The Study Of Relationship Between The Anti-A(B) IgG Subclasses Of Pregnant Women Serum And Hemolytic Disease Of The Newborn

Hemolytic disease of the newborn (HDN) can be seen in incompatible pregnancies. The IgG antibodies in the maternal circulation cross the placenta, cause hemolysis in the fetus. The disease often happens to fetus and the newborn, may lead to abortion. The slight representations are anemia, edema and hepatomegaly; the serious is uterine dead. To the newborn it may cause kernicterus, with the sequela of sport impediment, amentia, etc. This will bring a great pressure to the family and society. Now we have known that there are 26 blood systems and more than 400 blood antigens. Though many blood systems can cause HDN, the most popular are ABO and RhD. In our country, only 0.24% of the Han people is RhD(-),and nearly 5% in the minority, these numbers are lesser than those 15% of the Caucasian, so most of the HDN is caused by ABO system. Most of the ABO incompatible pregnancy can be seen in mother of blood type O, and the fetus is A or B, it can happen in the first labour. The normal clinical test to predict whether it is HDN is Indirect antiglobulin test (IAT). This method can be used to test the weak antibody of the early pregnancy, it has high sensitivity, but the test must be done in the standard condition, and the correlation between titer of alloantibodies and HDN is still deficiency. The objective of this research is to explore relationship between serum anti-A(B) IgG subclasses of pregnant women with ABO blood group incompatibility and HDN, on the basis of knowing the titer of alloantibodies and whether the newborn is HDN. We hope that our results can make up the deficiency of IAT to predict HDN, and bring a more effective method to predict ABO-HDN. We collected 45 paired blood samples of pregnant women with O, RhD(+) , ABO blood group incompatibility and their newborns. They are from the samples of Dalian Red cross blood center, during Oct. 2003 and Oct. 2004. The age of the mothers are between 23 and 30, the weeks of gestation are between 28 and 36 weeks. They are in good health, without innutrition, abnormal pregnancy and other problems. And the samples of the newborn are sent to test within 48 hours after its birth. According to IAT we got the titer of anti-A (B) IgG, and found that 41 of 45 are higher than 64 or equal to 64, the other 4 are lower than 64. And 19 of the 41 are HDN positive, 22 of the 41 are HDN negative; 1 of the 4 is HDN positive, 3 of the 4 are HDN negative. There are 19 women whose titer is higher than 256 or equal to 256, 12 of the 19 are HDN positive, 7 of the 19 are HDN negative. The anti- A or B IgG subclasses were isolated by absorption / elution from the sera of alloimmunized pregnant women. We use IAT to test the titer of the elution, and find that the titer is nearly the same as the titer of the serum. A quantitative enzyme-linked immunosorbent assay (ELISA) was implemented for measuring IgG subclasses. The results for each subclass for a given antibody were expressed as a percentage of the total. In a series of newborns, the mean percentage X ± SD of each subclass was: IgG1 94.64±3.34; IgG2 0.69±0.22; IgG3 4.56±3.31; IgG4 0.12±0.02 in the HDN positive group;IgG1 94.95 ± 0.96;IgG2 1.90 ± 0.33;IgG3 2.15 ± 0.78;IgG4 1.01 ± 0.16 in the HDN negative group. IgG1 is the predominant subclass of the 4 subclasses, except in two cases: IgG1 is35.2%, IgG3 is 63.56% and IgG1 is 77.31%, IgG3 is 20.1%. We use independent-samples T test for equality of means of each subclass, since the significance value of the test is less than 0.05 in IgG1, and more than 0.05 in IgG2, IgG3 and IgG4. We can safely conclude that IgG1 of HDN positive is higher than of HDN negative, and the other three subclasses don't change much between the two groups. The same conclusion can be received from the T test for maternal serum IgG subclasses, though IgG subclasses of HDN positive group are all higher than those of the HDN negative group. Correlation between the concentration of anti- A or B IgG subclasses bound to infants' RBCs and the concentration of anti-A or B IgG subclasses in maternal serum mea...