Pattern of epitopic reactivity of the anti-Hu antibody on HuD with and without paraneoplastic syndrome

摘要

Previous study has shown that the anti-Hu antibody titre ofserum samples from patients with paraneoplasticencephalomyelitis/paraneoplastic sensory neuronopathy (PEM/PSN) wassignificantly higher than that from patients with small cell lungcancer without neurological disturbances (non-PEM/PSN). The aims ofthis study were (1) to identify the fine epitopes on HuD recognised bythe anti-Hu antibody, (2) to determine if the pattern of epitopicreactivity differed between antibodies from patients with and withoutPEM/PSN, and (3) to determine if the pattern of epitopic reactivitycorrelated with the clinical features. Recombinant full length HuD andnine deletion fragments were constructed and immunoreacted by western blot analysis with 14 anti-Hu serum samples from eight patients withPEM/PSN and six without PEM/PSN. All anti-Hu serum samples reacted withthe deletion fragments containing amino acids (aa) 90-101 or aa171-206. Some anti-Hu samples reacted with the deletion fragmentscontaining aa 223-234, aa 235-252, or aa 354-373. There was nodifference in the pattern of epitopic reactivity between patients withand without PEM/PSN. There was no correlation between the pattern ofepitopic reactivity and the clinical features. The anti-Hu antibodytitre from patients with PEM/PSN was significantly higher than frompatients without PEM/PSN, but there was overlap of their titreconcentrations. In conclusion, aa 90-101 and aa 171-206 are the majorepitopes with which all anti-Hu serum samples react, and aa 223-234,aa 235-252, and aa 354-373 are the minor epitopes with which onlysome anti-Hu serum samples react. The analyses suggested that thepattern of epitopic reactivity of the anti-Hu antibody on HuD was not acritical factor for the development or clinical features of PEM/PSN.