Decrease in a specific killer cell immunoglobulin-like receptor on peripheral natural killer cells in women with recurrent spontaneous abortion of unexplained etiology

PROBLEM: The aim of this study was to investigate immunophenotypic characteristics of natural killer (NK) cells by assessing specific molecules expressed in women with recurrent spontaneous abortion (RSA) of unexplained etiology. METHOD OF STUDY: Peripheral blood cells were obtained from 20 RSA women and 15 fertile controls. The expression of perforin, CD94, CD161, CD158a, CD158b, and CD244 on CD3- CD56+ NK cells was analyzed by flow cytometry. RESULTS: A significant decrease in CD158a expression was demonstrated in RSA women (mean +/- SD, 22.9 +/- 8.7%) as compared with that in controls (33.6 +/- 15.7%) (P < 0.05). The percentage of NK cells showing dual expression of CD94 and CD161 was relatively higher in RSA women (55.1 +/- 10.2%) than in the controls (47.1 +/- 19.0%), but without statistically significant (P = 0.096). The expression of perforin, CD158b, or CD244 in RSA women did not differ from that in the controls. CONCLUSIONS: A divergence of the specific NK cell repertoire might be related to the etiology of RSA.