The fact that depletion of CD8+ T cells abolished anti-4-1BB-mediated fetal loss and complement deposition in the placenta, while depletion of CD4+ T cells did not (Table 2 and Figure 3F, H), is inconsistent with a previous report that CD8+ T cells prevented spontaneous abortion in DBA/2-mated CBA/J mice [27], but does agree with the observation that the Th1 cytokine profile induces miscarriages in humans and mice [28]. This evidence concerns the gene CD4 and abortion.