T-CELL INTERFERON-GAMMA BINDING IN PATIENTS WITH DEMENTIA OF THE ALZHEIMER-TYPE

Objective: To study T-cell-dependent immune function in patients with dementia of the Alzheimer type (DAT). Design: Assay interferon gamma b inding on T lymphocytes in patients with DAT, as compared with healthy controls. Setting: The study was performed on ambulatory patients in a tertiary care center, where patients were diagnosed as having DAT ac cording to the National Institute of Neurological Disorders and Stroke criteria. Patients: Thirty-five nondepressed patients with DAT (15 wo men and 20 men; mean [+/-SD] age, 68.6+/-15.8 years) were selected con secutively. They were drug free for at least 3 weeks and did not smoke . Illness severity was evaluated according to the Clinical Dementia Ra ting Scale. The control group comprised 35 age- and sex-matched, healt hy, nonsmoking subjects; with no family history of neuropsychiatric di sorders. Results: A significant reduction (P<.001) of T-lymphocyte int erferon gamma binding was observed in patients with DAT as compared wi th healthy controls (611+/-19 [SE] vs 702+/-11 [SE] receptors per cell , respectively), whereas the dissociation constant (ligand-receptor af finity) values were similar in the 2 groups (1.1+/-0.06 [SE] and 1.2+/ -0.06 [SE] nmol/L). Conclusion: These data demonstrate a derangement o f the immune response in patients with DAT, since cell surface interfe ron gamma receptors seem to be related with T-lymphocyte immune functi on.