Expressions of natural cytotoxicity receptors and NKG2D on decidual natural killer cells in patients having spontaneous abortions

Objective: To investigate the relation between expressions of NKp46, NKp44, NKp30, and NKG2D receptors on decidual natural killer cells (dNK) and human spontaneous abortion (SA). Design: Case control study. Setting: University hospital. Patient(s): Twenty-one patients with normal chromosome abortuses and 25 healthy early pregnant women. Intervention(S): Detected the cytolytic activity of dNK to K562 target cells; measured the expressions of NCRs and NKG2D on dNK. Main Outcome Measure(s): Cytotoxicity of dNK and expressions of NKp46, p44, p30, and NKG2D receptors on CD56(bright)CD16(-)/CD56(dim)CD16(+) dNK subsets were detected by flow cytometry. The relations between dNK cytotoxicity and the expression of the receptors on two dNK subsets were investigated. Result(S): The patients with SA expressed higher proportion of NKp44 on CD56(bright)CD16(-)dNK and higher proportions of NKp46 and NKp44 on CD56(dim)CD16(+)dNK with statistical significance. The expressions of NKp44 on CD56(bright)CD16(-)dNK and NKp46 on CD56(dim)CD16(+)dNK correlated with dNK cytotoxicity positively (r(2) = 0.677 and r(2) = 0.634, respectively). The expression of NKp46 on CD56(bright)CD16(-)dNK was much higher than that on CD56(dim)CD16(+)dNK. Conclusion(s): Enhanced dNK cytotoxicity due to increased NKp46 and NKp44 expressions may undergo the susceptibility to SA. Both CD56(bright)CD16(-)dNK and CD56(dim)CD16(+) dNK may be involved in lysing of the target cells. (Fertil Steril (R) 2008;90:1931-7. (C)2008 by American Society for Reproductive Medicine.)