Occurrence of Eosinophilic Granulocytes in the Decidua of Placentas With Perinatal Clinical Findings.

INTRODUCTION

Inflammatory and immunologic homeostasis in the basal plate of the placenta is essential for the fetal development and growth, since the fetus immunologically constitutes a semi-allograft. Bone marrow derived eosinophilic granulocytes are usually not found in the basal plate.

MATERIALS AND

METHODS

We retrospectively analyzed the occurrence of eosinophilic granulocytes in the basal plate of singleton placentas and investigated clinical and pathologic-anatomic associations.

RESULTS

In 5 singleton placentas (0.3% of all investigated cases from the archive) eosinophilic granulocytes were detectable. All these cases also displayed chronic deciduitis. Two cases had a clinical history of substitution therapy with methadone, in 2 instances the mothers had a history of atopic diseases, and 1 mother had a SARS-CoV-2-infection during pregnancy.

CONCLUSIONS

The infiltration of eosinophilic granulocytes in the decidua is a rare feature of placentas with perinatal clinical findings. Strikingly, all 5 affected cases also presented with chronic deciduitis. This may hint at a contribution of the eosinophilic infiltrate to a non-infectious pathologic inflammatory process with an increased risk for perinatal complications.