Avidity of antineurocytoskeletal antibodies in Alzheimer's disease patients.

AIMS To optimise the ELISA method for the avidity of IgG antibodies against neurofilament heavy chain (NfH) and to determine the levels and avidity of anti-NfH antibodies in patients with Alzheimer's disease (AD) and a healthy control group. METHODS Various dilutions of sera and concentrations of urea and sodium chloride as chaotropic reagents were tested in the process of the ELISA optimisation. The levels and avidity of anti-NfH antibodies were determined in 30 patients with Alzheimer's disease and 30 age-matched cognitively normal elderly adults. RESULTS Sera dilution 1:200 and urea as a chaotrope in a concentration 6 mol/L were chosen to be the most suitable for the avidity assay of anti-NfH antibodies by ELISA. The results showed no differences in either level or avidity of IgG anti-NfH antibodies between AD patients and cognitively normal persons. The levels of anti-NfH IgG antibodies inversely correlated with their avidities. CONCLUSIONS We optimised the ELISA method for the determination of anti-NfH antibody avidity determination which is suitable for research of anti-NfH antibody avidity in patients with neurological diseases associated with neurocytoskeletal defects. The determination of serum anti-NfH antibody avidity in AD patients seems to have limited diagnostic significance.