Human stem cell transplants trialled for auto-immune diseases

Human stem cell transplants trialled for auto-immune diseases

Clinical trials in three continents are providing early encouraging signs that a control for people with immune system diseases such as rheumatoid arthritis, might be achievable within the next 10 years.

'Early data suggest that human stem cell transplants may be useful for people with auto-immune diseases who have not responded to other treatments,' Professor Peter Brooks said.

'It may be the case that immune system transplants may become as common in the future as kidney transplants are today.'

Professor Brooks, who is Executive Dean of Health Sciences at The University of Queensland, was speaking at the 9th Asia Pacific League of Association for Rheumatology conference held recently in Beijing.

Stem cells are the master component of blood marrow, the body's factories in which blood cells replenish themselves. In stem cell transplantation, doctors inject patients with a drug that causes the bone marrow to pump stem cells into the blood.

Doctors then remove stem cells from the blood and freeze them. Patients are given a large dose of chemotherapy through their blood and their own stem cells are replaced within 24 hours.

Professor Brooks said blood stem cell transplantation had developed rapidly as a technology over the last decade.

'The technique has improved long-term disease-free survival for patients with lymphoma and leukaemia and has been used in reducing the toxicity and mortality in other situations where high dose chemotherapy might be used,' he said.

'Stem cells can now be collected from the peripheral blood thus negating painful bone marrow collection and it is now considered standard therapy in the majority of haematology/oncology units.'

He said more than 200 rheumatoid arthritis patients in Australia, the United States and Europe had taken part in clinical trials involving human stem cell transplants since 1997. Eight had died, but the rest had shown a marked improvement in their condition.

Professor Brooks said the mortality rate of up to five percent was an acceptable risk, as the disease took five to 15 years off a patient's life.

Rheumatoid arthritis, which affects one in every 100 people, is an auto-immune disease in which the immune system inappropriately attacks joints as if they were made of foreign proteins, eating away at the cartilage and damaging the underlying bone.

Symptoms include pain, swelling of joints, and later deformity and loss of function in hands, knees and other joints.

'Auto-immune diseases such as rheumatoid arthritis, scleroderma and systemic lupus erythematosus affect many people, can cause death and in some cases are resistant to current treatments,' he said.

'Profound immunosuppression can have a significantly beneficial effect on these diseases but bone marrow toxicity remains a major limiting factor in its use. Recent advances in the technology of human stem cell transplantation (HSCT) using the patient's own cells can assist in reducing the mortality of high dose immunosuppression.'

However, Professor Brooks said, stem cell transplants were still an experimental therapy for auto-immune diseases and should not be done by anyone unless they were part of a controlled clinical trial.

A significant number of issues remain to be clarified. These included the development of appropriate trials which compared HSCT to standard therapies.

'This type of therapy should only be contemplated by rheumatologists working closely with bone marrow transplantation units who have experience and a low mortality rate (less than three percent) for HSCT,' he said.

The next logical step was to use stem cell transplants from healthy people, providing new immune systems for people with auto-immune diseases.

This step cannot currently be attempted because there is a high death rate (20 percent) as a result of the body's rejection of the foreign stem cells, compared with the mortality risk of less than five percent using the patient's own cells.

Media: Further information, Professor Peter Brooks, telephone 07 3365 5106.