CHRONIC CAREGIVING STRESS ALTERS PERIPHERAL-BLOOD IMMUNE PARAMETERS -THE ROLE OF AGE AND SEVERITY OF STRESS

Background: To examine the impact of chronic psychological stress on t he immune system, a series of cellular and humoral immunological param eters was compared in 18 female caregivers of handicapped people and 1 8 age- and sexmatched controls. Methods: The immunological parameters included assessment of T cell number (T cells, T helper, and T suppres sor/cytotoxic) and function (delayed-type cutaneous hypersensitivity), antibody titers for latent herpesviruses (cytomegalovirus and herpes simplex virus 1 and 2), and markers of inflammation (complement C3 and C4 factors and c-reactive protein). Serum immunoglobulins (IgG, IgM, IgA, IgE) and titers for the nonlatent virus roseola were used to cont rol for nonspecific elevations in serum proteins. Results were associa ted with the age of the investigated subjects, the severity of stress (family burden) and the degree of disability of the handicapped people . Results: Caregivers had a significantly lower percentage of T cells, a significantly higher percentage of T suppressor/cytotoxic cells and a significantly lower T helper:suppressor ratio. Subjects were also a nalyzed after division into two groups according to the median age (45 years). Compared to their matched controls, older caregivers (mean ag e = 50.3) also had lower numbers of T cells and T helper cells and hig her antibody titers for cytomegalovirus. In addition, in the caregiver population severity of stress was significantly positively correlated with T suppressor/cytotoxic cells and negatively correlated with T he lper:suppressor ratio. No other differences in the immune parameters w ere found between caregivers and controls. Conclusions: The results in dicate that psychological stress differentially affects various aspect s of the immune system and confirm the relevant role of age and severi ty of stress in modulating these influences.