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Review ofLiterature
next pregnancy or inability to recognize paternal antigens displayed by
the fetus (Walker and Gant, 1997).
Sutherland et al., (1981) postulated that the first pregnancy would
help to immunize the patient against any future pregnancy to the same
partner.
Redman et at, (1978) found a higher incidence of HLA
homozygosity in couples where mothers suffered from preeclampsia.
Chen et al., (1994) found abnormalities of lymphocytes function in
women with pregnancy induced hypertension. Other studies have
demonstrated activation of neutrophils within the maternal circulation
immunocytochemical studies have analyzed neutrophil elastase in term
placenta, decidua & myometrium in women with pregnancy induced
hypertension (Butterworth et al., 1991) . The vascular cell adhesion
molecule (VCAM-I) is elevated in the sera of P.l.H. women and
neutrophil activity partly mediated by this adhesion molecule, which
encourage adhesion to the vascular endothelium (Lyall et al., 1994) .
This could be part of the mechanism of endothelial cell dysfunction.
These changes may act by a direct cellular effects or through release of
cytokines which affect cellular function as they have been shown to affect
the production of prostacyclin and thromboxane in human mononuclear
cells thus affecting the vascular response in preeclampsia (Chen et al.,
1993).
Zhou et al., (1993), demonstated that there was an abnormality in
the expression of the adhesion molecules in the extravillus trophoblast in
pre-eclamptic pregnancies, and there was a failure in the expression of
those associated with successful invasion into the myometrium. This
could explain the secondary invasion that is associated with classical
placental lesion of preeclampsia,
18
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