Frequent immune response to a melanocyte specific protein KU-MEL-1 in patients with Vogt-Koyanagi-Harada disease

[Recurrent chronic Vogt-Koyanagi-Harada syndrome or sarcoidosis? A Gloomy diagnosis]

Background

Vogt-Koyanagi-Harada syndrome (VKH) is a systemic disease that affects organs profuse in melanocytes, presenting with a chronic and diffuse bilateral granulomatous panuveitis, as well as neurological, auditory, and cutaneous manifestations. In this article, a systematic approach is presented for the diagnostic management of VKH syndrome, considering relevant diagnostic possibilities to rule out other entities that manifest similar symptoms.

Clinical case

71-year-old man with a long-standing history of vitiligo, who experienced visual loss in his right eye 6 months before his admission, along with bilateral hearing loss predominantly in the right ear. During his hospitalization, he presented with chronic headache, fever, and significant involuntary weight loss. Ophthalmological examination revealed that his right eye only perceived light and had hyperemic bulbar conjunctiva, while the left eye had a visual acuity of 20/200. The right fundus had scattered pigmentation, while the left had an edematous optic disc and right optic atrophy.

Conclusions

The diagnosis of VKH syndrome is established by the presence of the 5 diagnostic criteria for complete disease, including retinal depigmentation, neurological alterations, and dermatological manifestations. Since patients can present with a wide variety of symptoms, initial differential diagnosis should be considered, which represents a diagnostic challenge.

Genome-wide association study for systemic lupus erythematosus in an egyptian population

Systemic lupus erythematosus (SLE) susceptibility has a strong genetic component. Genome-wide association studies (GWAS) across trans-ancestral populations show both common and distinct genetic variants of susceptibility across European and Asian ancestries, while many other ethnic populations remain underexplored. We conducted the first SLE GWAS on Egyptians-an admixed North African/Middle Eastern population-using 537 patients and 883 controls. To identify novel susceptibility loci and replicate previously known loci, we performed imputation-based association analysis with 6,382,276 SNPs while accounting for individual admixture. We validated the association analysis using adaptive permutation tests (n = 109). We identified a novel genome-wide significant locus near IRS1/miR-5702 (Pcorrected = 1.98 × 10-8) and eight novel suggestive loci (Pcorrected < 1.0 × 10-5). We also replicated (Pperm < 0.01) 97 previously known loci with at least one associated nearby SNP, with ITGAM, DEF6-PPARD and IRF5 the top three replicated loci. SNPs correlated (r 2 > 0.8) with lead SNPs from four suggestive loci (ARMC9, DIAPH3, IFLDT1, and ENTPD3) were associated with differential gene expression (3.5 × 10-95 < p < 1.0 × 10-2) across diverse tissues. These loci are involved in cellular proliferation and invasion-pathways prominent in lupus and nephritis. Our study highlights the utility of GWAS in an admixed Egyptian population for delineating new genetic associations and for understanding SLE pathogenesis.

Mucosal-associated invariant T cells have therapeutic potential against ocular autoimmunity

Autoimmune uveitis is a sight-threatening disease induced by pathogenic T cells that recognize retinal antigens; it is observed in disorders including Vogt-Koyanagi-Harada disease (VKH). The roles of specific T cell subsets and their therapeutic potential against autoimmune uveitis are not fully understood. Here we conducted multi-parametric single-cell protein quantification which shows that the frequency of CD161^highTRAV1-2⁺ mucosal-associated invariant T (MAIT) cells that recognize vitamin B2 metabolite-based antigens is decreased in relapsing VKH patients compared to individuals without active ocular inflammation. An experimental autoimmune uveitis (EAU) mouse model revealed that genetic depletion of MAIT cells reduced the expression of interleukin (Il) 22 and exacerbated retinal pathology. Reduced IL-22 levels were commonly observed in patients with relapsing VKH compared to individuals without active ocular inflammation. Both mouse and human MAIT cells produced IL-22 upon stimulation with their antigenic metabolite in vitro. An intravitreal administration of the antigenic metabolite into EAU mice induced retinal MAIT cell expansion and enhanced the expressions of Il22, as well as its downstream genes related to anti-inflammatory and neuroprotective effects, leading to an improvement in both retinal pathology and visual function. Taken together, we demonstrate that a metabolite-driven approach targeting MAIT cells has therapeutic potential against autoimmune uveitis.

