A CD16+CD56DIM NK cell increase may lead to idiopathic infertility
(Assisted Reproduction-January 22, 2004)

"One-fifth of all in vitro fertilization (IVF) patients suffer from idiopathic infertility. A low fertilization rate is one of the most characteristic features of IVF in this group, probably caused by oocyte dysfunction," scientists writing in the Journal of Reproductive Immunology report.

"We speculate that an altered lymphocyte profile in follicular fluid (FF) may affect oocyte function and thus play a role in idiopathic infertility. Therefore, we compared levels of lymphocyte populations present in FF of 11 patients with idiopathic infertility (study group) with 29 patients in the control group, i.e. severe male factor infertility (n=17) or tubal factor infertility (n=12)," the scientists observed.

"Triple color flow cytometry was used to discriminate between T cells and NK cell subpopulations. In the idiopathic infertility group, a shift from T to NK cells was observed in FF, as compared to the control group, caused mainly by a significantly higher level of NK cells, at 20.3% and 13.6% (p< 0.05), respectively.

"This high level of NK cells was due to a rise of the CD16+CD56DIM NK cell subset. In peripheral blood, the NK cell levels showed a similar, although not significant trend (p=0.08)," wrote H.G.M. Lukassen and coauthors.

The researchers concluded: "As the CD16+CD56DIM NK cell subpopulation is known for its cytotoxic properties, this subpopulation may negatively affect folliculogenesis and oocyte maturation, reflected by a diminished fertilization rate in the idiopathic infertility group. An altered lymphocyte profile in FF could therefore influence fertility in these patients."

Lukassen and colleagues published their study in Journal of Reproductive Immunology (The proportion of follicular fluid CD16+CD56DIM NK cells is increased in IVF patients with idiopathic infertility. J Reprod Immunol, 2003;60(1):71-84).

Additional information can be obtained by contacting H.G.M. Lukassen, University Nijmegen, Med Center, Dept Obstetrics & Gynecology, POB 9101, NL-6500 HB Nijmegen, Netherlands.

The publisher of the Journal of Reproductive Immunology can be contacted at: Elsevier Science Ireland Ltd., Customer Relations Manager, Bay 15, Shannon Industrial Estate, Co Clare, Ireland.

The information in this article comes under the major subject areas of Hematology, Immunology, NK Cell Subsets, Idiopathic Infertility, Follicular Fluid, Diagnostics, Obstetrics, and Reproductive Medicine. This article was prepared by Women's Health Weekly editors from staff and other reports.

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