What puzzled doctors who thought they were treating these septic patients, however, was that they couldn’t find any bacteria or viruses that could be causing the high fever, enlarged spleen, liver failure and plummeting blood cell counts that are common to both syndromes. And antibiotics were of little help.

Researchers subsequently noticed that this subset of patients had other important differences from septic cases, including high blood levels of iron and an inflammatory marker called soluble interleukin-2 receptor or (sIL-2R).

People with MAS also have large numbers of specialized cells called hemophagocytes (heem-oh-fag-oh-sites), scavenger cells that eat red blood cells and platelets.

Stepping up to Address a Research Gap

After successfully making the diagnosis in Hayley, and saving her life with high doses of immunosuppressing drugs, Dr. Behrens says he looked to see what research was being done on MAS, and found little underway.

Dr. Behrens knew something needed to be done to help speed the diagnosis and treatment of children and adults caught in this life-threatening crisis.

He approached the Arthritis Foundation for help and got it.

“When you’re working on a rare disease and when you’re working on pediatric diseases, it’s very hard to get funding,” Dr. Behrens says. “I was a somewhat junior investigator. To break ground when you’re unproven and trying to study rare diseases is difficult. This would not have happened without the Arthritis Foundation.”

An Investment Brings Answers

In November, at the 2010 annual meeting of the American College of Rheumatology, Dr. Behrens will present several important new findings about the syndrome in one of the meeting’s plenary sessions.

His first announcement is that he’s conducted the first study to develop a true animal model for MAS. Because human cases are few and far between, the only way to learn about rare syndromes like MAS is to recreate them in animals, usually mice. Dr. Behrens says a separate animal model was needed to study the type of MAS doctors see in their rheumatologic patients.

Arthritis Foundation funding has also allowed him to better understand the role of hemophagocyte cells in MAS. Using a special microscope, he was able to collect and observe large numbers of these rare cells by cutting individual hemophagocytes off slides with a laser – a painstaking process called laser dissection – and gathering them in a test tube.