Acute anterior uveitis and HLA-B27

Mimickers of anterior uveitis, scleritis and misdiagnoses- tips and tricks for the cornea specialist

BACKGROUND

Anterior uveitis, inflammation of the anterior chamber and related structures, is a cohort of diseases that can present to almost any general or sub-specialty Ophthalmology practice. Its features classically involve anterior chamber cell and flare. Below the surface of these two signs exist a panoply of diagnoses. BODY: The purpose of this review is to provide a general framework for diagnoses of anterior uveitis that are often missed as well as non-uveitic pathologies that often mimic anterior uveitis. Diagnostic deviation in either direction can have vision-threatening and rarely life-threatening consequences for patients. Using a comprehensive literature review we have collected a broad spectrum of etiologies of anterior uveitis that are easily missed and non-uveitic pathologies that can masquerade as anterior uveitis.

CONCLUSIONS

We present a focused review on specific misdiagnosed anterior uveitis pathologies and some of the conditions that can masquerade as anterior uveitis and scleritis.

Progress in the genetics of uveitis

Uveitis is the most common form of intraocular inflammatory disease and is a significant cause of visual impairment worldwide. Aetiologically, uveitis can also be classified into infectious uveitis and non-infectious uveitis. The common non-infectious forms of uveitis include acute anterior uveitis (AAU), Behçet’s disease (BD), Vogt-Koyanagi-Harada (VKH) disease, birdshot chorioretinopathy (BSCR), sarcoid uveitis. In addition, a few monogenic autoinflammatory disorders can also cause uveitis, such as Blau Syndrome and haploinsufficiency of A20 (HA20). Although the exact pathogenesis of non-infectious uveitis is still unclear, it is well-recognised that it involves both genetic and environmental risk factors. A hallmark of uveitis is its strong associations with human leucocyte antigens (HLA). For examples, AAU, BD and BSCR are strongly associated with HLA-B27, HLA-B51, and HLA-A29, respectively. In uveitis studies, multiple GWAS have successfully been conducted and led to identification of novel susceptibility loci, for example, IL23R has been identified in BD, VKH and AAU. In this review, we summarize the latest progress on the genetic associations of both HLA and non-HLA genes with major forms of uveitis, including AAU, BD, VKH, BSCR, sarcoid uveitis, Blau Syndrome and HA20, and potential future research directions.

Microbiota and Ocular Diseases

Recent advances have identified significant associations between the composition and function of the gut microbiota and various disorders in organ systems other than the digestive tract. Utilizing next-generation sequencing and multiomics approaches, the microbial community that possibly impacts ocular disease has been identified. This review provides an overview of the literature on approaches to microbiota analysis and the roles of commensal microbes in ophthalmic diseases, including autoimmune uveitis, age-related macular degeneration, glaucoma, and other ocular disorders. In addition, this review discusses the hypothesis of the "gut-eye axis" and evaluates the therapeutic potential of targeting commensal microbiota to alleviate ocular inflammation.

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.

Triggering factors associated with a new episode of recurrent acute anterior uveitis

To identify triggering factors for the next inflammatory episode of recurrent acute anterior uveitis (RAAU), a 1:1 case-control study was conducted. We interviewed RAAU patients with recent acute anterior uveitis attack and quiescent controls for their information during a previous month using Srithanya Stress Test (ST-5) and questionnaires about potential triggering factors. Asymptomatic controls were matched for age (± 5 years), sex, and HLA-B27. There were 39 pairs of cases and controls. Patients who recently experienced a uveitis attack demonstrated higher mean ST-5 scores (3.7 ± 2.9 vs 0.7 ± 1.1) and shorter sleep time (6.3 ± 1.4 vs 7.4 ± 0.7 h per day) compared with their controls. In the multivariate conditional logistic regression analysis, ST-5 score ≥ 3 (OR 9.07, 95% CI 1.14-72.16, p = 0.037) and sleep time < 7 h per day (OR 12.12, 95% CI 1.37-107.17, p = 0.025) were more likely to trigger a uveitis attack in RAAU accounted for patients' age, sex, HLA- B27 positivity, and presence of concurrent anti-inflammatory drugs for co-existing diseases. Other suspected triggering factors were not found to have any significant association. In short, stress and inadequate sleep may lead to the future episode of acute anterior uveitis in RAAU. Both physical and emotional stress management should be advised to RAAU patients to minimize recurrences and further complications.

Clinical Features of Acute Anterior Uveitis with Complicated Course in a Slovenian Patient Population

PURPOSE

To report on patients who needed hospitalization due to acute anterior uveitis (AAU) and within this group to compare clinical features and outcomes of treatment of HLA-B27+ and HLA-B27- AAU in the population of Slovenian patients.

METHODS

Retrospective study of hospitalized patients with AAU in the last 39 months at the Eye Hospital in Ljubljana. The data of AAU patients were retroactively studied and compared on the basis of HLA-B27 antigen presence: visual acuity upon admission, visual outcome, the presence of hypopyon, fibrinous reaction, posterior iris synechiae, and complications, such as elevated intraocular pressure, cataract, and cystoid macular edema (CME). We compared the investigations in the diagnostic process, the associated systemic disease, and the treatment administered. Statistical analyses included Student's t-test Fisher's exact test, and the Kolmogorov-Smirnov test. A p value of <0.05 was considered statistically significant.