miRNA Landscape in Pathogenesis and Treatment of Vogt-Koyanagi-Harada Disease

miRNAs, one of the members of the noncoding RNA family, are regulators of gene expression in inflammatory and autoimmune diseases. Changes in miRNA pool expression have been associated with differentiation of CD4⁺ T cells toward an inflammatory phenotype and with loss of self-tolerance in autoimmune diseases. Vogt–Koyanagi–Harada (VKH) disease is a chronic multisystemic pathology, affecting the uvea, inner ear, central nervous system, and skin. Several lines of evidence support an autoimmune etiology for VKH, with loss of tolerance against retinal pigmented epithelium-related self-antigens. This deleterious reaction is characterized by exacerbated inflammation, due to an aberrant T_H1 and T_H17 polarization and secretion of their proinflammatory hallmark cytokines interleukin 6 (IL-6), IL-17, interferon γ, and tumor necrosis factor α, and an impaired CD4⁺ CD25^high FoxP3⁺ regulatory T cell function. To restrain inflammation, VKH is pharmacologically treated with corticosteroids and immunosuppressive drugs as first and second line of therapy, respectively. Changes in the expression of miRNAs related to immunoregulatory pathways have been associated with VKH development, whereas some genetic variants of miRNAs have been found to be risk modifiers of VKH. Furthermore, the drugs commonly used in VKH treatment have great influence on miRNA expression, including those miRNAs associated to VKH disease. This relationship between response to therapy and miRNA regulation suggests that these small noncoding molecules might be therapeutic targets for the development of more effective and specific pharmacological therapy for VKH. In this review, we discuss the latest evidence regarding regulation and alteration of miRNA associated with VKH disease and its treatment.

Vogt-Koyanagi-Harada is a Curable Autoimmune Disease: Early Diagnosis and Immediate Dual Steroidal and Non-Steroidal Immunosuppression are Crucial Prerequisites

Purpose:

It is crucial to subdivide Vogt–Koyanagi–Harada (VKH) disease into two subentities, initial-onset disease versus chronically evolving disease. For early diagnosis and precise follow-up of VKH choroiditis, the “Revised criteria for VKH” are no more sufficient for the appraisal of VKH and new biomarkers for disease activity are needed. It has been shown that, if initial-onset disease is treated promptly within the “therapeutic window of opportunity” and long enough with dual steroidal and non-steroidal immunosuppression, the disease can be cured in a large proportion of cases, an approach still contested. The proportion of chronic evolution and/or sunset-glow fundus (SGF) following steroidal monotherapy versus dual steroidal and non-steroidal immunosuppression was compared.

Methods:

A literature search was performed, identifying studies on initial-onset VKH treated either by steroidal monotherapy or dual immunosuppression. Evolution toward chronicity and/or SGF was compared in both groups.

Results:

Twenty studies were identified with reported long-term outcomes. In 16 studies, 802 patients received steroidal monotherapy, while in 4 studies, 172 patients received dual steroidal and non-steroidal immunosuppression. Chronic evolution and SGF occurred, respectively, in 44% and 59% in the corticosteroid-alone group versus 2.3% and 17.5% in the dual therapy group with no chronic evolution in three studies and no SGF in two studies.

Conclusions:

Chronic evolution and SGF are significantly less frequent in initial-onset VKH when treated with immediate dual steroidal and non-steroidal immunosuppression with a high proportion of healed cases. This combined approach seems recommended in the management of initial-onset VKH disease.

HLA-A29 and Birdshot Uveitis: Further Down the Rabbit Hole

HLA class I alleles constitute established risk factors for non-infectious uveitis and preemptive genotyping of HLA class I alleles is standard practice in the diagnostic work-up. The HLA-A29 serotype is indispensable to Birdshot Uveitis (BU) and renders this enigmatic eye condition a unique model to better understand how the antigen processing and presentation machinery contributes to non-infectious uveitis or chronic inflammatory conditions in general. This review will discuss salient points regarding the protein structure of HLA-A29 and how key amino acid positions impact the peptide binding preference and interaction with T cells. We discuss to what extent the risk genes ERAP1 and ERAP2 uniquely affect HLA-A29 and how the discovery of a HLA-A29-specific submotif may impact autoantigen discovery. We further provide a compelling argument to solve the long-standing question why BU only affects HLA-A29-positive individuals from Western-European ancestry by exploiting data from the 1000 Genomes Project. We combine novel insights from structural and immunopeptidomic studies and discuss the functional implications of genetic associations across the HLA class I antigen presentation pathway to refine the etiological basis of Birdshot Uveitis.

