CHARACTERISTICS OF PERFORIN EXPRESSING LYMPHOCYTES WITHIN THE FIRST TRIMESTER DECIDUA OF HUMAN-PREGNANCY

PROBLEM: The number of perforin (P)-positive cells in decidua of pregn ancy is larger than that observed in any other pathological condition. The aim was to investigate the distribution and the phenotype of P+ c ells. METHOD: Decidual tissue was obtained from the first trimester va ginal termination of pregnancy. Tissue distribution of P+ cells was an alyzed by immunohistochemistry. The method for simultaneous measuremen t of P and cell surface is presented. RESULTS: There is no difference in number and distribution of P+ cells between decidua basalis (DB) an d decidua parietalis (DP). The percentage of pf decidual lymphocytes ( DL) is two times higher than in peripheral blood lymphocytes (PBL) (55 % vs. 27%), and the prevalent phenotype is CD3(-) CD4(-) CD8- CD2(+) ( 95%) CD11c(+) (68%) and CD56(+) (82%). CD56(bright+) DL are also P-bri ght+ and this is the largest DL subpopulation (42.4% DL). Two differen t subpopulations of CD8(+) DL exist: 1) CD8(bright+), which are CD3(+) CD56(-) P- and 2) CD8(dim+), which are CD3(-) CD56(+) P+. CONCLUSION: P expressing DL are prevalently nonclassical NK cells (CD16(-)) with low cytolytic activity but fully equipped with potent cytolytic machin ery (P-bright+). There are no classical cytotoxic lymphocytes (CTL) (C D3(+) CD8(+) P+) in the decidua, and all CD8(+) P+ cells are CD3(-) CD 56(+). The number of P+ cells is even higher in DP in the vicinity of noninvasvie trophoblast, than in DB.