RESULTS

A total of 37 hospitalized patients with AAU were included. HLA-B27 antigen was detected in 73% of patients. In the HLA-B27+ group, women were more commonly affected, while the males were more affected in the HLA-B27- group. The occurrence of fibrin was significantly more common in HLA-B27+ patients, as well as hypopyon and posterior synechiae; only fibrin reached the statistical significance (p < 0.05). The incidence of cataracts, ocular hypertension, and glaucoma did not differ significantly between the two groups. HLA-B27+ AAU was more often associated with systemic diseases, and patients in this group were more frequently treated with systemic immunomodulatory drugs, however, no difference reached the statistical significance. We did not notice any major differences in the final visual acuity in the comparing groups.

CONCLUSION

Almost ¾ of AAU patients that required hospitalization were HLA-B27+. In this group, disease was more severe, more frequently associated with ocular complications and systemic disease, but final visual acuity was the same in both groups. HLA-B27 typing has no prognostic value in our group of complicated AAU patients, but it eases the decision about necessary diagnostics and treatment.

Ocular manifestations of inflammatory bowel diseases: an update for gastroenterologists

Inflammatory bowel diseases (IBD), that includes ulcerative colitis and Crohn's disease, can affect not only the gastrointestinal tract but a wide spectrum of organs. The extra-intestinal manifestations (EIMs) are one of the most challenging aspect of IBD, playing a significant role for the lifetime care and the quality of life of patients. Ocular manifestations are the third most frequent EIMs, preceded by articular and dermatological ones. The aim of this narrative review is to describe the different types of ocular involvements, focusing on their clinical management. Uveitis and episcleritis are the most common ocular EIMs, differing for many aspects. Uveitis are unrelated with IBD activity and they even precede the onset of the intestinal disease, while episcleritis are common defined as a good mark of IBD activity. Pain is uncommon in most cases of episcleritis, while severe eye pain and photophobia are the most frequent onset of anterior uveitis. Less common but even more severe, are orbital pseudotumor or posterior segment involvement. Most of the ocular EIMs can be successfully treated with topic and oral steroids and the underlying therapy for IBD can reduce or cut out at all the recurrence of these manifestations. Symptoms are commonly not specific, in some cases being unnoticed for years leading to permanent ocular consequences. Cooperation between different specialists is crucial to avoid all the possible consequences of a non-treated EIMs, especially for ocular ones.

Potential predictors for frequent relapse in human leukocyte antigen-B27-associated uveitis

PURPOSE

To identify potential predictors for frequent relapse in a cohort of patients with human leukocyte antigen (HLA)-B27-associated uveitis in a tertiary referral center at the initial visit.

METHODS

This retrospective cohort study comprised 130 patients diagnosed with HLA-B27-associated uveitis. Subjects were divided into two groups according to the frequency of uveitis attacks (number/year): frequent relapse (FR) (who relapsed more than twice a year, 38) and infrequent relapse (IR) group (who relapsed twice or less than twice a year, 92).

RESULTS

The FR group presented more often with hypopyon or posterior synechiae at the initial presentation. Interestingly, posterior segment involvements including vitritis, vasculitis, or cystoid macular edema were not significantly different between the groups. In terms of laboratory findings, the erythrocyte sedimentation rate (ESR) was higher in the FR group. Multivariate Cox hazards analysis showed male sex, the presence of hypopyon, and ESR to be potential predictive factors for frequent relapse.

CONCLUSION

We found that male sex, hypopyon at presentation, and high ESR are potential predictors for frequent relapse in HLA-B27-associated uveitis. Identifying patients at higher risk of relapse could provide important information for patients, allowing patients to understand their condition and increase their acceptance of strict management.

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.

Genetic of uveitis

Immune-mediated uveitis may be associated with a systemic disease or may be localized to the eye. T-cell-dependent immunological events are increasingly being regarded as extremely important in the pathogenesis of uveitis. Several studies have also shown that macrophages are major effectors of tissue damage in uveitis. Uveitis phenotypes can differ substantially, and most uveitis diseases are considered polygenic with complex inheritance patterns. This review attempts to present the current state of knowledge from in vitro and in vivo research on the role of genetics in the development and clinical course of uveitis. A review of the literature in the PubMed, MEDLINE, and Cochrane databases was conducted to identify clinical trials, comparative studies, case series, and case reports describing host genetic factors as well as immune imbalance which contribute to the development of uveitis. The search was limited to primary reports published in English with human subjects from 1990 to the present, yielding 3590 manuscripts. In addition, referenced articles from the initial searches were hand searched to identify additional relevant reports. After title and abstract selection, duplicate elimination, and manual search, 55 papers were selected for analysis and reviewed by the authors for inclusion in this review. Studies have demonstrated associations between various genetic factors and the development and clinical course of intraocular inflammatory conditions. Genes involved included genes expressing interleukins, chemokines, chemokine receptors, and tumor necrosis factor and genes involved in complement system. When considering the genetics of uveitis, common threads can be identified. Genome-wide scans and other genetic methods are becoming increasingly successful in identifying genetic loci and candidate genes in many inflammatory disorders that have a uveitic component. It will be important to test these findings as uveitis-specific genetic factors. Therefore, the burgeoning understanding of the human genome promises to result in new insight into the pathogenesis of uveitis.

TNF receptor-associated factor 5 gene confers genetic predisposition to acute anterior uveitis and pediatric uveitis

Introduction

TNF Receptor-Associated Factor 5 (TRAF5) has been shown to be associated with autoimmune disease. The current study sought to investigate the potential association of TRAF5 with acute anterior uveitis (AAU) and pediatric uveitis in Han Chinese.

Methods

Three TRAF5 SNPs were analyzed in 450 AAU patients with or without ankylosing spondylitis (AS), 458 pediatric uveitis patients, and 1,601 healthy controls by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) or TaqMan SNP Genotyping Assay. Numerous variables were evaluated, including age, sex distribution, and clinical and laboratory observations.

