Changes And Clinical Significance Of Natural Kill Cell In Peripheral Blood Of Patients With Myelodysplastic Syndrome

ObjectiveTo analyze the percentage and functional changes of natural kill (NK) cell in peripheral blood of myelodysplastic syndrome (MDS) patients so as to evaluate the relationships between these changes and hematopoietic functions and explore the role of NK cell in the pathogenesis of MDS.MethodsBy flow cytometry, the percentage of NK cell (CD3-CD56+CD16+) in peripheral blood lymphocytes was detected in20MDS patients,15acute myelogenous leukemics (AML) and15normal controls from March2013to November2013at our hospital. NK cell activation receptors (NKG2D,NKp44), inhibitory receptors (CD158a,CD158b), perforin and granzyme-β of patients and normal controls were also detected. The correlation between these changes and hematopoietic functions, including the percentages of neutrophil granulocyte (ANC%), lymphocyte (Lym%), reticulocyte (RET%) and hemoglobin, thrombocyte in peripheral blood and the hematopoietic function in bone marrow (CD34+%) were evaluated.Results1.The percentage of NK cell (3.87%±0.97%) in MDS patients was significantly lower than that of normal controls (6.08%±1.37%,P<0.05) and higher than that of AML patients (2.58%±0.78%, P＜0.05).2.The expression of NKG2D in MDS patients (52.83%) was significantly lower than that of normal controls (86.36%, P＜0.05) and higher than that of AML patients (42.00%, P<0.05).3.The expression of CD158a in MDS and AML patients (5.46%±2.40%,4.05%±1.89%) were significantly both lower than those of normal controls (7.97%±2.85%,both P＜0.05).4.The expression of perforin in MDS patients (17.83%) was significantly lower than that of normal controls (59.79%, P＜0.05) and higher than that of AML patients (13.06%, P＜0.05). The expressions of granzyme-β in MDS and AML patients (21.54%,30.65%) were significantly both lower than those of normal controls (83.42%,both P＜0.05).5.The percentage of NK cell (4.06±0.56) and the expression of NKG2D and NKp44(53.42±6.85,median2.46%) in MDS patients with low-risk group were higher than those of high-risk group (3.59±1.37,47.29±8.08,2.07%)(all P＜0.05),the expression of CD158a and CD158b (4.98±2.16,median31.48%) were lower than those of high-risk group (5.15±2.88,32.73%);but all P>0.05. 6.The percentage of NK was positively correlated with ANC%(r=0.780, P＜0.05), but negatively with Lym%and the CD34+%in bone marrow (r=-0.543,-0.610, both P<0.05). The expression of CD158a was positively correlated with CD34+%in bone marrow (r=0.612, P<0.05).The expressions of NKp44, CD158a, perforin and granzyme-P of NK cells had no correlation with hematopoiesis (all P>0.05).ConclusionThe lowered percentage and function of NK may cause the immunological dysfunction and lead to underkilling of pathological hematopoietic cells in MDS.