Alterations in cellular immunity of normal pregnant women: Increased percentages of peripheral large granular lymphocytes during early pregnancy

Abstract

Peripheral blood lymphocytes including large granular lymphocyte subsets (CD56+, CD56+CD8+, CD56+CD8-), T lymphocyte subpopulations (CD2+, CD3+, CD4+CD29+, CD4+CD45RA+, CD8+) and B-lymphocytes (CD19+) were analyzed in 46 women with normal pregnancies by flow cytometry. When compared with the control group, consisting of nonpregnant fertile women (n=11), the total CD56+, CD8+ and the CD56+CD8+ cell percentages were increased while the CD4+ cell percentages and the CD4+/CD8+ ratios were found to be decreased in the first and second trimesters. Furthermore, the CD19+, CD4+ and CD4+CD29+ cell percentages, and correspondingly the CD4+/CD8+ and CD4+CD29+/CD4+CD45RA+ ratios were decreased while the total leucocyte counts were increased during the third trimester. On the other hand, in the first trimester the percentage of CD4+CD29+ cells was lower than the control group and the CD3+ cell percentage was decreased and an increase was observed in the percentage of CD56+CD8- cells compared to the second trimester. No statistical differences has been found between other parameters. These physiological changes may play an important role in implantation and in the natural defence against infections during early pregnancy and in protection of the fetus allograft in late pregnancy.