Natural Killer Cells in Peripheral Blood and Pregnancy Outcome in Women with Miscarriage

OBJECTIVE- To compare the levels of Natural killer cells in women with history of miscarriage/implantation failure with controls and to observe its association with pregnancy outcome. METHODS- For Peripheral blood Natural Killer Cell analysis three colour immunofluorescence of Lymphocyte markers was performed in 1millilitres of peripheral venous whole blood collected in heparinised and EDTA tubes. The results were calculated as numbers and percentage of total circulating lymphocytes, expressed as a percentage of positive events in relation to all the events acquired by the gating. (NK cell %CD16, 56=5.47-36.60; Absolute CD16+56 = 116.0-612.0/L). RESULTS- Mean age of pregnant cases was 275.2 and of pregnant controls was 265.22. Mean age of nonpregnant cases was 30.15.59 and non pregnant control was 28.37.7. Absolute number and percentage of NK cells were elevated in cases with history of miscarriage. The mean NK cell percentage in pregnant women with history of miscarriage was 18.6611.99 whereas of pregnant control group percentage was 6.58 %3.72. The difference was statistically significant (P value =0.004). Mean NK cell percentage in non-pregnant patient with history of miscarriage was 17.110.49 %. while of non pregnant control was 7.434.67. The difference between the two group was statistically significant (P=0.01) CONCLUSION Miscarriage is a heterogeneous condition. Elevation of natural killer cells has an negative effect on reproductive performance, and NK cells levels in blood are currently being used as a diagnostic test to guide the initiation of therapies in patients with history of miscarriage.