PRTN3 and rheumatoid arthritis: This would lead to hypercitrullination and cell death, resulting in the release of substantial amounts of citrullinated epitopes in the extracellular environment, which on their turn could breach tolerance.139 The same study also suggested that in RA patients, the relationship between HLA‐SE alleles and the presence of ACPA is limited to the individuals exposed to Aa. However, this latter observation was not reproduced when tested in another cohort.140