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Keywords:

  • Cytokine;
  • implantation failure;
  • IVF/ET;
  • recurrent spontaneous abortion;
  • T helper 1;
  • T helper 2

PROBLEM: We aimed to investigate absolute counts of intracellular T helper 1 (Th1) and Th2 cytokine expressing T-cell subpopulations in women with three or more recurrent spontaneous abortions (RSA), multiple implantation failures after in-vitro fertilization and embryo transfer (IVF/ET) (three or more) or during normal pregnancy.

METHOD OF STUDY: Absolute cell counts and percentages of CD3+, CD3+/CD4+, and CD3+/CD8+ T-cell populations expressing intracellular cytokines [interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-4 and IL-10] was studied by four-color flow cytometry in 15 RSA and 13 implantation failure patients. Eighteen fertile non-pregnant and 47 normal pregnant women were also compared with regard to intracellular cytokine expression.

RESULTS: Interleukin-10 producing CD3+/CD8+ T-cell counts were significantly lower in women with RSA (P < 0.05) and implantation failures (P < 0.05), and TNF-α producing CD3+/CD4+ T-cell counts were higher in women with RSA (P < 0.05) and implantation failures (P < 0.005) than those of non-pregnant fertile controls. During normal pregnancies, first trimester IL-4 expressing CD3+, CD3+/CD4+ T-cell counts (P < 0.05) and IFN-γ expressing CD3+ T-cell counts (P < 0.05) were significantly higher than those of third trimester (P < 0.05). First trimester TNF-α expressing CD3+/CD8+ T-cell counts were significantly higher than those of second and third trimester women (P < 0.05). However, there are no differences in cytokine expression between non-pregnant and first trimester pregnant women.

CONCLUSION: Absolute counts of IFN-γ, IL-4, and TNF-α expressing T cells decrease with the progress of gestation (third trimester) during normal pregnancies. In women with implantation failures, absolute cell counts of TNF-α expressing CD3+/4+ cells reflects the presence of dominant Th1 immune response. A significantly increased Th1 cytokine expression may be the underlying immune etiology for reproductive failures.