PRTN3 and Huntington disease: To determine the role of the selected linear EBNA-2 peptide (no 17) for ACPA detection, we analysed the antibody reactivity of RA sera and HD sera to the citrullinated peptide with a C-terminal labeling using streptavidin capture ELISA and compared the reactivity of the peptide to two currently available assays; the CCPlus from EuroDiagnostica (CCP2 generation) and CCP3.1 from Inova Diagnostics.