Maternal anti-placental cell-mediated reactivity and spontaneous abortions.

PROBLEM: Does Th1/Th2 balance determine pregnancy outcome, and if so, what determines Th1/Th2 balance in pregnancy?

METHOD: Review and synthesis of existing data.

RESULTS

A bias toward Th1 is strongly correlated with pregnancy failure in mice and humans. Pregnancy usually shifts the balance toward Th2 and placental factors/progesterone and progesterone-stimulated CD8+ T cell production of suppressor factor; TGFbeta2 and IL4/10 may be responsible. The bias toward a Th1 response may result from intracellular parasitic infection and other as yet undefined factors.

CONCLUSION

The Th1/Th2 balance thesis appears to be valid.