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.