Objective To investigate the effects of allograft inflammatory factor-1 (AIF-1) and (RANTES) in sera and deciduas on unexplained early spontaneous abortion. Methods AIF-1 and RANTES were examined in sera and deciduas/endometria of 43 unexplained early spontaneous abortion women (group A), 40 healthy women with early pregnancy(group B) and 20 healthy women with no pregnancy (group C). Immu- nohistochemistry and enzyme linked immunosorbent assay (ELISA) were used in this study. Results AIF-1 protein was expressed both in deciduas of group A and in endometria of group C. In group A, H scores in the recurrent abortion deciduas specimens were significantly greater than those in the first abortion;in endometrium, expression of AIF-1 was greater in the secretory than in proliferative phase of group C. In group B, concentrations of RANTES in sera were higher in 7th-8th week of pregnancy than in 6th-7th and >8th week of pregnancy; expression of AIF-1 protein showed a negative correlation with RASNTES concentration; a significant increase of the RANTES levels in sera and tissue was observed in group B. Conclusion These results demonstrate, for the first time, that AIF-1 are expressed in deciduas of unexplained spontaneous abortion suggesting that AIF-1 involve in alloimmune abortion; RANTES might act as a novel blocking antibody;AIF-1 and RANTES might act as reliable markers for diagnosis of early alloimmune abortion. Objective To investigate the effects of allograft inflammatory factor-1 (AIF-1) and (RANTES) in sera and deciduas on unexplained early spontaneous abortion. Methods AIF-1 and RANTES were examined in sera and deciduas / endometria of 43 unexplained early spontaneous abortion women (group A), 40 healthy women with early pregnancy (group B) and 20 healthy women with no pregnancy (group C). Immu- nohistochemistry and enzyme linked immunosorbent assay (ELISA) were used in this study. Results AIF-1 protein was expressed both in deciduas of group A and in endometria of group C. In group A, H scores in the recurrent abortion deciduas specimens were significantly greater than those in the first abortion; in endometrium, expression of AIF-1 was greater in the secretory than in proliferative phase of group C. In group B, concentrations of RANTES in sera were higher in 7th-8th week of pregnancy than in 6th-7th and> 8th week of pregnancy; expression of AIF-1 protein showed a negative correlation with R A significant increase of the RANTES levels in sera and tissue was observed in group B. Conclusion These results demonstrate, for the first time, that AIF-1 are expressed in deciduas of unexplained spontaneous abortion suggesting that AIF-1 involve in alloimmune abortion; RANTES might act as a novel blocking antibody; AIF-1 and RANTES might act as reliable markers for diagnosis of early alloimmune abortion.