Results

Two SNPs (rs6540679, rs12569232) of TRAF5 were associated with pediatric uveitis, and rs12569232 also showed a relation with the presence of microvascular leakage. No significant associations were found when patients were subdivided according to their rheumatoid factor (RF) or anti-nuclear antibody (ANA) status or whether they had juvenile idiopathic arthritis (JIA). Rs12569232 predisposed to AAU and its subgroups (with ankylosing spondylitis (AS) or HLA-B27 positive). No association was found between rs10863888 and either pediatric uveitis or AAU.

Conclusion

This study revealed that TRAF5 is involved in the development of AAU and pediatric uveitis. Further stratified analysis according to the clinical and laboratory observations suggested that rs12569232/TRAF5 may play a role in the development of retinal vasculitis.

The roles of genetic factors in uveitis and their clinical significance

BACKGROUND

Uveitis is a diverse group of intraocular inflammatory disease and is a significant cause of visual loss worldwide. Recent studies have identified various endogenous immune mechanisms and genetic factors that are involved in the pathogenesis of uveitis. This review provides an overview on the role of genetics in the development and clinical course of uveitis.

METHODS

PUBMED was used for literature search, and articles published from 1970 to 2012 that evaluated the genetic associations and mechanisms involved in the development and clinical features of uveitis were included.

RESULTS

Studies have demonstrated associations between various genetic factors and the development and clinical course of intraocular inflammatory conditions. Genes involved included genes expressing interleukins, chemokines, chemokine receptors, and tumor necrosis factor and genes involved in complement system, oxidation, and other intracellular molecular pathways.

CONCLUSION

Multiple genetic factors play important roles in the pathogenesis of uveitis and may influence the clinical course of uveitis. Further studies to investigate the genetic mechanisms of uveitis might identify additional genetic associations and might have the potential for identifying novel therapeutic targets in the treatment of intraocular inflammation.

Managing IBD outside the gut: ocular manifestations

Extraintestinal manifestations are common in inflammatory bowel disease (IBD), being reported in over 25% of patients. Ocular complications of IBD occur in around 10% of cases, but may precede systemic symptoms and are usually nonspecific. Complications of therapy, such as cataracts or glaucoma from steroid use or keratoconjunctivitis sicca related to 5-aminosalicylic acid medications, may also involve the eyes. The pathogenesis remains unclear, but factors such as the extent of intestinal disease, disease activity, and the presence of associated arthritis have been associated with ocular involvement. Conjunctivitis, episcleritis, scleritis and uveitis are by far the most common ophthalmic complications of IBD. However, posterior uveitis, intraretinal hemorrhages, vasculitis, choroiditis, optic neuropathy, and vaso-occlusive phenomena may also occur. The most frequent severe ocular manifestation is anterior uveitis (more common in women). It usually presents as a mild anterior nongranulomatous uveitis (60% of the cases). The inflammation in the eye and the inflammation in the gut are rarely correlated. Patients with uveitis, scleritis, and other anterior segment inflammation usually respond to steroids (topical, periocular or systemic). If the inflammation is resistant to steroids, or if appreciable steroid adverse effects are encountered, systemic immunosuppressive treatment should be considered; this is more likely in HLA-B27-positive patients with uveitis. Evaluation of the eye should be a routine component in the care of patients with IBD.

HLA and idiopathic uveitis

Idiopathic uveitis is the most common form of chronic uveitis seen in our area. Characteristically it is a heterogeneous entity in its clinical severity, evolution and therapeutic response, and immune mechanisms are thought to be involved. The phenotype frequencies of HLA antigens were studied in 62 patients with idiopathic uveitis and compared with their frequencies in northern Portugal. The authors also included two groups with a well known immunogenetic background-Behçet's syndrome (BS: n=20) and ankylosing spondylitis (AS: n=18) which are, respectively, the most severe and the most frequent of the rheumatic forms in the area. An increased frequency of HLA B5(B51) in Behçet uveitis (55%; RR=8) was confirmed in the authors' population. They also found in idiopathic uveitis an increased risk for HLA B27 (RR=14). HLA B27 positive idiopathic uveitis was predominantly unilateral (80%) and anterior (97%), whereas B27 negative forms showed a higher prevalence of severe panuveitis. In conclusion, the authors confirmed in their population the association of HLA B27 with uveitis, and HLA B51 with Behçet uveitis. In this last entity an intermediate frequency between northern Europe and the Mediterranean area was observed.

Comparison of performance of the Assessment of SpondyloArthritis International Society, the European Spondyloarthropathy Study Group and the modified New York criteria in a cohort of Chinese patients with spondyloarthritis

Early diagnosis of spondyloarthritis (SpA) is essential as anti-tumor necrosis factor therapy can achieve significant symptomatic relief and control of disease activity. This study aims to compare the clinical characteristics, disease activity, and functional status of a Chinese cohort of SpA patients who were re-classified into ankylosing spondylitis (AS) patients fulfilling the modified New York (MNY) criteria, those with undifferentiated SpA (USpA) fulfilling the European Spondyloarthropathy Study Group (ESSG) classification criteria only (USpA/ESSG) and those who fulfill Assessment of SpondyloArthritis International Society (ASAS) only (USpA/ASAS). Disease activity was evaluated by Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), severity of morning stiffness, patient global assessment, and C-reactive protein. Functional status was evaluated by Bath Ankylosing Spondylitis Functional Index (BASFI), modified Schober index, and dimension of chest expansion. One hundred and twenty-eight patients with disease duration of 16.3 ± 10.4 years were recruited. Patients in USpA/ESSG and USpA/ASAS were significantly younger (p = 0.01), had shorter disease duration (p < 0.01), and lower BASFI (p = 0.03) than established AS patients. All three groups have active disease with comparable BASDAI >3. BASFI correlated inversely with dimension of chest expansion and negatively modified Schober index in AS patients (p < 0.01) and modestly with BASDAI (r = 0.25, p < 0.01). BASFI correlated moderately with BASDAI in USpA/ESSG (r = 0.61, p < 0.01) but not with chest expansion or modified Schober index. Compared with established AS patients recognized by MNY criteria, patients fulfilling USpA defined by ESSG or ASAS criteria had earlier disease, as active disease and less irreversible functional deficit.

