Better satisfaction with life is associated with normal immune profile (CD4/CD8 ratio) – and dependent on the successful aging status – in older Brazilian individuals

Introduction: The immune system is an important determinant of longevity and has also contributed to the way individuals feel as they reach older ages. The inverted CD4/CD8 ratio is a parameter of the immune risk phenotype, and its prevalence increases with age. Association between immunological function, cognition and mood has been supported by studies with clinical and aging populations. Objective: We explored the relationship between the CD4/CD8 ratio and life satisfaction in a small sample of elderly people from Southern Brazil with good general health. Method: The sample consisted of 44 elderly individuals, who participated in an aging study in Southern Brazil (the PALA Study), and accepted to continue in the investigation collecting additional blood sample for the CD4/CD8 analysis. From this sample, 52% (N = 23) presented successful aging according to Rowe and Kahn’s criteria. No participant was HIV positive or presented any autoimmune diseases. A questionnaire was applied for sociodemographic and clinical data, lifestyle, and occupational activity. Cognitive function, basic and instrumental activities of daily living, and depressive symptoms were evaluated with specific instruments. Life satisfaction was evaluated with the Life Satisfaction Scale from Diener et al. (1985). Results: Forty-two individuals (95%) showed CD4/CD8 ratio>1. CD4/CD8 ratio correlated significantly with life satisfaction (rho = -0.35) and with age (rho = -0.42) for the whole sample and among the successful aging sub-group only. Conclusion: This is an exploratory analysis with a small sample of elderly participants from a cohort started in 1996 in Southern Brazil (the PALA study). Their level of satisfaction with life was high, and correlated significantly, and inversely, with the CD4/CD8 ratio. It was also dependent on the successful aging status