RÉSUMÉ
<p><b>OBJECTIVE</b>To investigate the relationship between NK cell count/activity and acute graft-versus-host disease (aGVHD) in patients receiving allogeneic hematopoietic stem cell transplantation (allo-HSCT).</p><p><b>METHODS</b>A total of 26 patients who had undergone allo-HSCT from January to July 2015 were enrolled in this study. The NK cell count/activity in the peripheral blood of recipients on day 30 after allo-HSCT were monitored by using 4-color flow cytometry. The incidence of aGVHD in patients was evaluated by clinical manifestation combinating with related pathologic indicators, and the relationship between NK cell count/activity and aGVHD were analyzed.</p><p><b>RESULTS</b>In the aGVHD group and the no-aGVHD group, the NK cell count and activity on days 30 after allo-HSCT were 655±216 cells/µl vs 1169±372 cells/µl(P=0.002) and 7.3±3.6% vs 9.0±3.6% (P=0.008). In the II-IV grade aGVHD group and the 0-I grade aGVHD group, the NK cell count/activity were 617±220 cells/µl vs 1081±399 cells/µl (P=0.001) and 4.2±1.7% vs 8.3±3.5%(P=0.001). As compared with the 0-I grade aGVHD group, patients in the II-IV grade aGVHD group had higher relapse rate (57% vs 5%)(P=0.010) , lower 1-year progression-free survival(PFS) rate (43% vs 84%)(P=0.010).</p><p><b>CONCLUSION</b>NK cell count/activity on day 30 after allo-HSCT were closely relates with aGVHD, which may be a potential marker for aGVHD and can provide a new target for aGVHD therapy.</p>