L.J. Jones (above) is the only child in the U.S. diagnosed with hypereosinophilic syndrome, a form of leukemia. As BET helps spreads awareness about L.J.’s need for a life-saving bone-marrow transplant, we answer some questions you may have about the disease. Click here for more on L.J. and his upcoming appearance on 106 & Park, and to learn how you can sign up for the bone-marrow registry.

What is hypereosinophilic syndrome?

Hypereosinophilic (hy-per-ee-o-sin-o-FILL-ick) syndrome, also known as HES, is a rare blood disease in which the body produces too much of a particular type of blood cell called eosinophils (ee-o-SIN-o-fills). Eosinophils normally help the body fight allergies and certain types of infections.

People with HES can have different symptoms, depending on which parts of the body are affected. These symptoms may include: fatigue, cough, shortness of breath, muscle pain, rashes, or fever.

How common is HES?

HES is very rare. HES usually develops between the ages of 20 and 50; HES rarely occurs in children. Nine out of 10 cases occur in males.

What causes HES?

The origin of the syndrome is unknown. Researchers have found that in some people with HES, two genes combine to form a new gene. This "fusion gene" causes the body to make a protein known as a kinase (KY-nase), which causes some blood cells to multiply.

How does HES affect a person's body?

The excess eosinophils spill out of the blood and gather in the body's tissues and organs. This may cause enlargement and damage to such organs as the liver, spleen, and heart.

How is HES treated?

The most common treatment for HES consists of high doses of steroids (medications in the cortisone family). Other treatments include medications that suppress the immune system, and anticancer therapies.

Is HES fatal?

Prospects for people with HES depend on how severe the disease is, which bodily organs are affected, and the success of treatment. In some cases, HES may be fatal.

Further reading about HES and other rare diseases:

Preserve Our Legacy www.preserveourlegacy.org

American Cancer Society www.cancer.org

American Partnership for Eosinophilic Disorders www.apfed.org

American Society of Hematology www.hematology.org

Leukemia & Lymphoma Society www.leukemia-lymphoma.org

National Cancer Institute www.cancer.gov

National Organization for Rare Disorders www.rarediseases.org

Image:  Courtesy of Brett Melius