Review of clinical and basic approaches to corneal endotheliitis

Corneal endotheliitis was first reported as an autoimmune disease by Khodadoust in 1982. Thereafter, herpes simplex virus (HSV) was detected as a causative agent, and corneal endotheliitis was classified as an infectious disease. However, most primary corneal endotheliitis had been idiopathic. In 2006, cytomegalovirus (CMV) DNA was detected in a case of corneal endotheliitis, and other reports on CMV endotheliitis from Asian countries established it as a new clinical entity. Limited studies have reported clinical findings, and the pathogenesis of HSV and CMV corneal endotheliitis is unknown. Therefore, this review describes what is currently known about the pathogenesis of HSV and CMV endotheliitis by way of previously reported case studies and basic research. In addition, we review work by our own group regarding the role of Toll-like receptor 9 and the results of transcriptome analysis after HSV infection in an in vitro model using immortalized human corneal endothelial cells. It is critical to diagnose corneal endotheliitis early to provide effective treatment with ganciclovir or valganciclovir and prevent the loss of corneal endothelial cells. Therefore, we hope that these in vitro results may provide further information to help elucidate the in vivo pathogenesis of HSV and CMV endotheliitis.