PROBLEM: The question of how trophoblastic and malignant cells evade immunologic recognition and rejection by their host was studied. METHOD OF STUDY: A literature review was conducted.
RESULTS: Trophoblastic and malignant cells share a number of similarities. These include a lack of major histocompatibility complex antigen expression, resistance to lysis by natural killer cells, T-helper cell-2 (TH2)-biased response, prostaglandin E production, and response to transforming growth factor beta. In addition, the analogies between trophoblastic and malignant cells extend into immunotherapy in which anti-idiotype therapy has a viable role in the prevention of pregnancy loss and the treatment of cancer. CONCLUSIONS: Trophoblastic and malignant cells use a number of similar mechanisms to resist rejection by their host. By using similar strategies these cells are able to successfully co-exist in an immunologically hostile environment.