T Cell Subset Patterns That Predict Resistance to Spontaneous Lymphoma, Mammary Adenocarcinoma, and Fibrosarcoma in Mice

Abstract

Aging leads to changes in the proportion of several T cell subsets in peripheral blood, but it is not yet known whether these changes have prognostic significance for late-life diseases. To examine this question, levels of T cell subsets were measured at 8 and 18 mo of age in the peripheral blood of mice of a genetically heterogeneous stock, and the mice were then subsequently evaluated for life span and for cause of death. The results indicate that mice whose T cell subset patterns look like those of old mice tend to die at earlier ages, regardless of the specific cause of death. At 18 mo, 39% of the variance within the set of seven measured subsets could be combined statistically into a single number, whose correlation with individual subsets suggested that it could be interpreted as an index of immunological aging. T cell subset pattern, as represented by this index, was a predictor of life span in mice dying of lymphoma, fibrosarcoma, mammary adenocarcinoma, or of all other causes considered together. Even as early as 8 mo of age, T cell subset patterns are significant predictors of all three forms of cancer, although at this age the association is stronger in mated female mice than in virgin mice. These results support two controversial hypotheses, which are not mutually exclusive: 1) early immune senescence might predispose to early death from cancer and 2) differences in aging rate, as monitored by tests of immune status, might accelerate or decelerate a wide range of late life neoplastic diseases.