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.