The Detection And Significance Of Plasma Platelet Auto-antibodies In Patients With Pregnancy Associated Thrombocytopenia

Objective:To evaluate plasma levels of platelet auto-antibodies in patients with pregnancy associated thrombocytopenia and to assess the clinical significance.Methods:A total of 54 women with pregnancy associated thrombocytopenia,44normal pregnant women and 28 women with immune thrombocytopenia(ITP),as well as31 healthy women from the First Affiliated Hospital of Soochow University from March2015 to September 2016 were enrolled in this study.The plasma levels of platelet auto-antibodies against 5 platelet glycoproteins(GPⅨ,GPⅠb,GPⅢa,GPⅡb and P-selectin)were detected by flow cytometric immuno-beads array.Meanwhile,a total of28 pregnant women were selected to detect the levels of platelet auto-antibodies against 5glycoproteins after delivery two days.The difference of platelet auto-antibodies levels were analyzed statistically,and the receiver operating curve(ROC)was constructed to assess the diagnostic value.Results:Compared with normal pregnant women and healthy controls,the plasma levels of auto-antibodies against glycoprotein GPⅨand GPⅠb were significantly increased in patients with pregnancy associated thrombocytopenia(P<0.05),while the levels of other 3 auto-antibodies did not significantly change(P>0.05).Subgroup analysis showed that auto-antibody anti-GPⅠb increased significantly in group with platelet count<20×10~9/L,the positive rates of auto-antibodies anti-GPⅨand anti-GPⅡb in patients with pregnancy associated thrombocytopenia were significantly higher than that in healthy controls respectively,and the total positive rate of auto-antibodies was 59.3%,higher than that in normal pregnant women(31.8%).In addition,the positive rate of the five individual auto-antibodies in patients with pregnancy associated thrombocytopenia was significantly lower than that in ITP patients.The correlation analysis showed that the platelet count was negatively correlated with plasma level of auto-antibody anti-GPⅠb(r=-0.269,P<0.05).However,there was no significant difference between prenatal and postnatal in plasma platelet auto-antibodies(P>0.05).ROC curve analysis showed that the auto-antibody anti-GPⅨcould distinguish pregnancy associated thrombocytopenia from normal pregnancy and healthy controls,the area under the curve(AUC)values were 0.779and 0.893 respectively(P<0.001),the sensitivity was 76.3%and 72.9%,the specificity was69.2%and 100%,and the cutoff values were>0.758 and>0.795,respectively.Moreover,the total effective rate in patients with pregnancy associated thrombocytopenia was 30.95%(13/42)after treated with steroids.There was no significant difference between the therapeutic response and the five platelet autoantibodies.The effective rate of antibody positive group was higher than that of the antibody negative group(9/22 vs 4/20),40.91%and 20.00%respectively,although the difference was not significant(P=0.143).In addition,the total adverse outcome rate was not significantly different from that in the normal pregnancy group(18/47vs9/43)(P=0.073).Conclusion:The plasma expression profile of platelet auto-antibodies in patients with thrombocytopenia in pregnancy was different from ITP patients.The platelet auto-antibodies may not be the main cause of pregnancy associated thrombocytopenia.The plasma levels of auto-antibodyies against platelet membrane glycoproteins GPⅠb/Ⅸcompound were significantly increased,suggesting that these auto-antibodyies may be involved in the pathogenesis of some patients with pregnancy associated thrombocytopenia.The effective rate of antibody positive group in patients with pregnancy associated thrombocytopenia was higher than that of the antibody negative group,suggesting that the detection of the platelet auto-antibodies may have significance in guiding whether patients with pregnancy associated thrombocytopenia need to be treated by steroids.