Current approach in diagnosis and management of anterior uveitis

Uveitis is composed of a diverse group of disease entities, which in total has been estimated to cause approximately 10% of blindness. Uveitis is broadly classified into anterior, intermediate, posterior and panuveitis based on the anatomical involvement of the eye. Anterior uveitis is, however, the commonest form of uveitis with varying incidences reported in worldwide literature. Anterior uveitis can be very benign to present with but often can lead to severe morbidity if not treated appropriately. The present article will assist ophthalmologists in accurately diagnosing anterior uveitis, improving the quality of care rendered to patients with anterior uveitis, minimizing the adverse effects of anterior uveitis, developing a decision-making strategy for management of patients at risk of permanent visual loss from anterior uveitis, informing and educating patients and other healthcare practitioners about the visual complications, risk factors, and treatment options associated with anterior uveitis.

Immune response genes in uveitis

Uveitis is defined as an intraocular inflammation induced by different etiologies. Though the precise pathogenesis is still unknown, accumulating evidence shows that both innate and adaptive immune responses may be predominant mechanisms involved in the development of uveitis. Toll-like receptors have been shown to be expressed in the human eye and play an important role in infectious uveitis. The NOD proteins, expressed mainly in the cytosol by APCs, recognize the products of bacteria and participate in the development of uveitis. HLA genes have been associated with some uveitis entities, including acute anterior uveitis (HLA-B27), Behcet disease (HLA-B51), birdshot retinochoroidopathy (HLA-A29), Vogt-Koyanagi-Harada syndrome (HLA-DR4), sarcoidosis, sympathetic ophthalmia, juvenile idiopathic arthritis, tubulointerstitial nephritis and uveitis (TINU) syndrome, and pars planitis (HLA-DR15). The exact mechanism whereby certain HLA genes predispose to a certain uveitis entity has not yet been elucidated. In addition, several studies have demonstrate that polymorphisms in certain immune response genes, such as tumor necrosis factor (TNF), MHC class I polypeptide-related sequence A (MICA), interleukin-1 (IL-1), and some chemokines, may contribute to the development of human uveitis. Polymorphisms in the gene coding for the costimulatory molecule known as cytotoxic T-lymphocyte antigen 4 (CTLA-4) were recently found in Chinese patients with VKH syndrome but not in patients with Behcet disease. Further developments in the unraveling of immune response genes may lead to a better understanding of human uveitis and will hopefully allow the development of novel treatment regimes.

Clinical Features and Outcomes of HLA-B27-Positive and HLA-B27-Negative Acute Anterior Uveitis in a Turkish Patient Population

PURPOSE

To compare the clinical features and outcomes of HLA-B27-positive and HLA-B27-negative acute anterior uveitis (AAU) in a large Turkish patient population.

METHODS

Forty-four patients with HLA-B27-positive AAU and 65 with HLA-B27-negative AAU were reviewed retrospectively. HLA-B27 typing, gender, laterality, clinical features (fibrinous reaction, hypopyon formation), ocular complications, medical treatment, and final visual acuity were recorded. Statistical analyses included Student's t-test, Fisher's exact test, Yate's corrected Chi2 test, and Mann-Whitney U test. A p-value of <0.05 was considered statistically significant.

RESULTS

Forty percent of all patients with AAU were found to be positive for HLA-B27 antigen. HLA-B27-positive AAU was significantly more common in males and HLA-B27-negative AAU in females. Unilateral or bilateral alternating AAU as well as fibrinous reaction and hypopyon formation were more common in HLA-B27-positive patients. Posterior iris synechiae and cataract formation were more common and systemic immunosuppressive agents were exclusively required in patients with HLA-B27-negative AAU. Visual outcome did not differ significantly between the HLA-B27-positive and HLA-B27-negative groups.

CONCLUSIONS

HLA-B27 association is less common in Turkish patients with AAU than in other populations reported in the literature. Although distinct features of HLA-B27 uveitis were confirmed in our study, visual outcome did not differ from idiopathic AAU. Therefore, we believe that HLA-B27 typing in patients with AAU helps the clinician with the diagnosis. However, it has a limited value in determining the prognosis.

High prevalence of fastidious bacteria in 1520 cases of uveitis of unknown etiology

The etiologic evaluation of uveitis is frequently unsuccessful when noninvasive methods are used. We conducted a prospective study to evaluate systematic screening for pathogens of uveitis. All patients with uveitis referred to the participating tertiary ophthalmology departments from January 2001 to September 2007 underwent intraocular and serum specimen collection. The standardized protocol for laboratory investigations included universal polymerase chain reaction (PCR)-based detection of any bacteria and mycoses, specific PCR-based detection of fastidious (difficult-to-grow) bacteria and herpes viruses, and culture of vitreous fluid. Sera were tested for fastidious bacteria. Among the 1321 included patients (1520 specimens), infection was diagnosed in 147 (11.1%) patients: 78 (53%) were caused by fastidious bacteria that included spirochetes, Bartonella species, intracellular bacteria (Chlamydia species, Rickettsia species, Coxiella burnetii), and Tropheryma whipplei; 18 by herpes viruses; and 9 by fungi. Bartonella quintana, Coxiella burnetii, Paracoccus yeei, Aspergillus oryzae, and Cryptococcus albidus were found to be associated with uveitis for the first time, to our knowledge. We recommend applying a 1-step diagnostic procedure that incorporates intraocular, specific microbial PCR with serum analyses in tertiary centers to determine the etiology of uveitis.

