Endometrial CD56+ natural killer cells in women with recurrent miscarriage: a histomorphometric study

Endometrial natural killer (NK) cells were compared in luteal-phase endometrial samples from women with recurrent miscarriage and from normal subjects. Cryostat sections were labelled using a monoclonal antibody to CD56 using an avidin-biotin complex method and a morphometric study performed. Increased mean numbers of CD56+ cells were documented in the endometrium of women with recurrent early miscarriage only. These findings suggest a possible role for NK cells in the pathogenesis of recurrent early pregnancy loss.