Aplastic Anemia: A Rare Disease With a Better Prognosis
Advances are prolonging the lives of people with this once-fatal illness
SUNDAY, Feb. 4, 2007 (HealthDay News) -- Aplastic anemia, a disease of the bone marrow, is a rare disorder in the United States. Only three of every 1 million Americans will be diagnosed with the condition this year, the National Marrow Donor Program reports.
Despite that rarity, this once-fatal disease has become far more treatable as physicians have honed in on practices that can prolong life and ease suffering.
And the effects of that research extend far beyond sufferers of aplastic anemia or other related bone marrow diseases. Insights gained from these diseases are also helping scientists learn about more prevalent health problems, such as heart disease or leukemia, researchers say.
Aplastic anemia occurs when bone marrow stops producing enough blood cells, said Katherine Baer, a patient information specialist for the Aplastic Anemia and MDS International Foundation Inc. Only about 1,000 new cases appear each year in the United States.
A related blood disorder, myelodysplastic syndromes, or MDS, occurs when the bone marrow begins producing poorly functioning or immature blood cells. About 20,000 to 30,000 new cases occur each year.
Doctors still aren't certain exactly what causes the diseases' onset, Baer said.
"They do think it can be caused; there are some toxins that may cause it, like benzene," Baer said. "But at least half the cases are of unknown cause." She added that radiation treatments for other diseases are another suspected cause.
The effects of aplastic anemia and MDS vary, depending on the type of blood cells lacking in the body, Baer said.
Red blood cells carry oxygen, and a shortage of those will cause fatigue and shortness of breath. White blood cells fight infection, so when the body lacks those cells, it is more likely to catch infectious diseases. Platelets cause clotting, and without those, people experience nosebleeds, bleeding gums and extended bleeding from cuts.
These diseases used to be killers, fatal within a year, said Dr. Richard Stone, clinical director of the Adult Leukemia Program at Harvard University's Dana-Farber Cancer Institute and an associate professor at Harvard Medical School.
"Now, people can be expected to live a long time in many cases," Stone said. "It's devastating if untreated but quite approachable if treated."
Baer and Stone said that while no breakthrough treatments have been developed, the available therapies are at the point where people can live with the disorders.
Most people with aplastic anemia will require multiple blood transfusions, which relieve symptoms by providing blood cells that the bone marrow isn't producing, Baer said. Symptoms also can be managed with immunosuppressive drugs similar to those used in AIDS treatment. The drugs suppress the activity of immune cells that are damaging bone marrow, helping the marrow recover and generate new blood cells, she said.
Antibiotics can be used to effectively fight off infections that take advantage of the disorder. And for a longer-term therapy -- or for people with severe aplastic anemia -- bone marrow transplantation is an option, but a limited one due to the difficulty involved in finding a matching donor.
Experimental treatments now being tested include growth factor drugs that may help stimulate the bone marrow to produce new blood cells; male hormones that also might boost blood cell production; and peripheral stem cell transplants. In that procedure, stem cells are taken from the blood of a donor, rather than from their own bone marrow, and transplanted into the patient, according to the Mayo Clinic.
"Twenty, 30 years ago, it [aplastic anemia] was fatal," Baer said. "Now, between the different treatments, 70 to 90 percent can live a long life. You have to continue to monitor your blood counts, and you are on some medication long-term."
Since these diseases involve damage to stem cells, research in this area could provide much insight into the potential of stem cells for treating other types of diseases. Stem cells have attracted much research focus due to their potential regenerative powers and ability to transform themselves into a host of different cells.
Bone marrow stem cells are the most primitive cells in the marrow, and from them, all the various types of blood cells are descended. Research also has shown that stem cells from bone marrow can give rise to non-marrow cells, which has led to federal funding to look into their usefulness in treating heart disease.
"It's very important to understand as much as possible about the bone marrow stem cell," Stone said. "What keeps it going, what causes it to become malignant? The more we understand about those things, the more we'll know about potential uses of stem cells."
To learn more, visit the Aplastic Anemia and MDS International Foundation Inc.