Chronic Lymphocytic Leukemia (CLL)

Background of Chronic Lymphocytic Leukemia (CLL)

Chronic lymphocytic leukemia (CLL) is a condition characterized by an accumulation of abnormal white blood cells or lymphocytes in the blood and the bone marrow. These lymphocytes cannot perform their normal infection-fighting functions and interfere with the production of other blood cells, leading to multiple complications including immune deficiency, bleeding, swollen lymph nodes and other conditions.

[ Back to Top ]

Who is at Risk for CLL?

About 15,000 new cases of chronic lymphocytic leukemia (CLL) are expected to be diagnosed in the United States this year. It is the second most common type of leukemia in adults. More than half of people diagnosed with CLL are older than 70, and cases rarely occur in individuals younger than 40. There are no known lifestyle risk factors and there are very few factors in the environment linked to CLL. However, some studies have indicated that herbicides and insecticides used in farming and Agent Orange are linked to the disease. Having a first degree relative like a parent, sibling, or child with CLL is the only known inherited risk factor.

Most people show no symptoms at the time of diagnosis, and usually the cancer is found while conducting a blood test for an unrelated reason.

Hutchinson Center CLL Research

Overview of Hutchinson Center CLL Research

Bone-marrow and stem-cell transplantation procedures developed at the Hutchinson Center are largely responsible for boosting the five-year survival rates for chronic lymphocytic leukemia (CLL) from 14 percent in the 1960s to nearly 75 percent today. Now, center researchers are developing less toxic transplant procedures that can extend this lifesaving treatment to older patients, who make up the largest proportion of CLL cases.

A major research focus of this effort is the development of stem-cell transplants that do not require that the patient's marrow be destroyed with high-dose radiation and chemotherapy prior to infusion of donor cells. The technique, called nonmyeloablative transplant, is often referred to as a "mini-transplant" and involves minimal radiation and substantially reduced side effects. It can often be performed completely in an outpatient clinic.

Hutchinson Center researchers are also pursuing a variety of approaches aimed at harnessing the body's immune response to fight the cancer. These include cancer-killing T-cells, anti-cancer vaccines and an array of antibody-based treatments that specifically target cancer cells.

[ Back to Top ]

Extending transplant therapies to more patients

The primary goal of Dr. Brenda Sandmaier's research is to develop less toxic pretransplant regimens that can extend the benefits of stem-cell transplants to more people suffering from leukemia, ovarian cancer or myelodysplastic syndromes.

In laboratory experiments, Sandmaier's team is taking a two-pronged approach to investigating the use of engineered immune system proteins called monoclonal antibodies. Monoclonal antibodies target specific proteins displayed on the surface of select cells. In one line of research, the team is targeting specific immune-system cells, called CD3/TCR, to suppress undesirable interactions between donor stem cells and the patient's immune system. The objective is to establish a tolerance of the two immune systems, called mixed chimerism, which will allow later infusion of donor T-cells that recognize the abnormal cells in the patient's system and eliminate them while sparing the patient's normal cells.

Monoclonal antibodies target specific proteins displayed on the surface of select cells. In one line of research the team is targeting specific immune system cells, called CD3/TCR, to suppress the immune system interaction between donor stem cells and the patient's immune system. The objective is to establish a tolerance of the two immune systems, called mixed chimerism, which will allow later infusion of donor T-cells that recognize the abnormal cells in the patient's system and eliminate them while sparing the patient's normal cells.

In the second approach, Sandmaier's team is using monoclonal antibodies to carry lethal doses of either chemotherapy or radiation directly to abnormal or malignant cells. The objective is to deliver a more concentrated attack on cancer or other diseased cells to reduce the amount of disease before infusion of cancer-fighting donor stem cells. This approach aims to reduce the chance that the cancer will recur after treatment.

[ Back to Top ]

Mini-transplants offer new hope to patients

Dr. Rainer Storb's clinical research team has successfully developed a radically different approach to bone-marrow transplantation that opens up the possibility of a cure for many more people. Because this new treatment, called the mini-transplant or nonmyeloablative stem-cell transplant, does not wipe out bone marrow, patients experience minimal toxicity. The procedure offers new hope for older or otherwise medically unfit patients who cannot withstand the rigors of a conventional transplant. The mini-transplant involves minimal doses of radiation, meaning that patients do not lose their hair or experience severe nausea or other side effects, and typically can be performed without a hospital stay.

Storb's team initially published results of an international study involving 46 patients with an average age of 56 years who underwent the new procedure. The study demonstrated that the new mini-transplant might offer hope to more patients with leukemia and nonmalignant blood disorders than ever before. Two-thirds of the study participants — patients who previously would have had little chance of a cure — had survived more than a year.

To date, hundreds of patients have received mini-transplants at Fred Hutchinson and more than a dozen other institutions. The procedure eventually may be offered to a wide range of patients, offering an easier, lower-cost therapy for people with leukemia, myeloma, lymphoma, sickle-cell anemia and autoimmune diseases.

Storb and colleagues are now exploring the potential of the mini-transplant to treat solid tumors, such as kidney cancer.

[ Back to Top ]

Articles Related to Chronic Lymphocytic Leukemia (CLL) and CLL Information

• Gaining gastrointestinal GVHD control
  
  
• A grateful gathering
  
  
• Nothing small about mini-transplants
  
  
• Full recovery after cell transplantation for treating leukemia or lymphoma can take 3-5 years
  
  

Search for More Publications Related to CLL and CLL Information »