Bilateral Cochlear Implantation in Vogt-Koyanagi-Harada Syndrome: A Case Report

OBJECTIVE

To evaluate cochlear implantation in Vogt-Koyanagi-Harada syndrome with regard to surgical difficulties and hearing outcomes.

PATIENTS

Single case report.

INTERVENTION(S)

Therapeutic complete electrode insertion during surgery despite evident intra-cochlear fibrosis.

MAIN OUTCOME MEASURE(S)

Postoperative speech audiometry, categories of auditory performance, and speech intelligibility rating.

RESULTS

Vogt-Koyanagi-Harada syndrome is a multisystem autoimmune disease that affects tissues containing melanin. It is characterized by bilateral uveitis with auditory, vestibular, and dermatologic manifestations. Standard treatment comprises aggressive administration of systemic corticosteroids.This report describes the use of bilateral cochlear implants in a 30-year-old Saudi woman who presented with uveitis and was diagnosed with Vogt-Koyanagi-Harada syndrome. She had progressive hearing loss in both ears and experienced minimal improvement with hearing aids. The patient underwent sequential cochlear implantation, which was challenging because it was difficult to insert the electrode in the right ear due to intra-cochlear fibrosis. After more than 5 years of follow-up, she has good hearing in both ears, despite the advancement of ocular disease and recurring visual complaints.

CONCLUSION

This study suggests that patients with Vogt-Koyanagi-Harada syndrome could develop intra-cochlear fibrosis during cochlear implantation due to the autoimmune nature of disease. Moreover, cochlear implantation becomes more difficult with disease advancement. Therefore, it is essential that healthcare professionals consider early detection and prompt treatment of hearing loss in patients with this syndrome.

Association Study of ARMC9 Gene Variants with Vogt-Koyanagi-Harada Disease in Japanese Patients

Purpose: To investigate whether variants in the ARMC9 gene encoding KU-MEL-1 are associated with Vogt-Koyanagi-Harada (VKH) disease in a Japanese population. Methods: We recruited 380 Japanese patients with VKH disease and 744 Japanese healthy controls to genotype seven single-nucleotide polymorphisms (SNPs) in ARMC9. We also performed imputation analysis of the ARMC9 region and 195 imputed SNPs were included in the statistical analysis. Results: We observed an increased frequency of the A allele of rs28690417 in patients compared with controls (P = 0.0097, odds ratio (OR) = 1.46). The A allele had a dominant effect on VKH disease risk (P = 0.011, OR = 1.51). However, these significant differences disappeared after Bonferroni correction (corrected P > 0.05). The remaining 201 SNPs did not show any significant association with disease risk. Conclusions: Our study suggests that ARMC9 variants do not play a critical role in the development of VKH disease.

Vogt-Koyanagi-Harada disease: Novel insights into pathophysiology, diagnosis and treatment

Vogt-Koyanagi-Harada (VKH) disease is one of the major vision-threatening diseases in certain populations, such as Asians, native Americans, Hispanics and Middle Easterners. It is characterized by bilateral uveitis that is frequently associated with neurological (meningeal), auditory, and integumentary manifestations. Although the etiology and pathogenesis of VKH disease need to be further elucidated, it is widely accepted that the clinical manifestations are caused by an autoimmune response directed against melanin associated antigens in the target organs, i.e. the eye, inner ear, meninges and skin. In the past decades, accumulating evidence has shown that genetic factors, including VKH disease specific risk factors (HLA-DR4) and general risk factors for immune mediated diseases (IL-23R), dysfunction of immune responses, including the innate and adaptive immune system and environmental triggering factors are all involved in the development of VKH disease. Clinically, the criteria of diagnosis for VKH disease have been further improved by the employment of novel imaging techniques for the eye. For the treatment, early and adequate corticosteroids are still the mainstream regime for the disease. However, immunosuppressive and biological agents have shown benefit for the treatment of VKH disease, especially for those patients not responding to corticosteroids. This review is focused on our current knowledge of VKH disease, especially for the diagnosis, pathogenesis (genetic factors and immune mechanisms), ancillary tests and treatment. A better understanding of the role of microbiome composition, genetic basis and ongoing immune processes along with the development of novel biomarkers and objective quantitative assays to monitor intraocular inflammation are needed to improve current management of VKH patients.

