Role of IL-10 gene polymorphisms in intermediate and HLA-B27-associated uveitis

Managing Psoriatic Arthritis With Inflammatory Bowel Disease and/or Uveitis

Psoriatic arthritis (PsA) is a chronic inflammatory disease that presents with psoriasis (PsO), peripheral and axial arthropathy. The heterogeneity of disease presentation leads to the term "psoriatic disease (PsD)" which is thought to better encompass the range of clinical manifestations. PsA is associated with several comorbidities such as cardiovascular diseases, metabolic syndrome and other extra-articular manifestations including uveitis, and inflammatory bowel disease (IBD). While novel therapeutics are being developed following advances in our understanding of the pathogenesis of the disease, the diverse combinations of PsA with its various comorbidities still pose a clinical challenge in managing patients with PsA. This article reviews our current understanding of the pathogenesis of PsA and how various pathways in the pathogenesis lead to the two comorbid extra-articular manifestations - uveitis and IBD. We also review current evidence of treatment strategies in managing patients with PsA with comorbidities of uveitis and/or IBD.

Deficiency of IL-27 Signaling Exacerbates Experimental Autoimmune Uveitis with Elevated Uveitogenic Th1 and Th17 Responses

Human uveitis is an autoimmune disease of the central nervous system that is characterized by ocular inflammation with the involvement of uveitogenic Th1 and Th17 responses. In experimental autoimmune uveitis (EAU), the animal model for human uveitis, both responses are proven to be critical in disease development. Therefore, targeting both Th1 and Th17 cells has therapeutic implication for disease resolution. IL-27 is a multifunctional cytokine that can either promote or inhibit T cell responses and is implicated in both autoimmune and infectious diseases. The aim of this study is to characterize the role of IL-27/IL-27R signaling in regulating uveitogenic Th1/Th17 responses in EAU. By immunizing IL-27Rα^-/- mice and their wild-type (WT) littermates for EAU, we demonstrated that IL-27 signaling deficiency exacerbated EAU with severe ocular inflammation and impairment of visual function. Furthermore, there was a significant increase in the eye-infiltrating Th1 and Th17 cells in IL-27Rα^-/- EAU mice compared to WT. Their retinal antigen-specific Th1 and Th17 responses were also significantly increased, as represented by the elevation of their signature cytokines, IFN-γ and IL-17A, respectively. We also observed the upregulation of another pathogenic cytokine, granulocyte-macrophage colony-stimulating factor (GM-CSF), from effector T cells in IL-27Rα^-/- EAU mice. Mechanistic studies confirmed that IL-27 inhibited GM-CSF production from Th17 cells. In addition, the induction of IL-10 producing type 1 regulatory T (Tr1) cells was impaired in IL-27Rα^-/- EAU mice. These results identified that IL-27 signaling plays a suppressive role in EAU by regulating multiple CD4⁺ cell subsets, including the effector Th1 and Th17 cells and the regulatory Tr1 cells. Our findings provide new insights for therapeutic potential in controlling uveitis by enhancing IL-27 signaling.

Uveitis as an Open Window to Systemic Inflammatory Diseases

Spondyloarthritis (Spa), Behçet's disease (BD) and sarcoidosis are major systemic inflammatory diseases worldwide. They are all multisystem pathologies and share a possible ocular involvement, especially uveitis. We hereby describe selected cases who were referred by ophthalmologists to our internal medicine department for unexplained uveitis. Physical examination and/or the use of laboratory and imaging investigations allowed to make a diagnosis of a systemic inflammatory disease in a large proportion of patients. In our tertiary referral center, 75 patients have been diagnosed with Spa (n = 20), BD (n = 9), or sarcoidosis (n = 46) in the last two years. There was a significant delay in the diagnosis of Spa-associated uveitis. Screening strategies using Human Leukocyte Antigen (HLA)-B27 determination and sacroiliac magnetic resonance imaging in patients suffering from chronic low back pain and/or psoriasis helped in the diagnosis. BD's uveitis affects young people from both sexes and all origins and usually presents with panuveitis and retinal vasculitis. The high proportion of sarcoidosis in our population is explained by the use of chest computed tomography (CT) and 18F-fluorodeoxyglucose positron emission tomography CT that helped to identify smaller hilar or mediastinal involvement and allowed to further investigate those patients, especially in the elderly. Our results confirm how in these sight- and potentially life-threatening diseases a prompt diagnosis is mandatory and benefits from a multidisciplinary approach.

