Perforin-expressing cells during spontaneous abortion.

The metrial gland of pregnant rodents contains an abundant population of natural killer (NK)-like cells called granulated metrial gland (GMG) cells. Since GMG cells express the cytolytic protein, perforin, and since cells with NK activity have been implicated in spontaneous abortions, we have studied the distribution of perforin-containing cells in the uterus of mice undergoing normal pregnancy (Swiss mice) and spontaneous abortions (CBA/J x DBA/2 mice). The distribution of perforin-positive GMG cells was essentially the same near healthy and aborting conceptuses, suggesting that GMG cells are not involved in most cases of spontaneous abortion in this abortion model. Small perforin-positive cells were observed near the aborting conceptus in about 5% of the cases. However, it is not known whether their presence was the result or the cause of abortion.