Influence of molecular genetics in Vogt-Koyanagi-Harada disease

Vogt-Koyanagi-Harada (VKH) disease is a systemic autoimmune disorder against melanocytes. Recent studies have identified multiple genetic factors that might be associated with the pathogenesis of VKH disease. We performed an electronic database search of PubMed, MEDLINE, and EMBASE, and all relevant papers published up to 13 June 2014 were reviewed. A total of 1,031 publications including articles relevant to the genetics of VKH disease and the references of these articles were reviewed. The review identified a number of genetic factors which might be involved in the pathogenesis of VKH disease, some of which may alter the clinical course of VKH disease. Genes which might be involved in the pathogenesis of VKH disease included genes expressing HLA, complement factor H, interleukins, cytotoxic T-lymphocyte antigen 4 (CTLA-4), killer cell immunoglobulin-like receptors (KIR), programmed cell death 1 (PDCD1), protein tyrosine phosphatase non-receptor 22 (PTPN22), osteopontin, tumor necrosis factor alpha-induced protein 3 (TNFAIP3), macrophage migration inhibitory factor (MIF), and other immune response genes. Further studies to explore the correlation among different genotypes and phenotypes of VKH disease will be useful to shed light on the pathogenesis of uveitis in VKH disease and may facilitate the development of new treatment modalities of uveitis in VKH disease.

Absence of recognition of common melanocytic antigens by T cells isolated from the cerebrospinal fluid of a Vogt-Koyanagi-Harada patient

PURPOSE

Vogt-Koyanagi-Harada (VKH) syndrome is an autoimmune disease characterized by inaugural uveomeningitidis and hearing loss and at late stages a depigmentation in eyes and skin. Melanocytes are the cells common to the four affected tissues, namely eye, brain, inner ear, and skin. Melanocytes are therefore considered as the source of self-antigens. The melanocytic proteins tyrosinase-related protein-1 (TRP1), TRP2, tyrosinase, and gp100 have been proposed as the proteins targeted by autoreactive T cells from VKH patients bearing human leukocyte antigen (HLA)-DRB1*04:05, the HLA allele classically associated with VKH disease. The objective of this work was to determine the antigens recognized by a large number of potentially autoreactive CD4 T lymphocytes obtained from the cerebrospinal fluid of one VKH patient who did not express HLA-DRB1*04:05.

METHODS

T cells were isolated from the cerebrospinal fluid of a newly diagnosed HLA-DRB1*14:01,*15:03;-DPB1*01:01,*04:02 patient in the acute phase of the VKH disease and cloned by limiting dilution. Each of the 107 T cell clones, of which 90% were CD4(+), was tested for its ability to secrete cytokines upon contact with autologous antigen-presenting cells loaded with either of the melanocytic proteins TRP1, TRP2, tyrosinase, gp100, Melan-A and KU-MEL-1. The sensitivity of our recombinant bacteria-based approach was validated with a CD4 T cell clone with known antigen specificity. The ability of each of the 107 clones to secrete cytokines upon nonspecific stimulation was verified.

RESULTS

None of the 107 T cell clones was able to secrete tumor necrosis factor-α, interferon-γ, interleukin (IL)-5, or IL-17 upon contact with autologous B cells loaded with any of the six common melanocytic proteins. Nine clones secreted high-level IL-17 upon stimulation with beads coated with antibodies.

CONCLUSIONS

The self-antigens that triggered the VKH disease in this patient probably derive from proteins other than the six melanocytic proteins mentioned above. Further study of antigens that are recognized by potential autoreactive T cells from VKH patients is likely to benefit from testing a broader set of melanocytic proteins.

