Objective: To investigate immunophenotypic characteristics of uterine natural killer (uNK) cells and helper T cell 1/helper T cell 2 (Th1/Th2) immunity in third trimester decidua in preeclampsia.
Methods: The proportions of uNK cell subsets, expression of CD(69) and CD(94) on uNK cells and Th1/Th2 immunity in decidua were determined in 20 cases of preeclampsia patients and 11 cases of normal term pregnancies by flow cytometric analysis.
Results: The percentage of CD(56)(bright)CD(16)(-) uNK cell subset in preeclampsia patients and the controls was (17.3 +/- 11.1)% vs (17.9 +/- 16.8)%, that of CD(56)(dim)CD(16)(+) uNK cell subset was (16.3 +/- 8.7)% vs (16.2 +/- 8.8)%; that of CD(56)(+)CD(69)(+) uNK cells was (37.9 +/- 18.9)% vs (36.8 +/- 19.7)%, that of CD(56)(+)CD(94)(+) uNK cells was (34.9 +/- 15.2)% vs (32.7 +/- 16.2)% and the ratio of CD(56)(+)CD(69)(+)/CD(56)(+)CD(94)(+) was 1.1 +/- 0.2, 1.2 +/- 0.6. No statistical difference was shown in the above values between the preeclampsia patients and controls. The percentage of cytotoxic T cell (Tc) 2 cells was significantly lower in the decidua of preeclampsia patients [(3.0 +/- 1.0)% vs (4.3 +/- 0.9)%, P=0.001], and the ratio of Tc1/Tc2 in preeclampsia patients was significantly higher than that of normal term pregnancies (17.8 +/- 3.4 vs 11.8 +/- 4.6; P=0.001); the ratio of Th1/Th2 was increased (15.1 +/- 2.4 vs 13.2 +/- 3.1; P=0.06).
Conclusions: The immunophenotypic characteristics of uNK cells do not present any significant change in preeclampsia patients. Owing to Tc2 cell decrease, the Th1/Th2 immunity shifts to Th1 type immunity in the decidua, which might contribute to the pathogenesis of preeclampsia.