Effect of mild acute stress on immune cell distribution and natural killer cell activity in breast cancer patients

The present study explored cardiovascular and immune responses to a standardized laboratory challenge (speech task) in 23 breast cancer patients. All patients were diagnosed with positive axilliary lymph nodes and received tamoxifen as an adjuvant treatment throughout the course of the study. As a control group, 15 age-matched healthy women were included. At baseline, there were no differences in blood pressure and heart rate values between breast cancer patients and healthy women. With respect to the lymphocyte subsets at baseline, patients had significantly higher absolute numbers of CD16/56 (NK) cells. We speculate that the increase in circulating NK cells can be either a sign of activation of aspecific natural immunity caused by tumor cells or an immunostimulatory effect of tamoxifen. No differences were found in total lymphocyte count and numbers of CD3, CD4, CD8 or CD19 (B) cells. The pattern of changes induced by the speech task with regard to number and function of peripheral immune cells confirm earlier findings derived from healthy subjects. Overall, marked increases were observed in NK and CD8 cells, whereas smaller changes were observed in numbers of CD4 and CD19 (B) cells in response to the speech task. There were no significant differences in the acute stress-induced immune cell changes between breast cancer patients and healthy women. These results seem to implicate that the distribution of immune cells is intact in patients with localized breast disease. With respect to natural killer cell activity (NKCA), our results, as do those of others, show a significant increase in response to the speech task in both healthy women and patients. Compared to the NKCA responses of healthy women, those of breast cancer patients appeared to be delayed. Potential mechanisms behind this difference are discussed. (C) 1998 Elsevier Science B.V. All rights reserved.