Increased serum neopterin concentrations in patients with Alzheimer's disease

We measured serum neopterin concentrations in 24 patients with Alzheimer's disease (8 males, 16 females; age: 73.1 +/- 6.2 years; free of any infectio us process) and fourteen controls of similar age (4 males, 10 females; age: 69.7 +/- 8.8 years). Compared to controls, significantly higher concentrat ions of neopterin (p < 0.01) were found in patients with Alzheimer's diseas e. Among patients, concentrations of neopterin were higher in those with lo wer mini-mental-state (p < 0.05), and an invers correlation existed between mini-mental-state and neopterin concentrations. No such association existe d with the duration of the disease. There were also significant correlation s between neopterin and serum concentrations of immune activation markers s uch as soluble tumor necrosis factor (TNF) receptor and soluble interleukin -2 receptor (all p < 0.01). Thus, increased concentrations of neopterin in serum of patients with Alzheimer's disease correlate with the severity of d ementia. The data imply a chronic state of peripheral immune activation in Alzheimer's disease.