Vulnerable caregivers of Alzheimer disease patients have a deficit in beta 2-adrenergic receptor sensitivity and density.

The chronic stress of caregiving may lead to sympathetic nervous system activation and immune suppression. beta(2)-adrenergic receptors are expressed on all immune cells and contribute to the stress-induced loss of immune-cell function. The authors examined the effects of being a spousal caregiver of a patient with Alzheimer disease (AD) on the lymphocyte beta(2)-adrenergic receptor. One hundred and six women and men, spousal caregivers and non-caregivers, participated (mean age: 71.5 years). Caregivers were classified as either vulnerable or non-vulnerable on the basis of the amount of care required by the patient relative to the amount of respite the caregiver received during the previous 6 months. beta(2)-adrenergic receptor sensitivity (cyclic-AMP response to isoproterenol stimulation) and density (radioligand binding) were determined by use of whole lymphocytes. Vulnerable caregivers had reduced beta(2)-adrenergic receptor sensitivity and density when compared with their non-vulnerable counterparts or with non-caregivers. The findings indicate that for more vulnerable caregivers, the stress of caregiving leads to a loss of lymphocyte beta(2)-adrenergic receptors. This finding may be relevant to previous observations of clinically-relevant reduced immunity in highly stressed caregivers of AD patients.