29 November 2004
NK Cell Testing & Treatment Of No Benefit
Tests and treatments provided by fertility clinics for women suffering recurrent miscarriage and infertility have no scientific rationale and are linked with known risks to mother and fetus, warn researchers writing in the British Medical Journal. Many clinics are offering women tests to measure the number and activity of natural killer (NK) cells circulating in their blood. These cells are found in the womb and accumulate in large numbers during early pregnancy, but their function is completely unknown.
The tests are based on the hypothesis that women with fertility problems have raised levels of NK cells. As a result, many women are offered treatments, such as steroids or immune suppressant drugs, to reduce the levels of NK cells. But the researchers argue that these tests do not provide useful information about what is happening in the uterus and the treatments are not appropriate as they are associated with known risks to mother and fetus. Additionally, recent guidelines from the Royal College of Obstetricians and Gynaecologists has concluded that there is no evidence to show they are beneficial.
Understanding the function of uterine NK cells is certainly a major challenge in human reproduction, says the Royal College of Obstetricians and Gynaecologists. However, until more is known about their role in normal pregnancy, there is no evidence of any benefit in offering NK cell testing in women with recurrent miscarriage and infertility outside of properly controlled studies. "This unfortunate group of women are particularly vulnerable to financial exploitation, and of being exposed to powerful treatments that have, as yet, no rational scientific basis," the researchers conclude.