A proteomic approach for studying the pathogenesis of spontaneous equine recurrent uveitis (ERU).

This research study investigates the underlying causes of equine recurrent uveitis (ERU), an eye disease that often leads to blindness in horses globally, but also serves as a model for human autoimmune uveitis. By studying the autoantibody-binding pattern from ERU cases to the retinal proteome, the researchers identify and characterize new autoantigens: Cellular Retinaldehyde-Binding Protein (CRALBP) and Malate Dehydrogenase (MDH). The paper reports differing effects of these autoantigins on causing uveitis in rats and horses.

Understanding ERU and its Relevance to Human Autoimmune Uveitis

• ERU is a prevalent eye-related ailment in horses that often results in blindness. Despite its prevalence among equines, its pathogenesis remains poorly understood.
• Interestingly, ERU serves as a spontaneous model for studying human autoimmune uveitis due to similarities in the conditions. Thus, understanding the mechanisms behind ERU may assist in research towards autoimmune conditions in humans.

Detection and Characterization of New ERU Autoantigens

• The researchers focused on illuminating the autoantibody-binding pattern in ERU cases by analyzing the retinal proteome.
• This approach was pivotal in identifying two novel autoantigens associated with ERU: CRALBP and MDH. Before this discovery, these autoantigens were not linked to the disease.
• Particularly important was evidence of B- and T-cell autoreactivity to both these autoantigens in ERU cases, confirming their role in the immune response associated with the disease.

Evaluating the Pathological Relevance of CRALBP and MDH

• The researchers observed different results when assessing the impact of the identified autoantigens on inducing uveitis.
• Testing revealed that CRALBP induced uveitis with high incidence in both rats and horses. This suggests that CRALBP may play a key role in the development of ERU, and potentially human autoimmune uveitis.
• Interestingly, when assessing MDH, it was found that it only caused uveitis in Lewis rats, but not in horses. This highlights a potential divergence in how ERU and other uveitis forms might manifest across different species.