High circulating CD3+CD56+CD16+ natural killer-like T cell levels predict a better IVF treatment outcome.

The aim of this study was to determine whether there was any association between peripheral blood NKT-like cells and IVF treatment outcome. In this prospective study, 124 women who underwent IVF treatment for tubal factor were randomly selected in June and July 2011. Blood samples were obtained on the day of vaginal oocyte retrieval prior to the procedure. The percentages of peripheral blood NKT-like cell subsets and the expression levels of mRNA encoding MCP-1 and TNFα in PBMCs were recorded, and their relation to IVF treatment outcomes was analyzed. CD3(+)CD56(+)CD16(+) NKT-like cells were significantly elevated in the pregnant group. The expression level of MCP-1 and TNFα mRNAs in PBMCs from the pregnant group was also increased. Furthermore, both MCP-1 and TNFα mRNA expression were positively correlated with the percentage of CD3(+)CD56(+)CD16(+) NKT-like cells (r=0.55 and r=0.70, respectively). A ROC analysis (AUC=0.634) found that in those women with CD3(+)CD56(+)CD16(+) NKT-like cells >1.85%, the pregnancy rate and live birth rate were higher than in women with cells below this level. An increase in CD3(+)CD56(+)CD16(+) NKT-like cells was associated with a better IVF treatment outcome (OR 4.89, 95% CI=1.86-12.88), with a sensitivity of 47%, specificity of 85%, PPV of 89%, and NPV of 56%. We conclude that an elevated level of circulating CD3(+)CD56(+)CD16(+) NKT-like cells is associated with increased rates of pregnancy and live births in IVF treatment.