Welcome to Study of the Week from Patient Worthy. In this segment, we select a study we posted about from the previous week that we think is of particular interest or importance and go more in-depth. In this story we will talk about the details of the study and explain why it’s important, who will be impacted, and more.

If you read our short form research stories and find yourself wanting to learn more, you’ve come to the right place.

This week’s study is…

Relationships between T-lymphocytes and physical function in adults with chronic lymphocytic leukemia: Results from the HEALTH4CLL pilot study

We previously published about this research in a story titled “Study Highlights Benefits of Exercise for Chronic Lymphocytic Leukemia” which can be found here. The study was originally published in the scientific journal European Journal of Haematology. You can read the abstract of the study here. 

This research team was associated with the University of Texas MD Anderson Cancer Center in Houston, Texas.

What Happened?

Prior research has found that exercise can have significant benefits for patients living with cancer. It can improve exercise capacity, counteract fatigue, and improve overall physical wellness and quality of life. However, this study sought to understand if exercise was making changes on a deeper level in patients living with chronic lymphocytic leukemia, the most widespread form of leukemia among adults in the US. The benefits of exercise for cancer patients is well documented; now, the researchers hoped to find out why.

The study followed 24 patients with chronic lymphocytic leukemia that were at least 18 years old and were healthy enough to participate regularly in moderate-to-vigorous aerobic exercise without direct supervision. Patients were monitored for a 16-week period. Patients were following an aerobic-based physical activity intervention program, which included up to 16 combinations of various exercise components based on four different categories.

Outcomes that the scientists focused on included overall physical function and T-cell phenotype. 38% of the patients had received prior treatment and half of them were being treated during the study. During the 16 week period, patients saw numerous benefits, such as:

• Decrease in body weight
• Decrease in fatigue
• Increase leisure time exercise
• Increase in grip strength
• Increased number of reps in the 30-second sit-to-stand test
• Improved self-perception of physical ability

Cell counts and proportions of CD4+ and CD8+ T-cells didn’t change over the duration of the exercise program. In addition, physical functionality and phenotype of T-cells was not affected by whether a patient was receiving other treatment. Changes to the T-cell profile varied depending on the baseline level of function and the physical changes each individual patient saw following the program.

For patients with increased reports of baseline fatigue, a lower CD4:CD8 ratio, along with a greater proportion of CD8+ T-cells, was found. Following the exercise intervention, patients with the greatest increase in physical ability, as measured by the six-minute walk test and number of arm curls, had less PD-1+ CD4+ T-cells. Lower fatigue and increased leisure time exercise was linked to higher CD4:CD8 T-cell ratio. In patients with less fatigue, a decrease in HLA-DR+CD4+ and HLA-DR+PD-1+CD4+ T-cells was found.

Overall, the team concluded that regular exercise was associated with reduced fatigue and increased leisure time physical activity in older adult patients, and these improvements were correlated with improved T-cell ratios and reduced proportion of T-cell types that are associated with poor outcomes.

About Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia is a form of blood cancer which affects lymphocytes, which are a type of white blood cell. The disease may not cause noticeable symptoms in its early stages. This cancer is linked to certain genetic mutations; notable risk factors for this blood cancer include old age, being male, exposure to certain insecticides, exposure to Agent Orange, and family history. Symptoms of chronic lymphocytic leukemia include fever, anemia, swollen lymph nodes, weight loss, and fatigue. It is also possible for this disease to transform into a more aggressive and faster progressing type of blood cancer like Hodgkin’s lymphoma. Treatment for this disease focuses mostly on controlling symptoms, and there is no cure. These treatments may include radiation therapy, chemotherapy, surgery, bone marrow transplant, or biological therapy. As a slow growing cancer, the five-year survival rate is 83 percent. To learn more about chronic lymphocytic leukemia, click here.

Why Does it Matter?

This study gives scientists an understanding of internal mechanisms that are affected by exercise in people living with this form of leukemia and adds to the wealth of data that demonstrates the benefits of exercise for cancer patients. Furthermore, these findings highlight that benefits don’t just run skin deep.

The authors did acknowledge some potential limitations of the study, such as lack of a control group, small sample size, and the use of different physical activity programs among the patients.

“This study demonstrates that a PA intervention utilizing aerobic exercise can increase leisure time PA and decrease fatigue in older adult patients with CLL, and that these changes are correlated to an improved T-cell ratio and reduced proportion of T-cell subsets indicative of poor prognosis.” – Study authors

Future research should focus on more controlled interventions to further evaluate the impact of exercise on the function of immune cells.