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 ≥70year 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 naïve 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(+) naïve 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.
Keywords: ADL; Activities of Daily Living; CGA; CIRS-CI; CIRS-SI; CMV; Cancer; Cumulative Illness Rating Scale-Comorbidity Index; Cumulative Illness Rating Scale-Severity Index; Cytomegalovirus; Elderly; GDS; Geriatric Depression Scale; IADL; Immune senescence; Instrumental Activities of Daily Living; MMSE; MNA; MPI; Mini Mental Status Examination; Mini Nutritional Assessment; PBMC; RTE; RU; SPMSQ; Short Portable Mental Status Questionnaire; T-cell receptor rearrangement excision circle; T/S; TREC; Telomerase activity; Telomere length; Thymic output; comprehensive geriatric assessment; multidimensional prognostic index; peripheral blood mononuclear cells; recent thymic emigrant; relative units; telomere/single-copy gene.
© 2013.