About 30 percent of women successfully treated for breast cancer suffer persistent fatigue of unknown origin. Earlier studies have found elevated levels of several inflammatory markers in circulating blood among breast cancer survivors experiencing fatigue.
To identify the immunologic basis for these elevations, Julienne E. Bower, a researcher at UCLA's Jonsson Cancer Center and an assistant professor at the UCLA Neuropsychiatric Institute's Cousins Center for Psychoneuroimmunology, and colleagues examined cellular immune system status in 20 fatigued breast cancer survivors and 19 matched non-fatigued breast cancer survivors.
Fatigued survivors, compared with non-fatigued survivors, had statistically significantly increased numbers of circulating T lymphocytes, with pronounced elevation in the numbers of CD4+ T lymphocytes and CD56+ effector T lymphocytes.
These changes were independent of patient demographic and treatment characteristics. The increased numbers of circulating T cells correlated with elevations in the level of serum interleukin 1 receptor antagonist (a marker of inflammation). The authors note that these results require confirmation in a larger study.