Fraction of the peripheral blood concentration of CD56+/CD16−/CD3− cells in total natural killer cells as an indication of fertility and infertility☆

Abstract Objective To determine whether the peripheral blood concentration of CD56 + /CD16 − /CD3 − cells, the main natural killer (NK) subpopulation that colonizes the endometrium in the middle and late secretory phase, can be related to fertility or infertility status. Design A case control study. Setting Immunopathology department of an infertility laboratory. Patient(s) A total 99 women were selected (group I: consecutive spontaneous aborters, n=25; group II: sporadic spontaneous aborters, n=30; group III: infertile, n=33; group IV: controls, n=11). Intervention(s) Immunophenotyping of women grouped according to their fertility status. Main outcome measure(s) Peripheral blood lymphocytes were examined by two- and three-color flow cytometry. Result(s) A statistically significant association between endometrial-type peripheral blood (PB) NK cell concentrations and fertility status (groups I and IV vs. groups II and III) was documented. The % /TOTAL PB CD56+CD16−CD3− NK cells was significantly higher [1] in fertile (groups I and IV) than in sporadic aborters/infertile (groups II and III) women, [2] in group I when compared with groups II and III, and [3] in group IV when compared with groups II and III. Conclusion(s) This study indicates that diminished numbers of the % /TOTAL PB CD56+CD16−CD3− NK cells are related to sporadic aborters and infertile women. Thus, the fraction could be used as an indicator of subsequent successful implantation and maintenance of gestation.