NCAM1 and endometriosis: Taken together, our results suggest that: (1) the impaired NK cell cytotoxicity in untreated endometriosis patients may be due both to an influx of CD56<sup>+bright</sup>/eNK cells and exosome-induced NKG2D receptor downregulation; and (2) elevated numbers of peripheral CD56<sup>+bright</sup> NK cells could be considered as a potential diagnostic marker for endometriosis.