Circulating immune complexes of Abeta and IgM in plasma of patients with Alzheimer's disease.
It has previously been shown that immune complexes (IC) of a given biomarker with class M immunoglobulins (IgM) provide better performances compared to the unbound biomarker in a number of cancer entities. In the present work, we investigated IC of IgM-Abeta as a potential biomarker for Alzheimer's disease (AD). Abeta-IgM concentration has been measured in 75 plasma samples from patients with AD, individuals with mild cognitive impairment (MCI), and healthy age- and sex-matched controls (HC). To characterize the fractions associated with Abeta, pooled plasma samples were subjected to gel-filtration analysis. Size-separated fractions were analyzed for the presence of Abeta using a sandwich ELISA assay. A strong reactivity was observed in the high molecular weight IgM (>500 kDa) and 150 kDa (IgG) fractions indicating that blood Abeta is strongly associated with antibodies. Using an ELISA assay detecting Abeta-IgM complexes, we observed that high levels of Abeta-IgMs were detectable in HC and MCI patients; however, there was no significant difference to the AD group.
Marcello
Andrea
A
Department of Psychiatry, University Medicine Goettingen, Göttingen 37075, Germany.
Wirths
Oliver
O
Schneider-Axmann
Thomas
T
Degerman-Gunnarsson
Malin
M
Lannfelt
Lars
L
Bayer
Thomas A
TA
D000368:Aged; D000544:Alzheimer Disease / Q000097:blood* / Q000276:immunology* / Q000503:physiopathology; D016229:Amyloid beta-Peptides / Q000032:analysis / Q000097:blood* / Q000276:immunology*; D000936:Antigen-Antibody Complex / Q000032:analysis / Q000097:blood*; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D001921:Brain / Q000276:immunology / Q000378:metabolism / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
D016229:Amyloid beta-Peptides; D000936:Antigen-Antibody Complex; D015415:Biomarkers; D007075:Immunoglobulin M