Relationship of interleukin-1 beta and beta 2-microglobulin with neuropeptides in cerebrospinal fluid of patients with dementia of the Alzheimer type.

We studied interleukin-1 beta (IL-1 beta), beta 2-microglobulin (beta 2-m), beta-endorphin, substance P, neuropeptide Y and somatostatin concentrations in the cerebrospinal fluid of 13 patients with dementia of the Alzheimer type (DAT), 13 patients with multi-infarct dementia (MID) and 15 age-matched control subjects. Substance P was significantly lower in DAT than in controls (P < 0.05), as well as somatostatin in DAT as compared to both controls (P < 0.01) and MID (P < 0.05), whereas beta 2-m was higher in DAT than in controls (P < 0.01). Neuropeptide Y, beta-endorphin and IL-1 beta showed similar concentrations in the three groups studied. A significantly positive correlation was observed between IL-1 beta and substance P (r = 0.79, P < 0.01) and somatostatin (r = 0.75, P < 0.05) in DAT, which was not observed in MID. In addition, beta 2-m showed a negative correlation with IL-1 beta (r = -0.73, P < 0.05) in DAT, and age correlated negatively with IL-1 beta in controls and MID, but positively in DAT. Therefore, these results support the idea that an altered relationship may exist in Alzheimer's disease between the nervous and immune system.