 Evidence for the T cell @-@ mediated mechanism of mucosal destruction is strong , but the exact triggers for this process are unknown and are thought to be multiple and varied from one person to the next . This suggests that there are a number of possible triggers , each of which is capable of producing the disease in different subgroups . In other words , different subgroups appear to have different causes for the condition . These can be considered in three general groups , namely primary immuno @-@ dysregulation , decrease of the mucosal barrier and states of heightened antigenic sensitivity ( see below ) . <unk> factors in aphthous stomatitis are also sometimes considered as either host @-@ related or environmental . 