Repeated exacerbations of ocular inflammation with vitreous hemorrhage in a patient with HLA-B27 associated uveitis

HLA-B27 associated uveitis is characterized by recurrent alternating acute unilateral attacks of intraocular inflammation in the anterior chamber. The aim of this study was to report an unusual case of repeated exacerbations with vitreous hemorrhage in HLA-B27 associated uveitis. Thirty four-year-old man was diagnosed as HLA-B27 associated uveitis in his right eye. He showed repeated exacerbation of ocular inflammation with retinal vein dilation and small retinal hemorrhage following vitreous hemorrhage. Fluorescein fundus angiography a week before the appearance of vitreous hemorrhage showed no neovascularization. Oral prednisolone administration was started from 40mg/day with gradual tapering. About 3 weeks after the onset, most of the vitreous hemorrhage disappeared and visual acuity was improved to 20/20. Through the decreased vitreous hemorrhage, Weiss ring was detected later. The vitreous hemorrhage found in this patient is a severe exacerbation, and might be a consequence of the vitritis that leads to posterior vitreous detachment.

HLA-B27-associated acute anterior uveitis in the University Referral Centre in North Thailand: clinical presentation and visual prognosis

BACKGROUND

Acute anterior uveitis (AAU) is the most frequent type of uveitis encountered in the west. Although human leucocyte antigen (HLA)-B27-associated ankylosing spondylitis was reported in South East Asia, it is not known whether HLA-B27-associated ocular disease is prevalent in Thailand.

METHODS

A prospective study of 100 unrelated blood donors and 121 consecutive patients with AAU was carried out. All people underwent HLA-B27 typing and full ocular examination. Radiological examination of the sacroiliac joints was conducted in patients with low back pain or arthralgias.

RESULTS

The prevalence of HLA-B27 was 10% among the blood donors in contrast with 44% in the AAU group (p<0.001). The clinical characteristics of HLA-B27-associated AAU were similar to those published throughout the world (unilaterality in 74%, hypopyon in 31%, recurrent AAU in 64%). However, the increased intraocular pressure (IOP) was more common in the HLA-B-27-negative group (p = 0.03) than in their HLA-B27-positive counterparts. At least 15% of the HLA B27-positive group had radiological signs of ankylosing spondylitis.

CONCLUSION

The prevalence of HLA-B27 in the population without uveitis in Thailand is about 10% and clinical characteristics of HLA-B27-positive AAU are similar to those reported in the west. In contrast with earlier reports, HLA-B27-negative AAU in Thailand was associated with increased IOP and should be further studied.

Cytokines and chemokines in uveitis: is there a correlation with clinical phenotype?

Uveitis is a general term for intraocular inflammation and includes a large number of clinical phenotypes. As a group of disorders, it is responsible for 10% of all registered blind patients under the age of 65 years. Immune-mediated uveitis may be associated with a systemic disease or may be localized to the eye. The pro-inflammatory cytokines interleukin (IL)-1beta, IL-2, IL-6, interferon-gamma and tumor necrosis factor-alpha have all been detected within the ocular fluids or tissues in the inflamed eye together with others, such as IL-4, IL-5, IL-10 and transforming growth factor-beta. The chemokines IL-8, monocyte chemoattractant protein-1, macrophage inflammatory protein (MIP)-1alpha, MIP-1beta and fractalkine are also thought to be involved in the associated inflammatory response. There have been a number of studies in recent years investigating cytokine profiles in different forms of uveitis with a view to determining what cytokines are important in the inflamed eye. This review attempts to present the current state of knowledge from in vitro and in vivo research on the inflammatory cytokines in intraocular inflammatory diseases.

Prevalence and levels of serum antibodies to gram negative microorganisms in Turkish patients with HLA-B27 positive acute anterior uveitis and controls

PURPOSE

Acute anterior uveitis (AAU), seronegative spondyloarthropathies such as ankylosing spondylitis and reactive arthritis form the group of "HLA-B27-associated diseases." The aim of this study was to analyze the prevalence and levels of serum antibodies against gram negative bacteria in Turkish patients with AAU.

METHODS

Twenty-five patients each with previously diagnosed HLA-B27 positive and negative AAU and 25 age-and sex-matched healthy control subjects were included in the study. Serum IgM, IgG and IgA antibodies to Yersiniae enterocolitica, Campylobacter jejuni and Chlamydia trachomatis were measured using enzyme linked immunosorbent assay (ELISA). Categorical data were analyzed by chi-square test. Serum levels were analyzed using the Kruskal-Wallis test.

RESULTS

The prevalence of serum IgM, IgG and IgA antibodies did not differ significantly between the HLA-B27 positive AAU, HLA-B27 negative AAU and control groups with the exception of serum IgA antibodies against Yersiniae enterocolitica. IgA antibody against Yersiniae enterocolitica was found to be more frequently positive in the control group. Comparison of serum IgM, IgG and IgA antibody levels did not significantly differ between three groups.

