Why do certain diseases go into remission during pregnancy?

http://www2.med.umich.edu/prmc/media/newsroom/details.cfm?ID=1632

June 16, 2010

ANN ARBOR, Mich. -- During pregnancy, many women experience remission of autoimmune diseases like multiple sclerosis and uveitis. Now, scientists have described a biological mechanism responsible for changes in the immune system that helps to explain the remission.

The expression of an enzyme known as pyruvate kinase is reduced in immune cells in pregnant women compared to non-pregnant women, according to Howard R. Petty, Ph.D., biophysicist at the University of Michigan Kellogg Eye Center and Roberto Romero, M.D., of the National Institutes for Health.

The study, which appears online ahead of print in the August issue of the American Journal of Reproductive Immunology, also reports that expression of the enzyme is lower in pregnant women compared to those with pre-eclampsia, a condition with inflammatory components.

The study is significant because the newly discovered mechanism points to a pathway that could be targeted for treatment. “It may be possible to design drugs that mildly suppress pyruvate kinase activity as a means of replicating the immune status of normal pregnancy,” says Petty.

In addition to pre-eclampsia, he believes that rheumatoid arthritis, type 1 diabetes, and uveitis may eventually yield to similarly designed drugs.

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