The MDS Beacon™

A study reported in the March issue of Leukemia suggests irregular balance of immune cells in myelodysplastic syndromes (MDS) patients may help predict patient response to therapy that suppresses the immune system. The study also finds that younger MDS patients are more responsive to the therapy than older patients.

Researchers at the H. Lee Moffitt Cancer Center in Florida examined blood samples from 76 MDS patients and several healthy patients as a control. Researchers used a technique called flow cytometry to measure the production of cells. Flow cytometry is a test using a bone marrow sample and treatment with fluorescent dyes to mark and identify developing cells.

Based on the data, researchers concluded that the MDS patients had a reduced number of T helper cells, which are important in the activation and direction of other cells of the immune system.

MDS patients are normally characterized by a lower ratio of T helper cells to cytotoxic T cells, which are cells in the immune system that kill tumor cells and cells infected with viruses or other pathogens. The level of cytotoxic T cells was normal among MDS patients when compared to the control group. Thus, researchers determined that the lower ratio is likely due to a reduced number of T helper cells.

The study also investigated patient response to therapy that suppresses the immune system, known as immunosuppressive therapy. This therapy would, in theory, help prevent an autoimmune response, which is when the body attacks itself and proper formation of blood components.

Previous studies by the National Heart, Lung, and Blood Institute have shown clear results that younger MDS patients are more likely than older patients to respond to immunosuppressive therapy using antithymocyte globulin (ATG).

The researchers at the Moffitt Cancer Center sought to examine the immune status of younger MDS patients in comparison to older patients in an effort to explain why age seems to be a factor in response to therapy. Researchers looked at response to immunosuppressive therapy using ATG in 20 MDS patients.

Results showed that patients who responded to the treatment had an even lower ratio of T helper cells to cytotoxic T cells than non-responders. These results suggest a correlation between a low T cell ratio and a good response to immunosuppressive therapy.

“Using the immune markers that we’ve identified as being associated with response to therapy, we may be able to have a better test than age alone for predicting how a patient will respond,” explained Dr. Pearlie Burnette, one of the lead authors of the Moffitt Cancer Center study. “The goal is to understand the disease process in all types of patients so that we might be able to treat patients more effectively.”

Immunosuppressive therapies are rarely offered to MDS patients in the United States because doctors are still unsure about who is appropriate for the treatment. There is concern that using the therapy may actually increase the risk of a patient developing acute myelogenous leukemia, especially when other more proven treatment options are available.

For more information, please see the study abstract on the Leukemia Web Site.