CONCLUSIONS

Serum antibody positivity against Yersiniae enterocolitica, Campylobacter jejuni and Chlamydia trachomatis is not frequent in the HLA-B27 positive and negative AAU patients. Serum levels of IgM, IgG, and IgA antibodies also did not show significant difference between three groups. No association between these microorganisms and the etiology of AAU was evident.

Acute anterior uveitis and HLA-B27

Acute anterior uveitis is the most common form of uveitis. HLA-B27-associated acute anterior uveitis is a distinct clinical entity that has wide-ranging medical significance due to its ocular, systemic, immunologic, and genetic features. The association between HLA-B27 and the spectrum of HLA-B27-associated inflammatory diseases remains one of the strongest HLA-disease associations known to date. This review examines acute anterior uveitis with particular focus on HLA-B27-associated acute anterior uveitis, including the epidemiology, immunopathology, association with HLA-B27 and its subtypes, clinical features, complications, prognosis, and potential new therapies such as anti-TNFalpha therapy and oral HLA-B27-peptide tolerance. There have been substantial recent advances in both clinical and basic scientific research in this field, including studies of the various animal models of acute anterior uveitis and the HLA-B27 transgenic animals, and these are summarized in this review. To the ophthalmologist, HLA-B27-associated acute anterior uveitis is an important clinical entity that is common, afflicts relatively young patients in their most productive years, and is associated with significant ocular morbidity due to its typically recurrent attacks of inflammation and its potentially vision-threatening ocular complications. Furthermore, to the ophthalmologist and the internist, HLA-B27-associated acute anterior uveitis is also of systemic importance due to its significant association with extraocular inflammatory diseases.

A locus on chromosome 9p predisposes to a specific disease manifestation, acute anterior uveitis, in ankylosing spondylitis, a genetically complex, multisystem, inflammatory disease

OBJECTIVE

Uveitis or intraocular inflammation is a major cause of visual loss. Acute anterior uveitis (AAU) affects approximately 40% of patients with ankylosing spondylitis (AS) but also affects patients with no evidence of spondylarthritis. We sought to determine whether a unique genetic region could be implicated in a specific manifestation-AAU-of a multisystem, inflammatory, genetically complex disease, AS.

METHODS

Individuals from families multiplex for AAU were genotyped at 400 markers representing the ABI PRISM linkage map MD-10, and at the HLA-B, DRB1, DQA1, DQB1, and DPB1 alleles. Among the family members with AAU, 76 affected sibpairs were analyzed (6 without concomitant AS, 12 discordant for AS, and 58 concordant for AS). Two-point and multipoint nonparametric linkage analyses were performed, and 1-parameter allele-sharing model logarithm of odds (LOD) scores were determined.

RESULTS

As previously reported for AS, linkage at the major histocompatibility complex region (chromosome 6p21) was evident, exhibiting the highest multipoint LOD score (4.96 at marker HLA-B). Strong linkage was seen at a region on chromosome 9p21-9p24, with a LOD score of 3.72 at marker D9S157. When compared with a companion cohort of AS families, the linkage at this region was found in association with AAU but not with AS. A third region on chromosome 1q23-1q31 was observed to have suggestive linkage (LOD 2.05 at marker D1S238), which overlaps with a region associated with AS.

CONCLUSION

This is the first study in which a genetic region for AAU has been identified by genome-wide scan. Even though AS was highly prevalent in this cohort of families, a locus at chromosome 9p21-9p24 was identified that uniquely associates with AAU. Identifying the genetic perturbation at this region may advance our understanding of the mechanisms involved in tissue-specific pathology of complex inflammatory diseases.

Bartonella henselae associated uveitis and HLA-B27

AIM

To investigate the frequency of HLA-B27 in patients with presumed Bartonella henselae associated uveitis and to describe the clinical characteristics of HLA-B27 positive patients with uveitis and presumed ocular bartonellosis (POB).

METHODS

The diagnosis of POB was considered in 19 patients with unexplained uveitis (except for the HLA-B27 association) and high positive IgG (titre >/=1:900) and/or IgM (titre >/=1:250) antibodies against B henselae. In addition to B henselae serology and HLA-B27 typing, all patients underwent an extensive standard diagnostic screening procedure for uveitis and in all cases the results were within the normal limits. The control group consisted of 25 consecutive patients with panuveitis and negative B henselae serology.

RESULTS

HLA-B27 was positive in six of the 19 patients (32%) with POB in contrast to the 4% frequency of HLA-B27 in the control group (p=0.03) and 8% prevalence of HLA-B27 in the Dutch population (p=0.003). At the time of positive Bartonella serological testing five of six HLA-B27 positive patients with POB had severe posterior segment involvement with papillitis, macular oedema, and vitreitis. The duration of intraocular inflammatory activity was more than 6 months in five HLA-B27 positive patients. Although four of the six HLA-B27 positive patients had previous recurrent attacks of acute anterior uveitis, the clinical presentation at the time of positive Bartonella serology differed, as illustrated by the involvement of the posterior segment and chronic course of the ocular disease.

CONCLUSIONS

The frequency of HLA-B27 in patients with uveitis and serological characteristics of acute infection with B henselae is higher than in the general Dutch population. The findings of this study also suggest a relation between infection with Bartonella species and HLA-B27.

Ciprofloxacin treatment does not influence course or relapse rate of reactive arthritis and anterior uveitis

OBJECTIVE

To assess the efficacy of ciprofloxacin in the treatment of reactive arthritis (ReA) and anterior uveitis (AU) in a double-blind, randomized, placebo-controlled trial.

