Relation between plasma endothelin 1 levels and T helper 1: T helper 2 cell immunity in women with preeclampsia

Proportion of peripheral blood and decidual CD4(+) CD25(bright) regulatory T cells in pre-eclampsia

CD4(+) CD25(bright) regulatory T (T(reg)) cells have been identified as a principle regulator of tolerance during pregnancy. In the setting of pre-eclampsia, however, little is known about the dynamics of these cells. In the current study, we determined CD4(+) CD25(bright) T(reg) cells in the peripheral blood using flow cytometry and forkhead box P3 (FoxP3(+)) cells at the placental bed using immunohistochemical staining. Peripheral blood mononuclear cells (PBMC) of 38 pre-eclamptic cases (17 cases Japanese, 21 cases Polish), 40 normal late pregnancy subjects (20 subjects Japanese, 20 subjects Polish), and 21 non-pregnant healthy controls (10 subjects Japanese, 11 subjects Polish) were included. We found the percentage of CD25(bright) cells within the CD4(+) T cell population in PBMC was reduced significantly in both Japanese and Polish pre-eclamptic cases than in normal pregnancy subjects (P < 0.001) and non-pregnant healthy controls (P < 0.001). Also, the percentage of FoxP3(+) cells within CD3(+) T cells in the placental bed biopsy samples of pre-eclamptic cases were decreased compared to those in normal pregnancy subjects. These findings suggest that a decreased number of T(reg) cells was present in pre-eclampsia, and these changes might break the maternal tolerance to the fetus.

Pre-eclampsia is not associated with changes in the levels of regulatory T cells in peripheral blood

PROBLEM

The acceptance of the semi-allogeneic fetus within the maternal environment requires tolerance mechanisms not fully characterized yet. Normal pregnancy is known to be associated with a Th2 profile. Furthermore, regulatory T cells (Tregs) were proposed to regulate the Th2/Th1 balance at early stages of pregnancy. Treg may avoid the shift to a Th1 profile, thus preventing miscarriage. Accordingly, spontaneous abortion is characterized by a Th1 dominance and diminished levels of Treg. The major aim of the present work was to investigate if pre-eclampsia, a late immunological complication of pregnancy, is characterized by similar hallmarks.

METHOD OF STUDY

We measured the surface antigens CD4, CD25, CD8 and CTLA4 in peripheral blood from patients suffering from pre-eclampsia (n = 8) and age-matched patients undergoing normal pregnancies (n = 9) by four-color flow cytometry.

RESULTS

We were not able to find any significant differences in the levels of CD4(+), CD25(+), CD8(+), CTLA4, CD4(+)/CD25(+), CD4(+)/CD25(bright), CD4(+)/CTLA4, CD25(+)/CTLA4, CD4(+)/CD25(+)/CTLA4, CD8(+)/CD25(+), CD8(+)/CTLA4 or CD8(+)/CD25(+)/CTLA4 cell subsets.

CONCLUSIONS

Our data confirm comparable number of Tregs during pre-eclampsia and normal pregnancy in peripheral blood. Other regulatory mechanisms might be involved during late pregnancy.

Th1/Th2 balance in preeclampsia

The syndrome of preeclampsia has previously been ascribed to generalized maternal endothelial dysfunction, poor placentation and excessive maternal inflammatory response. Recent reports suggest that preeclampsia is associated with a Th1 predominant profile and may be considered as a failure of the tolerance system allowing the second physiological trophoblastic invasion. In this review, we discuss that Th1 predominant immunity is closely related to inflammation, endothelial dysfunction and poor placentation.

Cytokine secretion by decidual lymphocytes in transient hypertension of pregnancy and pre-eclampsia

BACKGROUND

Transient hypertension (TH) and preeclampsia (PE) are believed to have different pathophysiology. However, 15-25% of pregnant women initially diagnosed as having TH develop PE. To clarify the immuno-pathogenetical connections between the two syndromes, we studied the pattern of T helper cell (Th)1/Th2 cytokine balance disturbances existing inside maternal decidua in normal pregnancy (NP) and pregnancies complicated with TH and PE.

METHODS

Third-trimester decidual tissue was obtained by curettage of uterine cavity during elective caesarean sections in NP (n = 11), TH (n = 17) and PE (n = 21) patients. Cell suspensions were prepared by an electromechanical dispersal method and centrifugated using a standard gradient sedimentation technique. Isolated lymphocytes were placed in medium (RPMI 1640, 10% fetal calf serum, L-glutamine, penicillin, streptomycin) and cultured for 72 h with or without mitogen phytohaemaglutinine (PHA). The enzyme-linked immunosorbent assay method was used for estimation of interleukin (IL)-2, IL-4, IL-6, IL-10, IL-12 and interferon-gamma (IFN-gamma) in culture supernatant.

STATISTICAL ANALYSIS

The Kruskal-Wallis and the Mann-Whitney U tests were used (p < 0.05).

RESULTS

Both spontaneous and PHA-stimulated secretion of Th2-type cytokines IL-6 and IL-10 was decreased in PE patients compared with TH and NP patients. The concentration of Th1-type cytokine IFN-gamma was increased in patients suffering both from TH and PE.

CONCLUSION

On the base of decidual cytokine secretion, both PE and TH are syndromes of local Th1/Th2 cytokine balance disturbances as compared with NP, and TH seems to be an intermediate step to PE.