Circulating immune complexes in sera from patients with Alzheimer's disease and subjects with age-associated memory impairment

Abstract

Before, we reported a higher frequency of circulating immune complexes (CIC) in the sera from institutionalized Alzheimer's disease (AD), multi-infarct dementia and Down's syndrome patients than from age-matched controls. In this study, we tested the presence of CIC in the sera from an extended series of hospitalized AD patients, AD patients living in the community, from age-associated memory impairment (AAMI) subjects as well as from nursing home and community controls. We used two methods to measure CIC, C1q binding Elisa (C1qB-Elisa) and conglutinin binding (KgB-Elisa). The AD patients showed the highest frequency of positive findings and differed from the controls in KgB (42% vs. 17%) (Chi-square, p = 0.01) and C1qB (30% vs. 11%) (p < 0.05). In severe AD, 14/19 patients were KgB positive and 11/19 were C1qB positive and differed from controls. The frequency of CIC for the patients with moderate or mild dementia, the AAMI subjects and controls was similar. In the multivariate linear regression analysis, high CIC values of the AD patients significantly associated with a long disease duration and a history of recurrent urinary infections but not with age, sex, hospitalization, or the Mini-Mental Status score. We conclude that AD patients with severe dementia frequently show CIC but those with mild or moderate disease do not. The CIC relate to a long disease duration and a history of recurrent urinary infections.

Erythrocyte Sedimentation Rate in Alzheimer's Dementia

“…Investigators report elevated levels of tissue necrosis factor in AD sera compared with sera of nondemented controls 3 . Moreover, AD patients with severe dementia frequently demonstrate elevated circulating immune complexes not seen in patients with mild or moderate disease 4 …”

Age‐Associated Memory Impairment and Alzheimer's Disease

“…Morris and McManus 6 concluded that neurological signs are poor differentiators between healthy older people and those with early disease. CT, 12 MRI, 13 electrophysiological, 14 and clinical laboratory 15 measures have not clearly differentiated AAMI from early AD or other dementia. Whether neuropathology distinguishes AAMI from AD or other dementias is also partly a matter of definition.…”

Infectious agents and age-related neurodegenerative disorders

“…Infections in the elderly can result in cognitive impairment that outlasts the infection; in patients with AD who encounter a systemic infection, cognitive function can be impaired for several months after the resolution of a systemic infection and the cognitive impairment is preceded by raised serum levels of interleukin 1 beta (Holmes et al, 2003). Soininen et al (1993) analyzed circulating immune complexes in the blood of patients with AD and individuals with age-associated memory impairment. AD patients with severe dementia had significantly elevated levels of circulating immune complexes compared with AD patients with mild or moderate disease and to control subjects and individuals with age-associated memory impairment.…”