Fetal and embryonic hemoglobins in erythroblasts from fetal blood and fetal cells enriched from maternal blood in pregnancies complicated by maternal diabetes mellitus.
OBJECTIVE
To determine whether there is a delay or reversal in switch mechanisms from embryonic (epsilon and zeta) to fetal (gamma) hemoglobins accompanying the erythroblastosis in fetuses of diabetic mothers, and whether the increased erythroblast count in the fetal blood is associated with an increase in fetomaternal cell trafficking.


METHODS
Fetal and maternal blood samples were obtained from 11 fetuses and five pregnant women in pregnancies complicated by maternal diabetes mellitus. Blood samples were also taken as controls from 35 fetuses and 33 mothers. Fetal erythroblasts were isolated by triple density gradient centrifugation and magnetic cell sorting with anti-CD71 antibody. Fluorescent antibodies were used to immunostain for gamma (gamma), epsilon (epsilon) and zeta (zeta) hemoglobin chains. In the maternal samples, fluorescence in situ hybridization for X and Y chromosomes was also carried out, to confirm the presence and proportion of enriched fetal cells from the maternal blood.


RESULTS
In both fetal and maternal blood the median percentages of erythroblasts positive for gamma-globin, epsilon-globin and zeta-globin chains were significantly higher in fetuses of diabetic mothers compared to controls (fetus, gamma-globin, 76 vs. 64%, p < 0.0001; epsilon-globin, 4 vs. 0%, p < 0.0001; zeta-globin, 4 vs. 0%; p < 0.0001; mother, gamma-globin, 14 vs. 1%, p < 0.0005; epsilon-globin, 0.25 vs. 0%, p < 0.0003; zeta-globin, 0.2 vs. 0%, p < 0.0003). The median percentage of cells with Y signals in maternal blood was also higher in diabetic pregnancies compared to normal controls (7.5 vs. 1%, p < 0.002).


CONCLUSIONS
The findings suggest that the fetal erythroblastosis in diabetic pregnancies is accompanied by a delay in the switch from embryonic to fetal hemoglobin chains. In addition, it is associated with an increase in fetomaternal cell trafficking.
Al-Mufti
R
R
Harris Birthright Research Centre For Fetal Medicine, King's College London School of Medicine, King's College Hospital, London, UK.
Hambley
H
H
Farzaneh
F
F
Nicolaides
K H
KH
D016022:Case-Control Studies; D002452:Cell Count; D041322:Chromosomes, Human, Y; D004622:Embryo, Mammalian / Q000737:chemistry* / Q000166:cytology; D004900:Erythroblasts / Q000737:chemistry* / Q000166:cytology; D005260:Female; D005312:Fetal Blood / Q000737:chemistry* / Q000166:cytology; D005319:Fetal Hemoglobin / Q000032:analysis*; D005331:Fetomaternal Transfusion / Q000097:blood*; D005914:Globins / Q000032:analysis; D006801:Humans; D008297:Male; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000097:blood*; D012044:Regression Analysis
D005914:Globins; D005319:Fetal Hemoglobin