Collaborative Hemophilia study

Hemophilia A is a rare genetic bleeding disorder that affects approximately one in 5,000 live male births. It is caused by a missing or abnormal clotting protein, factor VIII, so the disease is also known as factor VIII deficiency. The frequency and intensity of bleeding episodes related to hemophilia A generally correlates with the severity of deficiency of factor VIII.

The most common treatment is factor VIII replacement. While this approach helps a person with hemophilia A to clot, the infusion also can trigger harmful immune responses called inhibitors. This, in turn, can make treatment less effective, with more bleeding and poorer quality of life.

Currently, both risk factors for immune complications and the mechanisms that drive them are not completely understood. These unknowns are the focus of a National Institutes of Health-funded research effort based at the University of Washington School of Medicine.  

A new initiative called Hemophilia A Analytical Cohort Research Program (HARP) will be led by Dr. Jill Johnsen, a UW associate professor of hematology and researcher at Institute for Stem Cell and Regenerative Medicine.

Johnsen and research colleagues will trace the roots of risk for immune complications, starting from the time in the womb. The investigators plan to follow fifty pairs of mothers who have the gene change that leads to factor VIII deficiency and their babies who have severe hemophilia A.

“Through the longitudinal study design, we have the opportunity to watch the human immune system evolve in ways that haven’t been seen before,” Johnsen explained. “We’re going to study the pregnancy, follow each mother through her delivery, and then follow the mother and baby as a bonded pair for the first years of life. We’ll be collecting blood samples and data as the babies live their lives and are treated for hemophilia, all the while tracking who makes an inhibitor that causes the body to react to the FVIII replacement treatment and who does not.”