Effect of sera on the adhesion of natural killer cells to the endothelium in severe pre-eclampsia.

OBJECTIVE

To investigate the effect of serum on the interaction between natural killer (NK) cells and endothelial cells in pre-eclampsia.

METHODS

Seven severely pre-eclamptic patients, five normal pregnant women, and four normal non-pregnant women were included in this study. Freshly isolated NK cells labeled with Chromium-51 were incubated on an endothelial cell monolayer in the presence of patient serum. In regard to the characteristics of adhesive molecules, the endothelial cells were blocked by monoclonal antibodies (mAbs) to intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1); the NK cells were blocked by mAbs to leukocyte function-associated antigen (LFA-1) and very late antigen-4 (VLA-4) before co-incubation. After incubation, the adherent cells were solubilized with 1% Triton X. The lysates were collected and counted in a gamma counter.

RESULTS

The adhesion of NK cells to the endothelium in the normal pregnancy group decreased significantly in comparison to the non-pregnant group (7%vs 72%; P < 0.01). Adhesion in the severe pre-eclamptic group was significantly higher in comparison to the normal pregnant group (44%vs 7%; P < 0.01). The blocking percentages of mAbs on NK adhesion in the severe pre-eclampsia group were 49 +/- 4% to LFA-1, 61 +/- 48%, 67 +/- 39% to VLA-4, ICAM-1, and 68 +/- 7% to VCAM-1.

CONCLUSION

Sera from normal pregnant women suppress the adhesion between NK cells and endothelial cells, whereas the suppressive effect of sera from pre-eclamptic patients has a diminished affect.