Severe preeclampsia complicated by HELLP syndrome alters the structure of Hofbauer and syncytiotrophoblast cells: ultrastructural and immunohistochemical study.

Background: Hemolysis, elevated liver enzymes, low platelet count (HELLP) syndrome is generally considered to be a variant or complication of preeclampsia. It is a life-threatening obstetric complication.

Objectives: To evaluate the immunohistochemistry and ultrastructural of syncytiotrophoblastand Hoffbauer cells in placental villi of patients with HELLP syndrome.

Methods: Two groups of patients with a total of 50 full-term human placentas (n = 25 in each group) were assigned as the control (normotensive) and HELLP syndrome. Placental tissue samples were fixed in 10% neutral formalin and paraffin-embedding protocol was performed. We prepared 5 μm sections for histological and immunohistochemical staining. Sections were immunostained with Hoffbauer cell marker CD68. For transmission electron microscopy (TEM), placental tissue samples were fixed in 2.5% buffered glutaraldehyde and then, in 1% osmium tetroxide for routine ultrastructural examinations.

Results: When the HELLP group fetal placental sections were examined, intracytoplasmic edema in syncytiotrophoblast, degenerative vacuoles, and degenerative findings on cell surface membranes were observed. Moreover, villous edema was remarkable. The number of CD68-positive Hoffbauer cells per villus control group sections was 0.23 ± 0.02 and the number of CD68-positive cells per villus in HELLP group placenta sections was 0.83 ± 0.12. The increase in the number of Hoffbauer cells per villus in the HELLP group was significant (P < 0.001). Compared with the control group, there was a significant increase in the number of Hoffbauer cells and syncytiotrophoblasts in the HELLP group, and degenerative changes were also observed in the ultrastructure of these cells.

Conclusions: Pathology of the HELLP syndrome is in relation to CD68-positive placental macrophages.