Background Previous studies have shown that local immune cells in the feto-maternal interface are recruited from peripheral blood, and that chemokines and their receptors play an initial and key role in this recruitment process. In this study, we aimed to determine whether spontaneous abortion is associated with the expression of chemokine receptors CCR3, CCR5, and CXCR3 on CD4^＋ T cells. Methods Peripheral blood, spleen, and thymus were collected from the spontaneous abortion mouse model CBA/JxDBA/2 （SA group, n=14）, the normal pregnant mouse model CBA/JxBALB/c （NP group, n=13）, and normal non-pregnant CBA/J mice （NNP group, n=11）. The number of chemokine receptors CCR3, CCR5, and CXCR3 expressed on CD4^＋ T cells was measured by double-label flow cytometry （FCM） method. Results In peripheral blood, the SA group had significantly lower CCR3 expression （P 〈0.01） and higher CCR5 and CXCR3 expression （P 〈0.01） on CD4^＋ T cells than did the NP group. But comparing these chemokines between the SA and NNP groups, there was no significant difference （P 〉0.05）. In spleen, the SA group expressed significantly lower CCR3 expression （P 〈0.01） and higher CCR5 and CXCR3 expression （P 〈0.05） on CD4^＋ T cells than did the NP group. When compared with the NNP group, the SA group had significantly higher CCR3 expression （P 〈0.01）, but was not statistically different with regards to the other two chemokines （P 〉0.05）. In thymus, the SA group had significantly lower CCR3 expression （P 〈0.05） and higher CXCR3 expression （P 〈0.05） on CD4^＋ T cells than the NP group, with no significant difference in CCR5 expression （P 〉0.05）. Compared with the NNP group, the SA group had higher CCR3 expression （P 〈0.01）, but there was no statistical difference in CXCR3 and CCR5 expression （P 〉0.05） between the two groups. Conclusion The abnormal expression of CCR3, CCR5 and CXCR3 on CD4^＋ T cells may play an important role in the pathogenesis of sponta
Background Chemokines and their receptors have been a research focus in transplantation immunology. Chemokines and their receptors play a role in lymphocyte recruitment and differentiation process. This study aimed to observe whether IL-4 and IL-10 may regulate the expression of chemokine receptors CCR3, CCR5 and CXCR3 on CD4^＋ T cells in CBA/J×DBA/2 mouse model and to explore the role of CCR3, CCR5, CXCR3 in immune tolerance in pregnancy. Methods The mouse model of spontaneous abortion （CBA/J×DBA/2） and the normal pregnant mouse model （CBA/J×BALB/c） were used. CBA/J×DBA/2 mice were injected with IL-4 （CBA/J×DBA/2-IL-4）, IL-4 and IL-10 （CBA/J×DBA/2-IL-4＋IL-10）, or normal saline （CBA/J×DBA/2-NS） as a control. The expression of CCR3, CCR5 and CXCR3 on CD4^＋ T cells from mouse peripheral blood was measured by the double-labelled FCM method, and the embryo resorption rate was also examined. Results The embryo resorption rate in the CBA/J×DBA/2 group without any treatment was significantly higher than that in the CBA/J×BALB/c group （17.9% vs 3.7%, P 〈0.01）. The embryo resorption rate in the CBA/J×DBA/2 group immunized with IL-4 or IL-4 together with IL-10 was significantly decreased, compared with that in the control and NS groups respectively. CCR3 expression on CD4^＋ T cells in the CBA/J×DBA/2 group without any treatment was significantly lower than that in the CBA/J×BALB/c group （0.3738±0.3575 vs 1.2190±0.2772, P 〈0.01）; both CCR5 （3.0900±1.5603 vs 1.2390±0.6361, P〈0.01） and CXCR3 （2.4715±0.9074 vs 0.9200±0.5585, P 〈0.01） expressions on CD4^＋ T cells of the CBA/J×DBA/2 group without any treatment were significantly higher than those of the CBA/J×BALB/c group. Significant up-regulation of CCR3 and down-regulation of CXCR3 were found in the CBA/J×DBA/2 group treated with IL-4 （CCR3： 2.0360±0.6944, CXCR3： 1.3510±0.5263, P〈0.01） or IL-4 and IL-10 （CCR3： 1.8160±1.0947, CXCR3：1.0940±0.7168, P〈0.01）. Because of the CCR5, IL-