Genetic risk factors for insidious equine recurrent uveitis in Appaloosa horses

Appaloosa horses are predisposed to equine recurrent uveitis (ERU), an immune-mediated disease characterized by recurring inflammation of the uveal tract in the eye, which is the leading cause of blindness in horses. Nine genetic markers from the ECA1 region responsible for the spotted coat color of Appaloosa horses, and 13 microsatellites spanning the equine major histocompatibility complex (ELA) on ECA20, were evaluated for association with ERU in a group of 53 Appaloosa ERU cases and 43 healthy Appaloosa controls. Three markers were significantly associated (corrected P-value <0.05): a SNP within intron 11 of the TRPM1 gene on ECA1, an ELA class I microsatellite located near the boundary of the ELA class III and class II regions and an ELA class II microsatellite located in intron 1 of the DRA gene. Association between these three genetic markers and the ERU phenotype was confirmed in a second population of 24 insidious ERU Appaloosa cases and 16 Appaloosa controls. The relative odds of being an ERU case for each allele of these three markers were estimated by fitting a logistic mixed model with each of the associated markers independently and with all three markers simultaneously. The risk model using these markers classified ~80% of ERU cases and 75% of controls in the second population as moderate or high risk, and low risk respectively. Future studies to refine the associations at ECA1 and ELA loci and identify functional variants could uncover alleles conferring susceptibility to ERU in Appaloosa horses.

Vogt-Koyanagi-Harada syndrome

OBJECTIVES

The objectives of this study are to review our current knowledge of the aetiopathogenesis of Vogt-Koyanagi-Harada syndrome, including viral infection, genetic factors and immunomediated mechanisms, and to discuss pathogenesis and its relevance to pharmacotherapy.

SYSTEMATIC REVIEW METHODOLOGY

Relevant publications from 1965 to 2012 on the aetiopathogenesis and pharmacotherapy of VKHS were analysed.

RESULTS AND CONCLUSION

Vogt-Koyanagi-Harada syndrome (VKHS) is a rare multisystemic autoimmune disease that affects tissues containing melanin, including the eye, inner ear, meninges, and skin. The disease is characterised by bilateral uveitis associated with a varying constellation of auditory, neurological and cutaneous manifestations. The disease occurs more frequently among people with darker skin pigmentation. Asians, Native Americans, and Hispanics are most frequently affected. It predominates in patients aged between 20 and 50years, and females are affected more frequently, with a female:male ratio of 2:1. The classic clinical course is characterised by bilateral panuveitis, hypoacusis, and meningitis, in addition to cutaneous involvement with poliosis, vitiligo, and alopecia. Although the exact cause of VKH disease remains unknown, it is thought to be a T-cell-mediated autoimmune process directed against melanocytes. VKHS classically begins with vague systemic symptoms suggestive of a viral infection, although a clear association between a specific viral agent and the disease has not been established. Genetic factors may play an important role in the loss of self-tolerance in VKHS. The HLA-DRB1*0405 allele is the main susceptibility allele for VKHS. Early and aggressive systemic corticosteroids are still the primary initial therapy for VKHS. Ocular complications may require an intravitreous injection of corticosteroids. Despite proper treatment with steroids, a number of patients experience recurrent attacks or steroid-associated complications. Thus, non steroid immunomodulatory therapy (IMT) has become necessary for the treatment of VKHS.

Vogt-Koyanagi-Harada syndrome in a 6-year-old Hispanic boy

A 6-year-old Hispanic boy presented to the ophthalmology department with complaints of pain, photophobia, and blurry vision of both eyes. He was found to have bilateral granulomatous panuveitis, cataracts, and high intraocular pressures. He later developed multiple asymptomatic, ovoid, hypopigmented patches over the mid-lumbosacral back. Biopsy of lesional skin was significant for low melanocyte counts and a mild lymphocytic infiltrate. The patient was diagnosed with Vogt-Koyanagi-Harada syndrome (VKH). This article reviews the literature regarding the cutaneous presentation of VKH.

