Immune senescence and cancer in elderly patients: Results from an exploratory study

Background: The challenge of immune senescence has never been addressed in elderly cancer patients. This study compares the thymic output and peripheral blood telomere length in >= 70 year old cancer patients. Patients and methods: Fifty-two elderly cancer patients and 39 age-matched controls without personal history of cancer were enrolled. All patients underwent a Comprehensive Geriatric Assessment (CGA), from which a multidimensional prognostic index (MPI) score was calculated. Peripheral blood samples were studied for nave and recent thymic emigrant (RTE) CD4(+) and CD8(+) cells by flow cytometry. T-cell receptor rearrangement excision circle (TREC) levels, telomere length and telomerase activity in peripheral blood cells were quantified by real-time PCR. Results: The percentages of CD8+ nave and CD8(+) RTE cells and TREC levels were significantly lower in cancer patients than in controls (p=0.003, p=0.004, p=0.031, respectively). Telomere lengths in peripheral blood cells were significantly shorter in cancer patients than in controls (p=0.046) and did not correlate with age in patients, whereas it did in controls (r=-0.354, p=0.031). Short telomere (<= median)/low TREC (<= median) profile was associated with higher risk of cancer (OR=3.68 [95% CI 1.22-11.11]; p=0.021). Neither unfitness on CGA nor MPI score were significantly related to thymic output or telomere length in either group. Conclusions: Immune senescence is significantly worse in elderly cancer patients than in age-matched controls. The low thymic output and the shorter telomeres in peripheral blood cells of cancer patients may reflect a pre-existing condition which facilitates the onset of malignancies in elderly people. (C) 2013 The Authors. Published by Elsevier Inc. All rights reserved.