PRTN3 and rheumatoid arthritis: Moreover, when binding affinity of the ‘VCL-DERAA’ peptide to different HLA molecules was examined, it was shown that the peptide was able to bind to all HLA-DQ molecules that are associated with ACPA-positive RA (i.e. HLA-DQ7, -DQ8 and -DQ5) as these molecules are in strong linkage disequilibrium with predisposing HLA-DR molecules.