Studying the Autoimmune Disease Puzzle:

“For reasons that researchers are just

beginning to understand, women are at a

much greater risk than men of falling prey

to an autoimmune disease, in which the

body’s immune system turns paranoid and

begins to attack one or more of the body’s

organs.

The list of autoimmune diseases is long and

varied, composed of more than 80

disorders afflicting virtually every sector of

mortal flesh and function: the liver, the

kidneys, the adrenal glands, the ovaries,

the pancreas, the skin, the joints, the

muscles, the myelin sheaths that buffer the

nerves, the salivary ducts that spit, the tear

ducts that weep.”

One recent finding that mother and fetus exchange body cells that can persist in each other’s circulation in a state called “microchimerism” may hint at the increased incidence of autoimmune responses in women, and in their children. DNA analysis of postpartum autoimmune disease victims indicates they have increased amounts of their child’s DNA in their system. It may be that, if a child’s histocompatibility genes (“tissue type”) are very different from the mother’s, her immune system cleans the fetal cells out with efficiency. The increased risk may be in the cases where the child is genetically just a little bit different from the mother, confusing the immune system about whether it’s recognizing self or other. And:

Preliminary evidence even suggests that there is such a thing as multigenerational

microchimerism, in which a woman with an autoimmune disorder can blame both

her mother and her children for her misery. In these bizarre instances, the woman

harbors circulating cells from her mother and from her offspring that turn out to

be more compatible in their HLA palette with each other than either is with the

mother in the middle.

Theoreticians also suspect a role for the reproductive hormones, given the correlation of risk with the childbearing years and the effects of the changing hormonal environment of pregnancy — sometimes ameliorating, sometimes exacerbating — on various autoimmune diseases. But hormonal treatments are not entered into lightly. Another exciting study succeeded in curing mice of Type I diabetes (the autoimmune kind) by injecting a substance that programmed the white blood cells involved in the immune response for cell death. My question: what happened to the mouse’s immune defenses after a treatment of such ferocity? New York Times