IgG/placental alkaline phosphatase complexes in Rh-incompatible pregnancy with fetal hydrops

A case of severe Rh (D) alloimmunization treated by intensive plasma exchange and high-dose intravenous immunoglobulin

BACKGROUND

In extremely severe Rh (D) alloimmunization, during pregnancy, early diagnosis and treatment is essential to avoid hydrops fetalis. Intrauterine transfusion (IUT) is of utmost importance in the prevention of fetal anemia but it is usually feasible only after 20 weeks of pregnancy. Therefore, additional treatment options in early pregnancy are needed.

STUDY DESIGN AND METHODS

A 27-year-old severely D+C immunized woman was admitted at 8 weeks of gestation in her fifth pregnancy with an extremely high concentration of anti-D. Her first pregnancy was uneventful but resulted in D+C alloimmunization. The next two pregnancies were unsuccessful, because of hydrops fetalis resulting in fetal death in pregnancy week 20 and 24, respectively, despite treatment with high-dose intravenous immunoglobulin (IVIG) and IUT treatment. A fourth pregnancy was terminated with legal abortion. The patient was eager and persistent to accomplish a successful pregnancy. Therefore, a combination of treatments consisting of plasma exchange (PE) three times/week and IVIG 100g/week was started in pregnancy week 12. PE was performed 53 times and totally 159L of plasma was exchanged.

RESULTS

The anti-D concentration was 12mug/mL (IAT titer 2000) before start of treatment by PE and IVIG in pregnancy week 12. The concentration of anti-D was gradually reduced to approximately 3mug/mL after only two weeks of treatment and was maintained at that level until pregnancy week 22. In pregnancy week 26 and 27, signs of hydrops were detected by ultrasonography and IUT were performed at each occasion. Sectio was inevitable at pregnancy week 28+1 and a male baby was born: Hb 58g/L (cord sample) and 68g/L (venous sample); weight 1385g; Apgar score=4-5-7; Bilirubin 56-150mmol/L (4h). Exchange transfusion was performed on day two and day five. Phototherapy was also implemented for eight days. The newborn's recovery thereafter was uneventful and complete.

CONCLUSION

A combination of PE and IVIG may be an efficient treatment possible to start in early pregnancy in patients with extremely severe Rh (D) alloimmunization, with a history of hydrops fetalis in previous pregnancies.

Placental transport of maternal immunoglobulin G in pregnancies at risk of Rh (D) hemolytic disease of the newborn

PROBLEM

The following questions were addressed: Is the placental transport of immunoglobulin (Ig)G, IgG1, and IgG3 diminished in pregnancies at risk of hemolytic disease of the newborn? Is the placental transport of IgG, IgG1, and IgG3 correlated with the hemoglobin concentration in the fetus and AutoAnalyzer (AA) quantitations of maternal anti-D?

METHOD OF STUDY

IgG concentrations were determined retrospectively in 41 paired fetal/maternal (f/m) samples in 31 Rh (D) alloimmunized pregnancies. IgG1 and IgG3 concentrations were determined in those 23 cases in which the results of fetal hemoglobin concentration and quantitations of maternal anti-D were available. The results were compared with values found in normal pregnancy and correlated with maternal anti-D AA quantitations and fetal hemoglobin concentrations.

RESULTS

Fetal IgG, IgG1, and IgG3 concentrations, and the corresponding fetomaternal ratios in Rh (D) alloimmunized pregnancies, increased with gestational age according to the following formulas (obtained by simple regression): Fetal IgG = -8.846 + 0.491.gestational age (GA), (R2 = 0.544); fetal IgG = 10.021 + 0.46.GA (R2 = 0.463); fetal IgG3 = -0.865 + 0.039.GA, (R2 = 0.327); f/m IgG = -1.006 + 0.054.GA, (R2 = 0.557); f/m IgG1 = -1.876 + 0.085.GA, (R2 = 0.654); f/m IgG3 = -0.199 + 0.026.GA, (R2 = 0.146).

CONCLUSIONS

The placental transport of IgG, IgG1, and IgG3 in women with Rh (D) immunizations is not diminished compared with normal pregnancy. However, AA quantitations of anti-D are inversely correlated with f/m IgG ratio, f/m IgG1 ratio, and fetal IgG and IgG1 concentrations (P = 0.002, P = 0.004, P = 0.02, and P = 0.02 respectively). The placental transport of IgG3 is significantly higher in pregnancies at risk of hemolytic disease of the newborn compared with IgG3 concentrations in normal pregnancy.

Biology of human alkaline phosphatases with special reference to cancer

The current information on the cloning and sequencing of four alkaline phosphatase genes (PLAP, GCAP, IAP, TNAP) has been reviewed. It has provided insights into their evolutionary history and the mechanisms of catalysis and of uncompetitive inhibition. The oncodevelopmental biology of the germ cell and its excessive GCAP eutopic expression in neoplasia are noted, and there is reason to suggest that the enzyme may serve to guide migratory cells and to transport specific molecules such as fat and immunoglobulins across membranes. The hyperexpression of all four genes has been observed in various human tumors and in their cell lines, particularly cancers of the testis and ovary. The membrane APs have been investigated as targets for immunolocalization and immunotherapy.

New antibody in severe rhesus incompatible pregnancies: IgG-kappa antiplacental alkaline phosphatase

As already found in other various diseases, a macromolecular alkaline phosphatase complex (HMW-AP) was also found in sera of two severe Rhesus-incompatible pregnancies complicated by ascites and fetal hydrops at delivery. This atypical complex was detected and isolated by agarose gel electrophoresis. Immunoelectrophoresis and heat inactivation of this HMW-AP complex revealed that it consisted of IgG of the kappa type and placental AP isoenzyme. The transitory presence of this immuncomplex is discussed. However, in all women with Rh-immunized complicated pregnancies, significant variations of neutrophil and serum AP activities were observed. A fall in AP activity and the presence of an antiplacental AP antibody in serum of women with complicated Rh immunization should be of value in assessing the prognosis of the disease.