A triad of somatic mutagenesis converges in self-reactive B cells to cause a virus-induced autoimmune disease. - Young C; Singh M; Jackson KJL; Field MA; Peters TJ; Angioletti-Uberti S; Frenkel D; Ravishankar S; Gupta M; Wang JJ; Agapiou D; Faulks ML; et al. (Immunity, 2025)