Characterization of endometrial T lymphocyte subpopulations in spontaneous early pregnancy loss.

T lymphocyte subpopulations were compared in normal first trimester human decidua and in decidua associated with spontaneous abortion. Cryostat sections were labelled using a panel of monoclonal antibodies specific for CD3, CD8, CD4 and for the alphabeta and gammadelta heterodimers of the T cell receptor using an avidin-biotin complex peroxidase method. All the endometrial T cell subsets which have been demonstrated in normal early pregnancy were detected in similar numbers and proportions in spontaneous abortion. The findings suggest that adverse pregnancy outcome is not influenced by altered proportions of T cell subpopulations; nevertheless, the possibility remains that these cells may have an altered antigenic phenotype in spontaneous abortion which could contribute to pregnancy success or failure.