Relevance of animal models to human uveitis

Uveitis represents a wide spectrum of intraocular inflammatory conditions and includes various autoimmune and infectious etiologies. The relevance of animal models of uveitis to human diseases remains a key issue with major implications for the translational research and development of therapeutic strategies. Histopathological findings in patients with Vogt-Koyanagi-Harada disease, birdshot retinochoroidopathy and anterior uveitis are correlated to those observed in different animal models. Even though evidence based on histopathology is usually irrefutable, similar features may be due to different disease mechanisms. Analysis of triggering factors, determination of cellular populations and immune microenvironment should prevail over clinical phenotype evaluation. There is a controversy in correlating the clinical finding of nummular chorioretinal scars, commonly referred to as Dalen-Fuchs nodules, seen in the periphery of fundus in patients with chronic Vogt-Koyanagi-Harada disease with histologic observations made on such enucleated eyes. Although histopathology of the lesions consisted of focal chorioretinal scars with loss of RPE, there was no consensus about the histologic nature of the nummular chorioretinal scars, particularly whether they represent Dalen-Fuchs nodules. Based on the immunogenetic background, there may be different forms of one specific disease with variable phenotypic expression. This review discusses the importance of experimental models in the light of immunologic alterations and histopathological features in human uveitic entities.