Chronic stress associated with spousal casegiving of patients with Alzheimer's dementia is associated with downregulation of B-lymphocyte GH mRNA

Background. It has been demonstrated that growth hormone (GH) is synthesize d and secreted by human peripheral mononuclear cells (PBMC), and the expres sion of GH mRNA can be found throughout the human immune system. Methods. We studied a population of female caregivers of patients with Alzh eimer's dementia (AD) who suffered from the stress of caring for these pati ents. We utilized quantitative RT-PCR to determine GH mRNA levels in T- and B-cell populations from PBMC. Subjects were nine caregivers of AD patients and nine age- and sex-matched controls. Results. In the control group we found a threefold greater GH mRNA expressi on in B cells than in T cells. This finding was consistent with our previou s in situ hybridization observation, suggesting GH mRNA in predominately B- cell areas of immune organs in humans. We also found that the expression of GH, mRNA from total peripheral blood mononuclear cells and B cells in care givers was 50% and 60% respectively less than that in the control group. Conclusions. Because the B-cell population is the source of antibody produc tion, our findings suggest that the decrease in B-cell GH mRNA may contribu te to the poor immune response to influenza virus vaccination that has been reported previously in chronically stressed caregivers.