A lab-made cyclic peptide called Clarstatin was given to mice with an eye inflammation model. It cut the disease severity by 30‑80% and lowered key inflammatory signals, doing about as well as steroids. The work shows the peptide can act as an anti‑inflammatory agent in animals, but it’s still far from being a usable supplement or drug for people.

Polymorphism and mutations of human leukocyte antigens (HLAs) and calreticulin are risk factors for uveitis. Here, we sought to determine the therapeutic effects of Clarstatin, a cyclic peptide antagonist of the HLA shared-epitope-calreticulin interaction, in experimental autoimmune uveitis (EAU) models. Mice were injected with Clarstatin intraperitoneally and its effect was compared to that of corticosteroid. EAU was evaluated clinically and histologically. Ocular infiltration of CD45+ hematopoietic cells and splenocyte CD4+ expression were determined using immunofluorescence and flow cytometry (fluorescence-activated cell sorting [FACS]). ELISA was used to measure the ocular level of the proinflammatory cytokines. Clarstatin significantly ameliorated the severity of EAU in the C57BL/6J mild and the B10.RIII severe mice models. There was a significant dose and time-dependent decrease, in the range of 30% to 80%, in the clinical score (P < 0.05), histological score (P < 0.05), and number of retinal and spleen CD45+ cells (P < 0.05 and P < 0.001, respectively), a comparable effect to corticosteroid. Clarstatin reduced the intraocular levels of interleukin 6 (IL-6; P < 0.05) and monocyte chemoattractant protein-1 (MCP-1; P < 0.01) by 41% and 59%, respectively. Systemic delivery of Clarstatin significantly improved mild and severe EAU. Its potential anti-inflammatory therapeutic effects represent a novel mode of treatment in ocular inflammation. It may also be a relevant treatment modality in systemic autoimmune conditions in which calreticulin plays a role in their pathogenesis.