Patients with common form of leukemia , having a high level of enzyme indoleamine 2,3 dioxygenase (IDO), which suppresses the immune system, more likely to die early.
According to the Nature Journal Scientific Reports, together with standard therapy, patients can take an inhibitor of this enzyme. "We want to help people who do not respond to treatment and die soon after diagnosis," - says Dr. Ravindra Cole.
The study of 40 patients with acute myeloid leukemia showed increased enzyme expression in bone marrow biopsies performed to diagnose the disease. This indicates that the expression of the enzyme should be measured regularly.
It has already begun a clinical study of enzyme inhibitor. "We wanted to explore what makes this disease so aggressive that the initial induction chemotherapy does not work", - says Cole. Although everyone has the gene for this enzyme, namely tumor cells suppress the immune response. In leukemia, a low level of platelets and a high risk of anemia. In fact, the bleeding is the leading cause of death in patients, and bleeding gums are often a first indicator.
In patients who died six months later, there was a high expression of the enzyme. But when the researchers examined other risk factors such as age, anemia, enzyme levels were higher.
Scientists are trying to determine whether high levels of the enzyme affects the resistance to chemotherapy that occurs in patients who did not survive.
The research team, led by oncologist and immunologist David Munnom Andrew Mellor reported in 1998 in the journal Science that during pregnancy the placenta cells isolated cause suppression of the immune system of the mother. They showed that the enzyme locally disables mother immunity by inhibiting the amino acid tryptophan, and necessary for the survival of T-cells involved in the immune response.
Later, the work of researchers has shown that the enzyme helps the tumor to "hide" from the immune response. On the contrary, some transplant patients, have lower rates of new organ rejection. Kole interested enzyme how one explanation for the different results of treatment of patients using the same methods of treatment of the same disease.
According to the American Cancer Society, at the time of diagnosis of leukemia, most patients 45 years or more, and the disease is more common in men than in women. Induction therapy is performed in order of remission, followed by chemotherapy. Some patients undergoing stem cell transplantation procedure.