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A Promising Weapon in the Fight Against MS

SCIENCE FILE / An exploration of issues and trends
affecting science, medicine and the environment

Early indications are that stem cell transplants, still an experimental treatment for multiple sclerosis, seem to halt the disease's progression and, for some, lessen its severity.

September 07, 2000|JUDY SILBER | SPECIAL TO THE TIMES

Before getting out of bed every morning, David Hassenpflug reaches for a pill--medication he calls "grease for the tin man"--so he can maneuver joints that have stiffened overnight.

Stiffness is typical for multiple sclerosis, a devastating disease that has left the 34-year-old Long Beach native in a wheelchair.

But Hassenpflug is feeling a little better these days. In June he participated in experimental therapy in which physicians attempted to rebuild his immune system using a stem cell transplant.

He's still stiff, but his voice sounds less like he has marbles in his mouth, and a previously constant pain in his legs and hips is gone. He'll probably never walk again, but his doctor said that, with physical therapy, Hassenpflug should gain strength over the next six months.

Early results from about 100 patients worldwide indicate that stem cell transplants--already used for treating cancers such as leukemia and Hodgkin's disease--hold promise for combating MS. Researchers at Northwestern University also recently reported success using the procedure to treat seven patients with systemic lupus erythematosus, another autoimmune disease.

"We think it's very exciting. To use a transplant designed to treat cancer for another disease is very satisfying," said Dr. Stephen Forman, director of the division of hematology and bone marrow transplantation at City of Hope Cancer Center in Duarte.

Stem cell transplants fall far short of a cure. But published and anecdotal reports suggest that the procedure can halt the disease's progression and, for some, lessen its severity.

"Right now, while it's still experimental, it's for patients who have had and failed conventional therapy," said Dr. James Mason, program director for the blood and marrow transplantation program at Scripps Green Hospital in La Jolla.

But in the future, patients could undergo transplants before receiving other therapies and before they become seriously debilitated, he said.

An ailment with no cure, MS affects about one in 1,000 people. Medications such as interferon and copaxone can only slow, not stop, the downward physical spiral plaguing many. And treatments often do little to alleviate a plethora of conditions, from excruciating pain to muscle spasms.

Like leukemia and Hodgkin's disease, MS results from an immune system gone awry. The disease often strikes previously healthy people between ages 20 and 40, when the immune system begins aberrantly attacking a protective covering around neurons called myelin.

The attacks initially occur intermittently, causing temporary disabilities by short-circuiting electrical signals between the brain and the body. Repeated attacks eventually destroy the myelin, bringing some nerve transmission to a halt. Disabilities become permanent and ever-worsening.

Transplants attempt to stop the attacks by getting rid of the immune cells that attack myelin, Forman said.

In the treatment, physicians attempt to destroy the patient's dysfunctional immune system with radiation and/or chemotherapeutic agents. They then inject healthy stem cells previously collected from the patient's bloodstream, enabling him or her to form a new immune system. The hope is that the newly created immune system will be disease-free.

Because the stem cells are the patient's own, immune-suppressing drugs are not necessary and the procedure is safer than using transplants from a donor.

The protocol for stem cell transplants varies. But generally, doctors begin by increasing the number of stem cells in the blood. A growth hormone pushes stem cells from the bone marrow, where they usually reside, into the bloodstream.

A simple blood collection system removes several pints of blood and runs it through a machine, separating the various blood cells by density. The stem cell layer is run over a column that recognizes a protein called CD34 on the stem cells' surface.

To kill off the faulty immune system, patients receive chemotherapy, radiation or a combination of the two. Once the damaging cells are gone, the stem cells are injected into the blood, where they will generate a new immune system.

"Transplants wipe the slate clean," Mason said. By resetting the immune system, doctors hope the therapy will suppress the indiscriminate attacks destroying nerves.

Even in the best-case scenario, the procedure is likely to have limitations, Forman said. It probably won't repair nerves badly damaged by disease. However, so far, transplants appear to stop the immune system attacks and reduce the inflammation around nerves, improving function, he said.

With the disease stabilized and the inflammation reduced, patients' mobility improves, enabling them to work on gaining strength, Mason said. "The muscle tone gets better. The balance gets better," he said.

Though promising, transplants for MS are experimental, emphasized Dr. Richard Burt, director of allogeneic transplants at Northwestern Memorial Hospital in Chicago.

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