COMPARATIVE-ANALYSIS OF THE IMMUNOPHENOTYPES OF DECIDUAL AND PERIPHERAL-BLOOD LARGE GRANULAR LYMPHOCYTES AND T-CELLS DURING EARLY HUMAN-PREGNANCY

PROBLEM: The functional role of the leukocytes in the decidua is not c lear. They may regulate the maternal immune response to the fetal allo graft. However, the factors controlling maternal and fetal communicati on have not yet been identified. METHOD: A comparative analysis of the phenotypes of decidual and peripheral blood large granular lymphocyte s (LGLs) and T lymphocytes in early human pregnancy was performed on d ecidual tissue and blood samples obtained from ten patients at therape utic abortion. RESULTS: Whereas most of the decidual LGLs were found t o have a CD56(bright++) phenotype, most of the peripheral blood Mt cel ls (90%) showed the classical CD56(dim+) phenotype, and only a small p roportion were CD56(bright+) cells. Another striking difference was fo und in the expression of very rate antigen 1 (VLA-1, CD49a): Almost al l the decidual CD56(bright++) LGLs, but virtually none of the peripher al blood CD56(+) NK cells expressed this antigen. Further differences were found in the expression of CD16, CD44, CD45RA, CD54, and CD57. Th ere were also differences in phenotype between T cells derived from de cidual tissue and those derived from peripheral blood. Approximately 3 1% of the CD3(+) decidual T cells expressed VLA-1, but this antigen wa s virtually absent on peripheral blood T cells. A further difference w as seen in the expression of HLA-DR. This activation antigen was found on 32 +/- 13% of the decidual T cells but only 8 +/- 5% of the periph eral blood T cells. Additionally, the proportion of cells expressing C D38 was higher among decidual than peripheral blood T cells. CONCLUSIO N: The findings suggest that both decidual LGLs and a subset of decidu al T cells are activated and possibly play a role in the control of tr ophoblast growth and placental development.