Human decidual cells activity in women with spontaneous abortions of probable CMV aetiology during the first trimester of gestation. An immunohistochemical study with CMV-associated antigen.

Aim: To determine the expression of CMV-associated antigen in the human decidual endometrial stromal cells in spontaneous abortions with no evidence of maternal relapse during the first trimester of gestation.

Experimental Design: We examined 15 placentas resulting from intrauterine fetal death after spontaneous abortion during the 8th, 10th, and 12th week of gestation respectively, and in which CMV reactivation was ruled out from serological evaluation of the pregnant women at admission, versus equal controls after voluntary abortion following well-documented maternal viral recurrence. In addition, a panel of monoclonal antibodies for the identification of leukocytes (CD45/LCA), B-lymphocytes (CD20/L-26), and T-lymphocytes (CD45RO/UCHL1), was performed. All women received hormonal medication to support gestation, in the cases of spontaneous abortions.

Results: Immunohistochemical examination using a specific antibody against cytomegalovirus showed large multinucleated infected cells with intranuclear inclusions, located primarily in the decidual stroma within a lymphoplasmacytic infiltrate in the cases of spontaneous abortions. No evidence of infection was observed in the chorionic villi. In the cases of voluntary abortions same findings were observed in the relevant areas, and a strong evidence of infection was observed in the chorionic villi.

Conclusion: This study demonstrates 1) that the decidual endometrial stromal cells can express the CMV-associated antigen prior to serological manifestation of the viral replication, 2) the expression of the antigen is higher in cases of hormonal administration to support gestation. In these cases a mild mononuclear infiltrate of UCHL1 (T marker) positive cells, accompanies the CMV-associated antigen positive cells.