Lay Summary

Proposal No.  IBD-0153R2
Principal Investigator:  David L. Suskind, M.D.
Applicant Organization:  Children's Hospital and Regional Medical Center (Seattle, Washington, U.S.A.)
Project Title:  Maternal microchimerism in inflammatory bowel disease
Period of Award:  October 1, 2005 – September 30, 2007

Inflammatory bowel disease (IBD) shares many similarities with another disease affecting the gastrointestinal tract called graft verses host disease (GVHD).  GVHD occurs after bone marrow transplantation by the transfer of alloimmune cells, or cells that differ genetically from an individuals own immune cells.  These alloimmune cells can cause inflammation in the intestines that is similar to the inflammation seen in IBD.

Microchimerism occurs when cells from one individual transfers to another, as seen in bone marrow transplantation.  The transfer of maternal white bloods cells can also occur during normal pregnancy, starting as early as the tenth week of gestation and continuing up to delivery.

This study will determine if the transfer of maternal cells to her offspring (‘maternal microchimerism’) leads to inflammatory bowel disease.

We hypothesize that patients with IBD have maternal microchimerism in both blood and tissue and that microchimerism leads to alloimmune type disease similar to GVHD.  We will examine blood and tissue samples of patients with IBD for evidence of maternal microchimerism.  We will also examine how the patient’s immune system responds to being challenged with maternal cells.  Normally, maternal cells are rejected as foreign by an offspring’s immune cells.  We will test if this response is normal in patients with IBD.  Any diminution or enhancement of the immune response would support findings of maternal microchimerism and could identify the role of the immune system in the onset of IBD.

This study aims to determine a potential etiology or mechanism for IBD.  If an etiology or mechanism were determined, the impact on disease diagnosis, management, treatment and prevention would be enormous.  New drug therapies, including targeting maternal cells, could emerge.