METHODS

Seventy-two patients participated in this study, 56 with ReA and 42 with AU (26 patients had both ReA and AU). Ciprofloxacin (750 mg twice a day) was administered for 12 months with a 12-month followup. End points of the study included time to disease relapse and measures of disease severity.

RESULTS

There was no difference between groups in time to disease relapse, joint inflammation, number of joints and enthesis involved in patients with ReA, or signs and symptoms of AU.

CONCLUSION

Long-term treatment of ReA and AU with ciprofloxacin made no statistically significant difference to the natural history of these diseases or their severity.

Experimental melanin-induced uveitis in the Fischer 344 rat is inhibited by anti-CD4 monoclonal antibody, but not by mannose-6-phosphate

Experimental melanin-induced uveitis (EMIU) is a rodent model of acute anterior uveitis which was described in 1993. We investigated strain susceptibility, and age and gender characteristics of the model, undertook histological and immunohistochemical studies to investigate underlying cellular mechanisms, and examined several treatment options. Rats were immunized with bovine ocular melanin (250 microg), and disease was followed by slit lamp examination. Lewis, Fischer 344 and Porton rats were found to be susceptible to EMIU, whereas Wistar-Furth, DA, and Hooded Wistar strains were resistant. EMIU was neither age- nor gender-dependent. In Fischer 344 rats, EMIU was characterized clinically by florid anterior segment inflammation. Histopathological findings included infiltration of ciliary body and iris with mononuclear cells and neutrophils. Both CD4+ and CD8+ T lymphocytes were prominent. Rats were then treated with intraperitoneal injections of anti-CD4, anti-CD8 or irrelevant isotype-matched MoAb on days -3, 0, 3, 6 and 9 with respect to melanin immunization. Incidence of uveitis was significantly reduced in rats treated with a non-depleting cocktail of anti-CD4 MoAbs (P = 0.007), whereas a depleting anti-CD8 antibody had no effect on the disease. Mannose-6-phosphate inhibits lymphocyte migration in some models of T cell-mediated inflammation. This simple sugar was administered to additional rats via intraperitoneal osmotic pumps for 14 days following disease induction, but did not influence the uveitis. We conclude that EMIU is controlled by CD4+ T cells, and disease may be abrogated by treatment with anti-CD4 MoAbs.

Basic pathogenic mechanisms operating in experimental models of acute anterior uveitis

Acute anterior uveitis is a recurrent inflammatory disease of the eye that occurs commonly, is distressing for the patient, and may have potentially blinding sequelae. The pathogenesis of the disease is poorly understood, and anti-inflammatory treatment is consequently non-specific and may be associated with significant complications. Animal models are a possible key to a better understanding of this disease. In one model, rats and mice develop a relatively short-lived anterior uveal inflammation almost immediately after systemic injection of bacterial endotoxin. Accumulating evidence suggests that cytokine production by resident uveal macrophages initiates endotoxin-induced uveitis which is characterized by an infiltration of neutrophils and mononuclear cells. A second model displays features in keeping with a delayed-type hypersensitivity immune response. Experimental melanin-induced uveitis is an acute recurrent uveitis with delayed onset but extended duration, observed when rats are immunized with bovine ocular melanin. Both animal models have clinical features in common with acute anterior uveitis, although experimental melanin-induced uveitis appears to mimic the human disease more closely. Novel treatment options to target implicated inflammatory cells and molecules are currently under consideration.

TAP polymorphism is not associated with ankylosing spondylitis and complications with acute anterior uveitis in HLA-B27-positive Japanese

HLA-B27 is associated with the etiology of ankylosing spondylitis (AS) and acute anterior uveitis (AAU). Transporter associated with antigen processing (TAP) 1 and TAP2 polymorphism influences the range of peptide presented by HLA class I molecules. In this report, contribution of TAP polymorphism to the susceptibility to AS and AAU was studied in HLA-B27-positive Japanese individuals. Patients were classified into three groups: 16 AS patients, 14 AAU patients and 22 patients with both AS and AAU. Twelve HLA-B27-positive healthy individuals were included as a control. TAP polymorphism was detected by PCR-RFLP methods. Significant differences in frequencies of TAP1 alleles were not found between patient groups. None of the TAP2 frequencies showed increased or decreased frequencies compared with HLA-B27-positive healthy controls. In comparison with a random Japanese control, TAP2D allele frequency was significantly increased in the AAU group, but failed to reach a significant level in a group consisting of the AAU-only patients and the patients with both AS and AAU. All of the patient groups were noted to have a significantly increased prevalence of the TAP2H allele as compared to random controls; however, the higher frequency of this allele was detected in HLA-B27 healthy controls as well. These observations suggest a linkage disequilibrium between TAP2D, TAP2H and HLA-B27 in Japanese.

Diagnosing the systemic associations of anterior uveitis

Up to one-half of patients with anterior uveitis suffer from related systemic diseases. The common associations are the seronegative arthropathies and, in children, juvenile chronic arthritis. Anterior uveitis may also occur in the context of sarcoidosis or Behçet's disease. Syphilis and tuberculosis remain a significant problem for specific populations and may be the cause of anterior uveitis in these groups. By thorough clinical history and the correct selection and interpretation of simple investigations, it is generally possible for the ophthalmologist to make or exclude a systemic diagnosis, predict the ocular prognosis and direct selected patients to the appropriate physician. Diseases that threaten the patient's wellbeing must certainly be recognized. In the present review we present a method for identifying the systemic associations of anterior uveitis.

