Paternal leukocytes selectively increase secretion of IL-4 in peripheral blood during normal pregnancies: demonstrated by a novel one-way MLC measuring cytokine secretion.
OBJECTIVE
It has been proposed that immune responses in normal pregnancy are Th2-like, thereby protecting the fetus and placenta from being rejected. Some studies have shown Th2-deviated systemic responses to different antigens and mitogens. The aim of this study was to demonstrate the specific T cell cytokine responses directed toward paternal histocompatibility leukocyte antigen (HLA), because this is the most prominent target for rejection of the feto-placental unit.


METHODS
A novel one-way mixed leukocyte culture (MLC) combined with the detection of cytokine secretion with a sensitive ELISPOT assay was developed. Peripheral blood from 11 pregnant women was investigated with respect to allo-reactivity toward paternal leukocytes and pooled leukocytes from unrelated blood donors. This was done at three different occasions during pregnancy and 8 weeks after delivery. Nine age-matched non-pregnant women served as controls.


RESULTS
In the second and third trimesters of pregnancy significantly larger numbers of IL-4-secreting cells (Th2) were induced by paternal leukocytes as compared to unrelated leukocytes.


CONCLUSIONS
The findings indicate a selective immune deviation toward Th2, which may protect the fetus from rejection and thus may be an important homeostatic mechanism in normal pregnancies.
Ekerfelt
C
C
Department of Neurology, University Hospital, Linköping, Sweden.
Matthiesen
L
L
Berg
G
G
Ernerudh
J
J
D000328:Adult; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000097:blood / Q000378:metabolism; D015847:Interleukin-4 / Q000097:blood* / Q000378:metabolism; D007962:Leukocytes / Q000276:immunology*; D007959:Lymphocyte Culture Test, Mixed / Q000379:methods; D008297:Male; D008431:Maternal-Fetal Exchange / Q000276:immunology; D010334:Paternity; D049590:Postpartum Period / Q000097:blood / Q000276:immunology; D011247:Pregnancy / Q000097:blood / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology; D013997:Time Factors
D015847:Interleukin-4; D007371:Interferon-gamma