Washington: Recent studies indicate that genetic blood disorders can be treated with gene therapy, giving hope to millions of thalassemic patients worlwide. Applicable to patients with beta-thalassemia and other inherited blood disorders, scientists transplanted beta-thalassemic mice with stem cells treated with MGMT (methylguanine methyltransferase) and imparted a chemotherapy drug to the mice.

The study published in the July issue of journal Blood reported that the drug particularly increased the normal or globin-expressing cells to levels that diminished, or in some cases cured the disease. Subsequenlty, the transplanted donor stem cells reversed the beta-thalassemia in the mice as the drug- resistant cells assumed production of normal red blood cells in the bone marrow,

"Our finding gives us hope that we might one day be able to help patients with hemoglobin diseases generate healthy blood cells in their own bodies," said Derek Persons, assistant member in the St. Jude Department of Hematology/Oncology, Memphis and lead author of the paper.

Hopeful of the findings, Derek feels that the technique will enable enriching the population of cells carrying the normal gene by eliminating competing, defective cells, without using radiation or intensive chemotherapy.

Researchers used an oncoretrovirus to transfer MGMT into normal bone marrow cells and the treated cells were then transplanted into beta-thalassemic mice previously given non-myeloablative (non-life-threatening) pre-transplant conditioning. Following treatment, the mice showed persistent improvement of their blood, suggesting that the modified stem cells assumed the production of red blood cells after the treatment eliminated the defective stem cells.

"Currently, we are unable to transplant an adequate number of genetically altered bone marrow cells into humans to result in successful treatment of these diseases. We believe that further animal studies will ultimately determine the feasibility of using the MGMT selection process as a treatment," said Dr Persons.

Patients with a major form of thalassemia receive red blood cell transfusions every two to three weeks, which translates to as many as 52 pints of blood a year. However, the high number of red blood cell transfusions these patients receive can lead to iron overload which, if left untreated, may result in early death from organ failure.

Alternatively, some patients may undergo bone marrow transplantation with cells from a matched normal donor. However, this treatment is not available for all patients and entails significant risk. Therefore, new treatment approaches are needed.

ANI