Immunology in the clinic review series; focus on type 1 diabetes and viruses: enterovirus, thymus and type 1 diabetes pathogenesis.

Thymus dysfunction, especially immune suppression, is frequently associated with various virus infections. Whether viruses may disturb the thymus function and play a role in the pathogenesis of autoimmune diseases is an open issue. Enteroviruses, especially Coxsackievirus B4 (CV-B4), have been largely suggested as potential inducers or aggravating factors of type 1 diabetes (T1D) pathogenesis in genetically predisposed individuals. Several pathogenic mechanisms of enterovirus-induced T1D have been suggested. One of these mechanisms is the impairment of central self-tolerance due to viral infections. Coxsackievirus-B4 is able to infect murine thymus in vitro and in vivo and to infect human thymus in vitro. Thymic epithelial cells and thymocytes are targets of infection with this virus, and several abnormalities, especially disturbance of maturation/differentiation processes, were observed. Altogether, these data suggest that CV-B infection of thymus may be involved in the pathogenesis of T1D. Further investigations are needed to explore this hypothesis.