Human brain-immune relationships: a PET study.

To study brain-immune relations, we correlated positron emission tomographic (PET) measures of regional cerebral blood flow (rCBF) with immune measures in 10 female volunteers. The natural killer (NK) activity correlated negatively with activity bilaterally in the secondary sensory cortex, whereas the Concanavalin A (Con A) response correlated positively with rCBF bilaterally in secondary visual, motor, and sensory cortices, the thalamus, the putamen, and the left hippocampus. Although representing preliminary data from a small number of subjects, these observations provide further support for the presence of interactions between the brain and the immune system.