The associations between interleukin 10 polymorphisms and susceptibility to autoimmune uveitis - a meta-analysis

Autoimmune uveitis is an ocular inflammatory disease that is associated with genetic factors. Interleukin 10 (IL-10) is an immune-regulatory cytokine of autoimmune diseases. IL-10 is considered a candidate gene for uveitis. We evaluate the association of IL-10 with susceptibility to autoimmune uveitis. The results from seven studies were pooled in the meta-analysis, covering a total of 2893 cases of uveitis and 4873 controls. Published literature from MEDLINE and Embase was retrieved. Meta-analyses were conducted on the associations between autoimmune uveitis and the -1082 A/G and -819 C/T polymorphisms of the IL-10 gene. The meta-analysis revealed no association between uveitis and the IL-10 -1082 A allele (OR = 0.91, 95% CI = 0.64-1.30, p = 0.62). The recessive, dominant, and homozygous models of the IL-10 -1082 A/G allele also suggested no association between autoimmune uveitis and each genotype. The meta-analysis revealed significant association between uveitis and the -892 C allele (OR = 0.81, 95% CI = 0.67-0.98, p = 0.03). In addition, significant association was found in homozygous models (OR = 0.58, 95% CI = 0.36-0.92, p = 0.02). However, the dominant and recessive models of the IL-10 -819 C/T polymorphisms showed no association between uveitis and each genotype. This meta-analysis showed that the -1082 A/G polymorphisms of IL-10 were not associated with autoimmune uveitis, but the -819 C/T polymorphisms were significantly associated with uveitis.

Single-Nucleotide Polymorphisms in IL23R-IL12RB2 (rs1495965) Are Highly Prevalent in Patients with Behcet's Uveitis and Vary Between Populations

Purpose: To test the frequency of single-nucleotide polymorphisms in the IL-10, IL23R-IL12RB2 genes in patients with Behcet's uveitis. Methods: Blood samples were collected from 89 Israeli and Turkish patients, and from healthy control subjects of different origins. Genomic DNA was extracted from peripheral blood leukocytes and genotyped. Results: The risk allele, A, in rs1800871, of IL-10 gene was highly prevalent in Behcet's uveitis and healthy control samples alike; highest among the Turkish groups. Prevalence of G allele, in rs1495965, in the IL23R-IL12RB2 gene was high in Behcet's uveitis patients, and among healthy Turkish and Israelis of Middle Eastern origin, while lower among the other Israeli control group (77.9%, 78.9%, 27.8%, respectively, P < 0.001). Conclusion: Our findings highlight the differences between populations and may account for the increased prevalence of the disease among Turkish and Israelis of Middle Eastern origin. Further studies are required to map other healthy and affected populations.

HLA-B27 Anterior Uveitis: Immunology and Immunopathology

Acute anterior uveitis (AAU) is the commonest type of uveitis and HLA-B27 AAU is the most frequently recognized type of acute anterior uveitis and anterior uveitis overall. Recent evidence indicates that acute anterior uveitis is a heterogenous disease, is polygenic and is frequently associated with the spondyloarthropathies (SpA). Studies of patients with AAU and animal models of disease indicate a role for innate immunity, the IL-23 cytokine pathway and exogenous factors, in the pathogenesis of both SpA and acute anterior uveitis. Recently described genetic associations cluster around immunologic pathways, including the IL-17 and IL-23 pathways, antigen processing and presentation, and lymphocyte development and activation. Patients with ankylosing spondylitis (AS) and AAU share other genetic markers, such as ERAP-1, which show strong evidence of gene-gene interaction and point to new mechanisms of disease pathogenesis. These observations have major implications for understanding the pathogenesis of HLA-B27 diseases, such as AAU, and may lead to the development of more specific therapy for AAU. Received 6 January 2016; revised 6 February 2016; accepted 18 February 2016; published online 31 May 2016.