Anti-TPO antibodies diffusion through the placental barrier during pregnancy.
BACKGROUND
Hashimoto's thyroiditis is the principal aetiology of hypothyroidism with presence of anti-thyroperoxidase antibodies (anti-TPO). The association between anti-TPO and foeto-placental complications has been observed in previous studies. To go further in the understanding, the current study compares the level of anti-TPO in maternal blood and in the cord blood of her fetus at the moment of childbirth to demonstrate the passage of anti-TPO through the placenta barrier.


RESULTS
This study was realised in a maternity ward located in the Northern district of Paris, France from 2006 to 2007. Women with normal pregnancy were included in a first study and only women with no abnormal thyroid dosage at baseline and tested positive with anti-TPO were prospectively enrolled. Maternal blood samples were collected in the third trimester and at the arrival to the ward when patients came to deliver. After delivery, cord blood sample was collected. Pearson's correlation coefficient was computed. 5941 patients delivered in the ward during the study, 33 pregnant women were included. We found a correlation between the anti-TPO levels in maternal and in the cord blood of their fetus with a correlation coefficient of 0.98 and a p-value<0.001.


CONCLUSIONS
This is the first demonstration of the free passage through the placental barrier of anti-TPO from the mother to the fetus at the moment of childbirth. These findings can be extrapolated all along pregnancy and open the door to a direct action of the anti-TPO on fetus and to a possible action on the fetal thyroid.
Paris Diderot, Université Paris VII, Paris, France ; Department of Gynecology and Obstetrics, Beaujon-Bichat Hospital, AP-HP, Clichy, France.
Jérémy
J
Seror
Paris Diderot, Université Paris VII, Paris, France ; Department of Gynecology and Obstetrics, Beaujon-Bichat Hospital, AP-HP, Clichy, France.
Gaëlle
G
Amand
Department of Hormonal and Metabolic Biology, Cochin Hospital, AP-HP, Paris, France.
Jean
J
Guibourdenche
Paris Diderot, Université Paris VII, Paris, France ; Department of Gynecology and Obstetrics, Beaujon-Bichat Hospital, AP-HP, Clichy, France.
Pierre-François
PF
Ceccaldi
Paris Diderot, Université Paris VII, Paris, France ; Department of Gynecology and Obstetrics, Beaujon-Bichat Hospital, AP-HP, Clichy, France.
Dominique
D
Luton
D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D004058:Diffusion; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D005602:France; D006801:Humans; D007231:Infant, Newborn; D007453:Iodide Peroxidase / Q000276:immunology*; D008431:Maternal-Fetal Exchange; D010920:Placenta / Q000098:blood supply*; D021041:Placental Circulation; D011247:Pregnancy; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
D001323:Autoantibodies; D014284:Triiodothyronine; D013972:Thyrotropin; D007453:Iodide Peroxidase; D013974:Thyroxine