Lymphopenia in primary degenerative dementia.

The central nervous and immune systems share a number of common properties, e.g. neurotransmitter receptors. In contrast to age matched healthy and/or hypertensive controls, the total lymphocyte count in 25 carefully diagnosed and staged patients with primary degenerative dementia were significantly reduced and also correlated with the severity of their dementia. Subjects' age, age of dementia onset, or duration of illness were unrelated. Total leukocyte counts were similar between groups. Nutritional status, ACTH, or plasma cortisol in dementia cohort were also not explanatory of their lymphopenia. These results are potentially significant in light of an immune hypothesis for primary degenerative dementia: Alzheimer's type and/or that population's high concomitant risk of infection.