker FoxP3 and RTC with CD4+CD25 + high FOXP3+ phenotype was revealed (rpearson=0,86; p<0,001). Averagely percentage of RTC from absolute number of FoxP3 expressing cells was 55% (95%CI 43-68). Also positive correlation was revealed between common expression of FoxP3 in CD4+ lymphocytes and RTC with CD4+CD25 +high FOXP3+ phenotype (rpearson=0,95; p<0,001). No correlation was found between СD4+СD25+ cells and RTC(rpearson=-0,08; p=0,68). Ratio or RTC and all cells expressing FoxP3 had distinct tendency to growth with increase of post-transplant period (rpearson=0,42; p=0,024). In patients surveyed within 1-3 months after transplantation and basiliximab content of CD25 on lymphocytes and number of cells with triple mark (СD4+СD25+ high FoxP3+) was very low, approaching to zero. At the same time, expression of CD4 and FoxP3 was high enough in these patients, significantly without differing from patients surveyed in later terms after operation. CONCLUSION. Received data indirectly testify that RTC pool after kidney transplantation is mainly defined by lymphocytes ability to express FoxP3. Causes for decreased RTC content in KT recipients, particulary role of anti-CD25МАb, demand follow up studies.

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