Abstract
An aging-related immune phenotype (ARIP) has been defined as a decrease in naïve T cells (T(N)) relative to the accumulation of memory T cells (T(M)). Recent research implicates ARIP measures, such as CD4 +T(N)/T(M) and CD8 +T(N)/T(M) ratios, in multimorbidity and mortality. This study examined whether psychological dispositions that assess how people think, feel, and behave are related to CD4 +T(N)/T(M) and CD8 +T(N)/T(M). Participants were adults aged 50-104 years (N = 4798; 58% women, Mean Age= 67.95, SD= 9.56) from the Health and Retirement Study. Data on CD4 +T(N)/T(M) and CD8 +T(N)/T(M) were obtained in 2016. Data on personality, demographic factors, and potential clinical (body mass index, disease burden), behavioral (smoking, alcohol, physical activity), psychological (depressive symptoms, stress), and biological (cytomegalovirus IgG antibodies) mediating factors were obtained in 2014/2016. Controlling for demographic factors, higher conscientiousness was related to higher CD4 +T(N)/T(M) and CD8 +T(N)/T(M). To a lesser extent, higher neuroticism and lower extraversion were associated with lower CD4 +T(N)/T(M.) Physical activity, and to a lesser extent BMI and disease burden, were the most robust mediators between personality and ARIP measures. Cytomegalovirus IgG level mediated the association between conscientiousness and both CD4 +T(N)/T(M) and CD8 +T(N)/T(M). This study provides novel evidence that personality is related to ARIP. Higher conscientiousness and, to a lesser extent, higher extraversion may be protective against age-related immunophenotype change, whereas neuroticism may be a risk factor.