PRTN3 and rheumatoid arthritis: Moreover, anti-citrullinated protein antibody (ACPA) titers correlate with plasmablast-derived antibody production, underscoring their contribution to pathogenic humoral immunity in RA [108,109].ELS formation, present in approximately 40% of patients with RA, creates specialized microenvironments containing follicular dendritic cells, T follicular helper cells, and actively differentiating B cells, thereby sustaining local plasmablast differentiation and tissue-restricted autoimmunity [107,110].