TLR9 and infection: For example: 1) viral infections: infections by viruses that activate TLR3, TLR7, or TLR9 may act as triggers in genetically predisposed individuals (42); 2) thymic microenvironment: environmental factors influencing the thymic microenvironment can exacerbate TLRs-mediated immune responses (36), promoting thymic hyperplasia and ectopic germinal center formation in MG patients.