Infectious diseases and immunity: special reference to major histocompatibility complex

Human leukocyte antigens (HLAs) are an inherent system of alloantigens, which are the products of genes of the major histocompatibility complex (MHC). These genes span a region of approximately 4 centimorgans on the short arm of human chromosome 6 at band p 21.3 and encode the HLA class I and class II antigens, which play a central role in cell-to-cell interaction in the immune system. These antigens interact with the antigen-specific cell surface receptors of T lymphocytes (TCR) thus causing activation of the lymphocytes and the resulting immune response. Class I antigens restrict cytotoxic T-cell (CD8+) function thus killing viral infected targets, while class II antigens are involved in presentation of exogenous antigens to T-helper cells (CD4+) by antigen presenting cells (APC). The APC processes the antigens, and the immunogenic peptide is then presented at the cell surface along with the MHC molecule for recognition by the TCR. Since the MHC molecules play a central role in regulating the immune response, they may have an important role in controlling resistance and susceptibility to diseases. In this review we have highlighted studies conducted to look for an association between HLA and infectious diseases; such studies have had a variable degree of success because the pathogenesis of different diseases varies widely, and most diseases have a polygenic etiology.

Increased matrix metalloproteinases in the aqueous humor of patients and experimental animals with uveitis

PURPOSE

Matrix metalloproteinases (MMPs) play a major role in connective tissue remodelling, wound healing and embryogenesis. They have also been implicated in pathological tissue degradation in diseases such as rheumatoid arthritis (RA), osteoarthritis (OA), and tumor invasion. The aim of this study was to define the potential role of MMPs in the inflammatory process of uveitis by identifying these proteases in the aqueous humor (AH) of patients with uveitis and in rabbits with endotoxin-induced uveitis (EIU).

METHODS

Aqueous humor samples from 6 patients with uveitis and 5 control patients who had undergone elective cataract surgery were examined. The profile of MMPs in the AH of experimentally-induced acute anterior uveitis in rabbits was also assessed. Western blot analysis and SDS-PAGE substrate zymography were used to detect metalloenzymes and their natural inhibitor, tissue inhibitor of metalloproteinase (TIMP-1) in aqueous samples.

RESULTS

Aqueous humor from all patients contained interstitial collagenase (MMP-1), stromelysin (MMP-3), gelatinase B (MMP-9) and TIMP-1. Although the amount of MMPs varied considerably, TIMP-1 levels remained unchanged in the aqueous of uveitis patients. Using substrate gel zymography, we were able to reveal several gelatinolytic bands, including one major band at approximately 92-kDa whose activity differed between uveitis and cataract AH. The gelatinase activity found in human AH samples was shown to be inhibited by 10 mM EDTA and activated in vitro by APMA, indicating that these enzymes were indeed of the metalloproteinase class. Aqueous humor samples from the rabbit EIU model revealed a 100-kDa molecular weight species likely to correspond to gelatinase B. This gelatinolytic activity was maximal at 6 hours after the lipopolysaccharide (LPS) injection, declined at 12 and 24 hours post LPS, and was absent at later time points. The induction of gelatinase activity in rabbit AH preceded the increase in cell number during the inflammatory process in the anterior chamber.

CONCLUSIONS

Metalloproteinases found in normal human AH may participate in physiological turnover of extracellular matrix in the eye. Elevated levels of MMPs were found in the AH of patients with uveal inflammation and animals with LPS-induced uveitis, where they are likely to be critical to tissue destructive and repair processes. It is likely that pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha), which are known modulators of MMPs, induce their secretion in acute anterior uveitis.

Independent Associations of the HLA-B27 Antigen and the Complement Haplotype SC21 in Chronic Anterior Uveitis

There is evidence of an association between major histocompatibility complex (MHC) genes and acute anterior uveitis; here the authors report the frequency of class I and class III MHC phenotypes in 32 Mexican mestizo patients with chronic anterior uveitis and compared them to those present in 100 ethnically matched healthy controls. Results showed in patients statistically significant increased frequencies of HLA-B(27) antigen (pC=0.02, OR=6.33, 95+ CI:1.63-26.47) and the complotype SC(21) (pC=0.04, OR=4.5, 95+ CI:1.40-14.67); the authors found a decreased frequency of HLA-B(35) (p=0.006, OR=0.10, 95+ CI: 0.00-0.65) as compared to normal controls. None of the individuals bearing the SC(21) complotype were positive for HLA-B(27), suggesting independent roles of the class I and class III antigens in the genetic susceptibility to chronic anterior uveitis.

Acute anterior uveitis: clinical and experimental aspects

Acute anterior uveitis (AAU) or iritis is an inflammatory disorder of the anterior structures of the eye that may be associated with a number of disease entities. A significant proportion of patients will have no evidence of an underlying disorder and are labeled as idiopathic. Within this group approximately 50% will possess the human leukocyte antigen, HLA-B27, and some will have an associated spondyloarthropathy such as ankylosing spondylitis or Reiter's syndrome. Nevertheless, a number of HLA-B27-positive patients have no apparent underlying rheumatic disorder. The potential interplay of HLA-B27 and certain infective agents in the pathogenesis of AAU is discussed with particular reference to Yersinia species. Presentation of a uveitogenic peptide, similar to the arthritogenic peptide model in spondyloarthropathies, may be a mechanism involved in the development of AAU. Experimental models in animals have increased our understanding of the roles of retinal proteins and bacterial peptides, as well as T cells and cytokines, in the pathogenesis of uveitis. As in animal models of arthritis, certain retinal peptides (in conjunction with adjuvant therapy) can induce uveitis in animals. The treatment of isolated AAU usually involves topical medication and the prognosis is good. Occasional cases, especially those associated with systemic disorders, may require the addition of systemic corticosteroids or other immunosuppressive medications.