Host Defenses in the Aged: Evaluation of Components of the Inflammatory and Immune Responses

Abstract

Host defenses were evaluated in 70 healthy aged volunteers. Individuals who had diseases or who were taking medication known to affect the inflammatory and immune responses were excluded from the study. Volunteers were followed for 24 months to correlate their state of health with the evaluation of host defenses. Polymorphonuclear leukocyte function and the serum opsonic capacity for Escherichia coli and Staphylococcus aureus were normal. Assays of complement components and activity revealed unexplained elevations in native C3 and properdin, normal concentrations of factor B, normal conversion of C3 by inulin, and normal levels of hemolytic complement. The levels of IgG and IgA did not differ from levels noted in younger controls, but the concentration of IgM was decreased and that of IgE increased. The prevalence of autoantibodies was low. None of the volunteers were anergic, but lymphocyte responses to mitogens were depressed in three-day cultures. The number and percentages of E-rosette-forming cells and cells bearing surface IgD or IgM were normal. No lymphopenia was noted.

Influence of Age on Oxidative Bursts (Chemiluminescence) of Polymorphonuclear Neutrophil Leukocytes

“…In the elderly, studies of different neutrophil functions have yielded confusing and contradictory results [23]: for example, both decreased [24,25] and normal chemotaxes [26] have been described. In the elderly, phagocytosis has not been found to be statistically different from that of young people [27,28], but it was reduced in two other studies [29,30]; likewise, the intracellular killing of microorganisms by neutrophils was either not different [31,32] or reduced in elderly people [24,28].…”

“…Some phagocytic activities have been shown to be impaired in the elderly [12,13], thus leading to their greater susceptibility to infectious agents [14,15] and contributing towards infectioninduced morbidity and mortality.…”

CD4 T cell memory derived from young naive cells functions well into old age, but memory generated from aged naive cells functions poorly

“…However, the ability of the immune system to respond vigorously to vaccination is also impaired with age (1)(2)(3)(4). Although it is generally accepted that immunological memory generated early in life is maintained well into old age (reviewed in refs.…”

Chronic stress alters the immune response to influenza virus vaccine in older adults.

“…The immunological decrements associated with the stress of caregiving are of particular concern because older individuals already have age-related reductions in cellular immune function with important health consequences; respiratory infections such as influenza and pneumonia remain major causes of morbidity and mortality among older adults, and many older individuals do not respond to influenza virus vaccines (or other novel antigens) as efficiently as younger adults (7)(8)(9)(10)(11) All subjects were part of a larger longitudinal project on stress and health in older adults (2,4,5). For this study, we used matched caregiver-control pairs who had all received an influenza vaccination in the previous year, excluding 22 (Fig.…”