However, the molecular features of the tonsillar germinal center (GC) microenvironment-the central site for IgA class switching and mucosal B-cell activation-remain poorly characterized, particularly in relation to glomerular injury severity.<h4>Methods</h4>In this exploratory case-control study, we analyzed tonsils from biopsy-proven IgAN (n=5) and matched habitual tonsillitis controls (n=5). The gene discussed is CD79A; the disease is tonsillitis.