By ingesting a non-radioactive and non-toxic compound "heavy water" for 6 weeks, the DNA of newly developed cells in the body of subjects with B-cell chronic lymphocytic leukemia can be labeled and followed by performing routine blood draws at specified time intervals. By using mass spectrometric analysis we can measure how quickly new B-CLL cells are generated in the bone marrow and how quickly they leave the blood, a measure of cell turnover. This will help us to better understand the unique characteristics of this disease process.

By ingesting a non-radioactive and non-toxic compound "heavy water" for 6 weeks, the DNA of newly developed cells in the body of subjects with B-cell chronic lymphocytic leukemia (B-CLL) can be labeled and followed by performing routine blood draws at specified time intervals. By using mass spectrometric analysis we can measure how quickly new B-CLL cells are generated in the bone marrow and how quickly they leave the blood, a measure of cell turnover. This will help us to better understand the unique characteristics of this disease process.

Inclusion Criteria:

• 18 years of age,
• Patients must be willing to contribute the required amount of blood without compromising their well being,
• Participants must be willing to be contacted in the future.

Exclusion Criteria:

• Pregnancy,
• Patients who are known to be anemic, with a hemoglobin < 8,
• Patients who are known to be infected with HIV.

Chronic Lymphocytic Luekemia