Changes Of CD4~+CD25~+ Regulatory Cells And Expression Of Foxp3 In Experimental Anti-phospholipid Antibody Syndrome Mice

Objective:To observe the quantitative and functional changes of CD4+CD25+regulatory cells in mice during the development of experimental anti-phospholipid antibody syndrome (EAPS). Methods:To establish the model of EAPS, we immunized BALB/c mice with rhβ2-GP1. Twelve weeks after immunization, aCL,anti-β2GPI titers in the sera, the percentage of the fetal resorptions, activated partial thromboplastin time (aPTT) and platelet counts were assayed. Frequency of CD4+CD25+Treg in peripheral blood mononuclear cells from EAPS mice were determined by flow cytometry, mRNA expression of foxp3 were semi-quantified by RT-PCR. Results:Model mice showed an elevated titers of anti-β2GPI and aCL Abs in the sera (p<0.05), higher resorption percentage (p<0.05), prolonged aPTT (p<0.05), and lower platelet counts (p<0.05). The expressing levels of foxp3 mRNA in the model group was higher than those of control group (p<0.05) in the fourth week after immunization, but the expressing level of Foxp3 mRNA began to decrease in week 8 and were lower than those of control group from week twelve (p<0.05). The frequency of CD4+CD25+Treg cells in model group was similar with that of control group within the eighth week after immunization (p>0.05), but after week twelve, the frequency of CD4+CD25+Treg cells in model group began to get lower than contol group (p<0.05).Conclusion:The decreased number and function of CD4+CD25+Treg cells may contribute to the pathogenic mechanism in EAPS.