EXPRESSION OF MEMBRANE FORM OF THE PREGNANCY-ASSOCIATED PROTEIN TJ6 ON DECIDUAL LYMPHOCYTES IN THE FIRST TRIMESTER OF PREGNANCY

TJ6, a newly described protein produced locally in the uterine decidua during pregnancy, may be involved in maintaining a unique immunologic al environment at the maternal-fetal interface. The aim of this study was to determine whether TJ6 is expressed as membrane form on decidual lymphocytes (DL), to define the phenotypes of TJ6m (membrane form TJ6 ) expressing cells and to analyze the fluorescence intensity of TJ6m e xpression. Peripheral blood lymphocytes (PBL) and DL were obtained fro m first trimester pregnancies undergoing elective termination and immu nophenotyped for TJ6m and other cell surface antigens (CD3, CD8, CD19, CD56, CD16) by flow cytometry. This is the first study showing that T J6 molecules are present on decidual lymphocytes in human pregnancy. T J6m expression on PBL was not different from that of DL. However, a si gnificantly higher percentage of double positive (TJ6m(+)CD3(+), TJ6m( +)CD8(+), TJ6m(+)CD19(+)) cells were found in PBL when compared to DL. The average fluorescence intensity (AFI) for the TJ6m marker among ce lls with CD8(+), CD19(+) and CD56(+) double positive was significantly higher in DL as compared with those of PBL. The AFI for granularity o f double positive DL was significantly higher than observed in PBL.