James Ferrara is the Ruth Heyn Endowed Professor of Pediatrics and Communicable Diseases and is director of the U-M bone marrow transplant program.

When a patient receives a bone marrow transplant from another person, the sometimes months-long wait begins to see whether the transplant will work.

If the transplant isn’t working, often patients will get the tell-tale signs of a rash on their skin, signaling there may be a potentially deadly complication caused by an immune system reaction.

But a rash also could indicate a relatively common allergic reaction to one of the multiple medications the patient ingests daily.

Researchers from the University of Michigan and the Fred Hutchinson Cancer Research Center in Seattle say they’ve developed a blood test to help doctors better figure out whether patients are developing serious complications and better tailor their treatment.

The kind of bone marrow transplant that replaces a person's abnormal stem cells with healthy ones from a donor is often used to treat sickle cell anemia, leukemia, lymphoma, myeloma and other blood diseases.

“When we transplant bone marrow, it’s not just the stem cells that are being transplanted. It’s also the normal immune system of the donor and the original immune system of the recipient is replaced. So we actually need to get the immune system to accept the body of the patient,” said James Ferrara, senior author of the study.

Ferrara is the director of U-M’s bone marrow transplant program and professor of pediatric oncology.

The medications used to help patients who have a severe immune response following the transplant can also further weaken their immune system.

Roughly 50 percent of bone marrow transplant patients receiving marrow from another person develop the immune response that can become "graft-versus-host disease," which attacks the skin, gastrointestinal system and liver.

Sophie Paczesny is a U-M assistant professor in pediatric hematology-oncology.

Roughly half of those patients die from the disease or from the treatments, Ferrara said.

About 80 percent of patients who receive a bone marrow transplant develop a rash.

Typically, physicians have to take a skin biopsy and run a series of complex tests that can take several days and can be inconclusive in determining whether the patient has developed the complication.

By comparing blood samples from both hundreds of bone marrow transplant recipients and subjects who didn't need a transplant, the U-M researchers discovered a single enzyme found in elevated levels in the blood of those patients experiencing an immune system attack. The enzyme also circulates in the blood of the patients, allowing clinicians to perform the blood test.

Researchers found the test could predict not only whether a patient would develop the complication, but also how severe those complications would become, based on the level of enzyme found in the blood sample. The blood test is not a replacement for traditional testing yet, but has the potential to make a big impact on the way bone marrow transplant physicians tailor their treatment.

About 18,000 people recieved bone marrow transplants from another donor in 2005. The development of the test could have far reaching implications for these patients, the researchers said.

"Our work is a good example of research that could translate from bench to the bedside," said Sophie Paczesny, the study's first author and U-M assistant professor in pediatric heatology-oncology.

The work was published online this week in Science Translational Medicine.

Tina Reed covers health and the environment for AnnArbor.com. You can reach her at tinareed@annarbor.com, call her at 734-623-2535 or find her on Twitter @TreedinAA.