CXCR 3 Expression on Cord Blood CD 4^+ T Cells and NK Cells

Th1細胞は造血幹細胞移植後の急性移植片対宿主病(graft-versus-hostdisease:GVHD)の発症に深く関与しているといわれている。今回我々はTh1細胞に発現するとされるキモカインリセプターの1つであるCXCR3を測定し,瞬帯血移植で急性GVHDがなぜ軽度なのかを検討した。臍帯血,成人末梢血と移植後患者末梢血中のリンパ球,NK細胞をモノクローナル抗体(抗CD4,抗CD8,抗CD56,抗HLA-DR,抗CD25)で染色し以下の結果を得た。CD^4+T細胞のCXCR3発現,HLA-DRの発現はいずれも末梢血よりも膀帯血の方が少なかった(p
In order to know why the development of acute graft-ver-sus-host-disease (aGVHD) is significantly milder after stem cell transplantation (SCT) using cord blood, we studied the CXCR3 expression on CD4^+T cells and NK (CD 56^+) cells, based on the fact that CXCR3 is one of the chemokine receptors on Th1 cells. Cord blood (CB) and peripheral blood (PB) from healthy volunTFFrs and patients who received SCT were treated with monoclonal antibodies against CD4, CD25, CD56, CXCR3, and HLA-DR and the antigen expression was analyzed using flow cytometry. The percentage of CXCR3 antigen on GB and PB CD4^+ T cells was 2.6 ± 1.4% and 30.8 ± 3.9%, respectively, demonstrating a significant difference (p < 0.05). However, that on GB and PB NK cells was not significantly different. CXCR3 expression on CB and PB CD4^+T cells stimulated by IL-2 for 72h and 120h was significantly different (p < 0.05), but that on NK cells was not significant. CXCR3 expression on CD4^+ T cells from patients who received allo-CB-SCT and allo-bone marrow transplantation from HLA-mismatched donor was significantly different at one-month post-SCT (p < 0.05). We concluded that the lower CXCR3 expression on GB CD^+T cells and absence of difference in CXCR3 expression on cord blood NK cells facilitated a milder aGVHD.