Immune Profile and Body Composition of Independent Oldest Old: The Longevous Project

Abstract

Introduction: Immunosenescence is associated with changes in lymphocyte function, thymus atrophy, and a chronic inflammatory process referred to as “inflammaging,” which may in part be linked to eating disorders. Objective: The aim of the study was to determine the prevalence rate of immunological alterations, including immune risk profile (IRP), and their association with body composition in the oldest old individuals. Methods: A cross-sectional study of 201 older adults aged 80 years and over, able to walk unaided, with no cognitive or immunological impairment, and with no serious diseases was conducted. Blood samples were collected between 2012 and 2014 during the morning period, and the following tests were conducted: urea, creatinine, hemogram, fasting glucose, glycated hemoglobin, transferrin, albumin, 25-OH vitamin D, and high-sensitivity CRP. Plasma cytokines were measured and mononuclear cell counts were performed by flow cytometry. Anthropometric measurements and densitometry using dual-energy X-ray absorptiometry (DXA) were performed to assess body composition. Results: Mean age was 84.4 ± 3.7 years, and the numbers of T cells were CD4, 784.0 cell/µL; CD8, 371.0 cell/µL; and CD4/CD8, 2.4. The rate of CD4/CD8 <1 (IRP) was 9.4%, CD4/CD8 1–5 was 85.6%, while CD4/CD8 >5 was only 5.5%. CRP, tumor necrosis factor, IL1, IL4, IL6, and IL10 variables showed a high coefficient of variation but low mean values of 1.1 ± 3.1 mg/L for CRP (reference range <3 mg/L) and 3.9 ± 5.0 pg/mL for IL6 (reference range <7.0 pg/mL). The same pattern was found for all other inflammatory variables assessed, characterizing a population whose values indicated low level of inflammation, considering age. Lean mass, as measured by DXA, was higher in men than in women, while the inverse was found for fat % (p < 0.001). A positive association between CRP values and DXA fat % (p value: 0.007, r: 0.49) and a negative association between CRP values and DXA lean mass (p value: 0.046, r:–0.37) was observed. Conclusion: In the independent oldest old, IRP rate proved low and high-sensitivity CRP was shown to be associated with body composition.