[Fwd: Steroid may prevent repeated miscarriages - reduces uterine NK cell number]

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Steroid may prevent repeated miscarriages

* 15:50 20 June 2005

* NewScientist.com news service

* Rowan Hooper

http://www.newscientist.com/article.ns?id=dn7543

A steroid may prevent repeated miscarriages, says a UK researcher who

has shown the chemical can reduce the number of " killer cells " accused

of causing miscarriages. But other experts say clinical trials to

explore this would be too risky, not least because the exact role of

these cells is unknown.

The controversy revolves around a type of immune cell called a natural

killer (NK) cell. Although no one knows what the function of NK cells

is, they have been implicated in the implantation of embryos in the

womb. However a few small studies suggest that high numbers of NK cells

increase the risk of miscarriage.

Some private clinics already offer treatments such as steroids and

immunosuppressants to reduce the number of NK cells in women who have

suffered recurrent miscarriages. But claims of dramatic results, and the

publicity given to them, have been attacked by fertility experts who

argue that there is no scientific basis to the treatments.

" The link between the number of NK cells and their function is hard to

make because we don't know what they do, " says Moffett of the

University of Cambridge.

Confusingly, there are two types of NK cells: peripheral NK cells in the

blood, and uterine NK cells in the lining of the womb. Some clinics

estimate the number of uterine NK cells is based on the number of

peripheral NK cells. But Moffett says that is like using the number of

black taxis in London's Trafalgar Square to estimate the number of red

taxis on motorways.

Multiple miscarriages

The latest study addresses this criticism. Siobhan Quenby of the

University of Liverpool, UK, took samples from the wombs of 110 women

who were not pregnant but had suffered an average of six miscarriages

each. In 33 of these women, uterine NK cells accounted for at least 5%

of the cells in the sample, while in the other women they accounted for

less than 5%.

Quenby asked the 33 women to take the steroid prednisolone, which is

used to treat conditions such as asthma and eczema. NK cells have

steroid receptors on their surface, and some studies suggest that

steroids such as prednisolone knock out the receptors.

Twenty-nine of the women took 20 milligrams of prednisolone daily for 21

days from the start of their menstrual cycle. By day 21, uterine NK cell

numbers had dropped by an average of 6% compared with women not taking

the steroid, Quenby told the European Society for Human Reproduction and

Embryology meeting in Copenhagen, Denmark, on Monday.

" Desperate " participation

The trial was originally going to stop at this point, but all the women

demanded to be allowed to continue on the drug when they were told the

results. " They were desperate for it, " says Quenby. Six of the women

have since become pregnant, with one ending in miscarriage and two in

births. The remaining three pregnancies are now beyond the point at

which most miscarriages occur.

Quenby stresses that the results are preliminary and do not prove that

an excess of uterine NK cells cause miscarriages. " We urgently need

clinical trials, " she says.

But Moffett is not so sure. " Steroids have serious side effects and

there may be additional risks to women in early pregnancy, " she says.

" We're not yet ready for clinical trials because we don't know enough

about what NK cells do. It's too premature to say: 'right, let's give

everyone prednisolone'. "

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Weblinks

* University of Liverpool

<http://www.liv.ac.uk/FacultyMedicine/root/school%20of%20reproductive%20 & %20deve\

lopmental%20medicine/index.htm>

*

http://www.liv.ac.uk/FacultyMedicine/root/school%20of%20reproductive%20 & %20devel\

opmental%20medicine/index.htm

<http://www.liv.ac.uk/FacultyMedicine/root/school%20of%20reproductive%20 & %20deve\

lopmental%20medicine/index.htm>

* Moffett, University of Cambridge

<http://www.path.cam.ac.uk/pages/moffett/>

* http://www.path.cam.ac.uk/pages/moffett/

* European Society for Human Reproduction and Embryology

<http://www.eshre.com/emc.asp?pageId=195>

* http://www.eshre.com/emc.asp?pageId=195

*

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