No difference in natural killer or natural killer T-cell population, but aberrant T-helper cell population in the endometrium of women with repeated miscarriage

BACKGROUND: The aim of this study was to assess the natural killer (NK) cell and natural killer T (NKT) cell populations and cytokine expression of T-helper (Th) cells in the endometrium of women who suffered from unexplained repeated miscarriage (RM). METHODS: The percentages of NK cells, NKT cells and CD4(+) cells expressing intracellular interferon (IFN)-gamma, interleukin (IL)-4 and tumour necrosis factor (TNF)-alpha were measured by flow cytometry in the endometrium of 20 RM women and 17 fertile control women in the mid-luteal phase of the menstrual cycle. RESULTS: No significant differences in CD56(+) NK cell or CD3(+)CD4(-)CD8(-)Valpha24(+)Vbeta11(+) NKT cell percentages were found between RM and control women. However, in RM women compared with control women, the percentages of CD3(+) cells (mean 40.3 versus 56.5%), CD4(+)IFN-gamma(+) cells (28.4 versus 39.5%) and CD4(+)TNF-alpha(+) cells (32.9 versus 45.8%) were significantly lower. The Th1/Th2 cell balance in RM women did not differ from that of controls. CONCLUSIONS: Immunodystrophism detected as diminution of the Th cell population rather than Th1 predominance, NK cell or NKT cell accentuation in the endometrium might underlie the pathophysiology of unexplained RM. This finding provokes an additional controversy on the Th1/Th2 balance concerning RM aetiology.