Discoveries
Research yields insights into patients' infection resistance
Nicholas Haining, BM, BCh, is focusing on the immune response.
One of the longest-standing puzzles about cancer treatment is why, despite a sharp drop in the number of disease-fighting T cells, relatively few people receiving cancer chemotherapy die of infection. A recent study by pediatric oncology researchers at Dana-Farber and Children's Hospital Boston offers an explanation.
Investigators led by Nicholas Haining, BM, BCh, measured the number of T cells, the production of new T cells by the thymus gland, and the proportion of T cells that retained a "memory" of earlier infections in two sets of children: those undergoing a two-year chemotherapy regimen for acute lymphoblastic leukemia (ALL), and a similarly aged, healthy group.
As expected, they found that most of the ALL patients had severe T cell shortages at the time of diagnosis and during treatment. Also, as expected, they found that production of new T cells was significantly down in these children, as was the proportion of "naïve" T cells, which had not yet been programmed to fight specific infections.
When the researchers measured the levels of memory T cells (which are already trained to recognize infectious agents), however, they found them to be surprisingly strong. "This relative sparing of T cell memory may, in part, explain why patients treated for ALL retain a protective immunity against infection," Haining states.
According to the study authors, the findings suggest that efforts to strengthen the immune defenses of cancer patients are most likely to be successful if they concentrate on expanding the pre-existing supply of memory T cells.
