Birdshot chorioretinopathy (BSCR) is a rare form of autoimmune uveitis that can lead to severe visual impairment. Intriguingly, >95% of cases carry the HLA-A29 allele, which defines the strongest documented HLA association for a human disease. We have conducted a genome-wide association study in 96 Dutch and 27 Spanish cases, and 398 unrelated Dutch and 380 Spanish controls. Fine-mapping the primary MHC association through high-resolution imputation at classical HLA loci, identified HLA-A*29:02 as the principal MHC association (odds ratio (OR) = 157.5, 95% CI 91.6-272.6, P = 6.6 × 10(-74)). We also identified two novel susceptibility loci at 5q15 near ERAP2 (rs7705093; OR = 2.3, 95% CI 1.7-3.1, for the T allele, P = 8.6 × 10(-8)) and at 14q32.31 in the TECPR2 gene (rs150571175; OR = 6.1, 95% CI 3.2-11.7, for the A allele, P = 3.2 × 10(-8)). The association near ERAP2 was confirmed in an independent British case-control samples (combined meta-analysis P = 1.7 × 10(-9)). Functional analyses revealed that the risk allele of the polymorphism near ERAP2 is strongly associated with high mRNA and protein expression of ERAP2 in B cells. This study further defined an extremely strong MHC risk component in BSCR, and detected evidence for a novel disease mechanism that affects peptide processing in the endoplasmic reticulum.

ABSTRACT.Purpose: To report the anatomical pattern and etiological spectrum of uveitis in an urban multi-ethnic population from Barcelona, Spain. General and specific epidemiological data for the most prevalent aetiologies are also calculated. Methods: A cross-sectional study of consecutive uveitis cases was performed between 1 January 2009 and 31 December 2012. Exogenous endophthalmitis, surgery-related, post-traumatic and toxic uveitis along with masquerade syndromes were excluded. Anatomical (Standard Uveitis Nomenclature criteria) and aetiological patterns (by tailored tests), age, sex, geographical origin and laterality were analysed. Mean incidence and prevalence were calculated for a mid-period reference population. Results: From 1022 patients included, 52% were anterior uveitis (AU), 23% posterior, 15% panuveitis and 9% intermediate uveitis. Aetiologically, 26% were unclassifiable, 29% infectious, 25% associated with systemic immune diseases, and 20% corresponded to ocular-specific syndromes. Among classified causes, herpesvirus (12%), toxoplasma (7%), Behc ßet's disease (BD) (5%), HLA-B27-isolated AU (5%), ankylosing spondylitis (5%), tuberculosis-related uveitis (TRU) (5%), birdshot chorioretinopathy (3%) and sarcoidosis (3%) were the most frequent. Non-Spanish origin was recorded in 22%, with 47% of VogtKoyanagi-Harada and 36% of toxoplasma cases coming from South America, 10% of BD and 11% of TRU from Africa and 24% of TRU cases from Asia. A mean annual incidence of 51.91 cases/100 000 inhabitants was found for the referral population. Conclusion: In our referral area, 74% of the uveitis cases can be correctly classified. A large myriad of uveitis aetiologies with a strong geographical origin burden are found in Western urban multi-ethnic populations.

These data suggest that TCZ is effective for treating CME in otherwise treatment-refractory cases of uveitis.

SummaryInterleukin-6 (IL-6) is a key cytokine featuring redundancy and pleiotropic activity. It plays a central role in host defence against environmental stress such as infection and injury. Dysregulated, persistent interleukin (IL)-6 production has been implicated in the development of various autoimmune, chronic inflammatory diseases and even cancers. Significant elevation of IL-6 has been found in ocular fluids derived from refractory/chronic uveitis patients. In experimental autoimmune uveitis models with IL-6 knock-out mice, IL-6 has shown to be essential for inducing inflammation. IL-6 blockade can suppress acute T helper type 17 (Th17) responses via its differentiation and, importantly, can ameliorate chronic inflammation. Tocilizumab, a recombinant humanized anti-IL-6 receptor antibody, has been shown to be effective in several autoimmune diseases, including uveitis. Herein, we discuss the basic biology of IL-6 and its role in development of autoimmune conditions, focusing particularly on non-infectious uveitis. It also provides an overview of efficacy and safety of tocilizumab therapy for ocular inflammatory diseases.