Suppression of natural killer cell activity and interleukin-2 concentration of serum obtained from in vitro fertilization-embryo transfer patients.
PROBLEM: The effect of serum obtained from in vitro fertilization-embryo transfer (IVF-ET) patients on healthy volunteers' natural killer (NK) cell activity was evaluated. We also measured interleukin (IL-2) concentration with IVF-ET patients' serum and clarified the relationship between IL-2 levels and the suppressive effect on NK cell activity. METHOD OF STUDY: A retrospective nonrandomized clinical study was performed. The suppressive effect on NK cell activity and IL-2 concentrations was measured with serum obtained from 30 pregnant and 30 nonpregnant women during an IVF-ET procedure. The suppressive effect of the serum on NK cell activity was evaluated by the formula that we defined in our previous study. RESULTS: The suppression of NK cell activity was significantly higher in the nonpregnant women than in the pregnant women (P < 0.05); however, IL-2 concentration did not differ. There was a positive correlation between the suppression of NK cell activity and IL-2 levels in the pregnant women, but no significant correlation in the nonpregnant women. CONCLUSIONS: These results suggest that the suppression of NK cell activity may be one of the prognostic factors for IVF-ET. In addition, we speculate that an unidentified humoral factor other than IL-2, which could increase NK cell activity, might exist in the serum of the nonpregnant patient.