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.