Enhanced viral inhibition of lymphocyte mitogenesis in patients with advanced breast cancer.

Virus particles are frequently able to non-specifically inhibit the capacity of human peripheral blood lymphocytes to respond to mitogenic or antigenic stimuli. In the case of breast cancer patients with advanced disease, the quantity of virus required to abrogate responsiveness to phytohaemagglutinin (PHA) was approximately four-fold less than that found when cells from healthy donors were employed. The results show that such virus co-incubated cultures are deficient with regard to their ability to synthesize detectable quantities of T cell growth factor (TCGF) activity, and that the extent of responsiveness to PHA in each case corresponds roughly to the amount of TCGF activity that is present in the cultures. While the addition of exogenous purified TCGF to cultures containing virus, normal cells and stimulus caused a reversal of the usual inhibitory effect, this finding was generally not obtained in the case of lymphocytes obtained from patients with advanced breast cancer. These data suggest that one mechanism of explaining diminished cellular immune responsiveness in breast cancer patients may be a relative inability of appropriate cells or subsets of cells to respond effectively to TCGF.