Updated assessment of the prevalence, spectrum and case definition of autoimmune disease

Autoimmune diseases are heterogeneous with regard to prevalence, manifestations, and pathogenesis. The classification of autoimmune diseases has varied over time. Here, we have compiled a comprehensive up-to-date list of the autoimmune diseases, and have reviewed published literature to estimate their prevalence. We identified 81 autoimmune diseases. The overall estimated prevalence is 4.5%, with 2.7% for males and 6.4% for females. For specific diseases, prevalence ranges from 1% to <1/10(6). Considering all diseases in the class, the most common mean age-of-onset was 40-50 years. This list of autoimmune diseases has also yielded information about autoantigens. Forty-five autoimmune diseases have been associated with well-defined autoantigens. Of the diseases with known autoantigens, 33.3% had highly repetitive sequences, 35.6% had coiled-coil arrangements and 57.8% were associated with cellular membranes, which means that based on these structural motifs alone, autoantigens do not appear to be a random sample of the human proteome. Finally, we identified 19 autoimmune diseases that phenocopy diseases arising from germline mutations in the corresponding autoantigen. Collectively, our findings lead to a tentative proposal for criteria for assigning autoimmune pathogenesis to a particular disease.

HLA-DRB1 among patients with Vogt-Koyanagi-Harada disease in Saudi Arabia

PURPOSE

Vogt-Koyanagi-Harada (VKH) disease is an immune-mediated disorder with autoimmune insult directed against antigens associated with melanocytes. The genetic predisposition among VKH has not been explored in Saudi Arabia. So, the purpose of this study was to investigate the association of human leukocyte antigen (HLA)-DRB1 alleles to VKH patients and to clarify the molecular genetic mechanism underlying the susceptibility or resistance to VKH disease.

METHODS

Genomic DNA from a total of 30 patients with VKH and 29 control subjects was extracted from peripheral blood, and HLA-DRB1 alleles were typed by polymerase chain reaction and sequence based typing (SBT).

RESULTS

We found a statistically significant difference in the prevalence of HLA-DRB1 *0405 between the VKH patients and control subjects (p<0.05). Eleven out of thirty (36.6%) patients with VKH had positive HLA-DRB1 *0405 compared to two out of twenty-nine (6.9%) control subjects. However, there were no statistically significant differences in the HLA-DRB1 alleles *01, *0101, *0102, *0301, *04, *0403, *0404, *0701, *1001, *1101, *1112, *1301, *1302, *1303, *1501, and *1502 between the VKH patients and controls.

CONCLUSIONS

Patients with VKH had significantly greater incidence of HLA-DRB1 *0405 when compared to age and sex-matched controls. Consequently, this finding suggests that HLA-DRB1 *0405 allele might play a role in the pathogenesis of VKH disease.

Vogt-koyanagi-harada syndrome

PURPOSE

Vogt-Koyanagi-Harada syndrome is a bilateral, chronic, diffuse granulomatous panuveitis frequently associated with neurological, auditory, and integumentary manifestations. It is also one of the most common forms of uveitis among pigmented races including Chinese patients.

METHODS

This article reviews the current developments of Vogt-Koyanagi-Harada syndrome, including epidemiology, etiology, clinical features, observational techniques, genetics, treatment, and prognosis.

RESULTS

Increasing reports have been published to describe the clinical features of Vogt-Koyanagi-Harada syndrome in various ethnic populations from different parts of the world. In spite of tremendous progress in laboratory and clinical research, the etiology of Vogt-Koyanagi-Harada syndrome is still not completely known. Numerous studies indicate an autoimmune nature for this disease. A recent study has shown that Th17, a new subset of T cell, plays an important role in the initiation and maintenance of this disease. Early and aggressive systemic corticosteroids are still the mainstay of initial therapy for Vogt-Koyanagi-Harada syndrome. However, nonsteroid immunomodulatory therapy, including cyclosporine, chlorambucil, cyclophosphamide, and azathioprine have brought out encouraging results. Improved visual outcomes in patients with Vogt-Koyanagi-Harada syndrome in recent years have been reported when compared with decades ago, presumably due to the more aggressive use of immunosuppressive agents.

CONCLUSION

Although the prognosis for VKH syndrome was greatly improved, future prospective, controlled, multi-center studies are needed to determine the optimal treatment regime for this disease. The IL17/23 pathway may provide a novel therapeutic target to control inflammation in VKH syndrome.