Fig. 4: Putative RA-associated HLA-DR peptide-binding cores primarily consist of native sequences enriched by citrullination.

a–c Log2 enrichment of putative binding cores (<500 nM) predicted by the NetMHCII-2.3 algorithm, denoted by the first three amino acids of the peptide core. Cores with positive values are enriched in the PAD2- or PAD4-citrullinated (cit) samples, while those with negative values are reduced by citrullination. *Denotes a uniquely created or destroyed peptide, and color-coded cores are those that contained a citrullination site. d Pie charts representing the proportion of all putative binding cores belonging to several categories (given by legend) denoting the behavior of each core in response to citrullination.