I. Szigetvari

Placental site trophoblastic tumor. Clinical and pathological report of two cases.

Placental site trophoblastic tumor (PSTT) is the rarest disease of the gestational trophoblast. Our two cases will be interesting not only because of the rarity of the disease, but because both were recognized before operation. Since the tumor cells are lined up tightly side by side, this disease must be distinguished primarily from tumors of epithelial origin. The authors highlight that the diagnosis should rely on intense hPL-positivity as well as the ultrastructural image of the tumor. In histologically equivocal cases, the determination of hPL, hCG, and MIB-1 immunologic markers can be recommended as routinely performed morphological examinations. Serum hCG monitoring is recommended to follow the evolution of the tumor.

Temporary Tolerance or Suppressive Regulation Induced By Non MHC Alloantigens in Transplantation and Pregnancy

A special type of tolerance or suppressive regulation will be reported, which can be characterized by the complementary participation of two alloantigen systems; the major histocompatibility complex, and either a minor histocompatibility or certain type of differentiation antigen (secondary, subordinated) alloantigen system of functional importance. There are representative experimental observations on this phenomena, from which one characteristic model, reported by Hutchinson and Morris (Hutchinson and Morris 1987) is explained. Prior to kidney transplantation between RTL incompatible rats recipients were transfused with blood obtained from various strains characterized by either matching or mismatching with the transfusion and organ donor or recipient strain in the minor histocompatibility system. The matching between transfusion and kidney donor and a mismatching between transfusion donor and organ recipient as regards minor histocompatibility alloantigen system has to be emphasized as a new requirement. No similar situation has been reported in human beings. However, the induction of tolerance by transfusion in certain models is a well established phenomena. The importance of class II antigen matching between transfusion donor and recipient were outlined and proved in series of clinical observations based on in vivo and in vitro parameters including cytotoxic antibody production, MLC, cytotoxic precursor cell function and kidney survival (Lagaay et al. 1989, Claas et al 1991, van Rood and Claas 1990, de Waal and van Twuyer 1991).