|Year : 2015 | Volume
| Issue : 13 | Page : 1743-1747
Variants of Interferon Regulatory Factor 5 are Associated with Neither Neuromyelitis Optica Nor Multiple Sclerosis in the Southeastern Han Chinese Population
Qi-Bing Liu1, Lei Wu2, Gui-Xian Zhao3, Ping-Ping Cai1, Zhen-Xin Li3, Zhi-Ying Wu4
1 Department of Neurology, Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350005, China
2 Department of Neurology, Research Center of Neurology in Second Affiliated Hospital, and The Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009, China
3 Department of Neurology, Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200040, China
4 Department of Neurology, Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350005; Department of Neurology, Research Center of Neurology in Second Affiliated Hospital, and The Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310009; Department of Neurology, Institute of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200040, China
|Date of Submission||08-Mar-2015|
|Date of Web Publication||25-Jun-2015|
Department of Neurology, Research Center of Neurology in Second Affiliated Hospital, and The Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, 88 Jiefang Road, Hangzhou, Zhejiang 310009
Source of Support: This work was supported by the grants from the National Natural Science Foundation of China (No. 81125009 and No. 30911120488). It was also supported by national key clinical specialty discipline construction program., Conflict of Interest: None
Background: Neuromyelitis optica (NMO) and multiple sclerosis (MS) are demyelinating disorders of the central nervous system. Interferon regulatory factor 5 (IRF5) is a common susceptibility gene to different autoimmune disorders. However, the association of IRF5 variants with NMO and MS patients has not been well studied. Therefore, we aimed to evaluate whether IRF5 variants were associated with NMO and MS in the Southeastern Han Chinese population.
Methods: Four single nucleotide polymorphisms (SNPs) were selected and genotyped by matrix-assisted laser desorption/ionization time of flight mass spectrometry in 111 NMO patients, 145 MS patients and 300 controls from Southeastern China.
Results: None of these 4 SNPs was associated with NMO or MS patients.
Conclusions: Our preliminary study indicates that genetic variants in IRF5 may affect neither NMO nor MS in the Southeastern Han Chinese population. Further studies with a large sample size and diverse ancestry populations are needed to clarify this issue.
Keywords: Association; Chinese; Interferon Regulatory Factor 5; Multiple Sclerosis; Neuromyelitis Optica
|How to cite this article:|
Liu QB, Wu L, Zhao GX, Cai PP, Li ZX, Wu ZY. Variants of Interferon Regulatory Factor 5 are Associated with Neither Neuromyelitis Optica Nor Multiple Sclerosis in the Southeastern Han Chinese Population. Chin Med J 2015;128:1743-7
|How to cite this URL:|
Liu QB, Wu L, Zhao GX, Cai PP, Li ZX, Wu ZY. Variants of Interferon Regulatory Factor 5 are Associated with Neither Neuromyelitis Optica Nor Multiple Sclerosis in the Southeastern Han Chinese Population. Chin Med J [serial online] 2015 [cited 2018 Jul 20];128:1743-7. Available from: http://www.cmj.org/text.asp?2015/128/13/1743/159347
| Introduction|| |
Neuromyelitis optica (NMO) is an idiopathic inflammatory demyelinating disorder of the central nervous system characterized by recurrent attacks of severe optic neuritis and myelitis, which is relatively common in Asian populations.  Serum immunoglobulin G (NMO), an autoantibody against aquaporin 4 (AQP4), has been shown to be a highly specific biomarker for NMO, distinguishing it from multiple sclerosis (MS).  Evidences suggest these diseases are caused by genetic and environmental factors. ,
The genetic component of MS is complex and a number of genes have been implicated in MS susceptibility. ,,, However, few comprehensive analysis of the association in NMO has been reported. A single nucleotide polymorphism (SNP) within the promoter of CYP7A1 encoding cytochrome P450 enzyme has been identified as a protective factor of NMO in a genome-wide association study (GWAS),  which was replicated in our previous study.  Also, the DPB1*0501 allele was associated with NMO in Japanese and Southern Han Chinese, , while the DRB1*03 allele was associated with NMO in Caucasians,  suggesting differences in genetic background. In addition, our recent study showed no association between non-MHC MS risk loci and NMO.  Thus, the genetic susceptibility of NMO is apparently different from MS.
The interferon regulatory factors (IRFs) play critical roles in cytokine signaling, cell growth and apoptosis, as well as the regulation of the immune response.  IRF5 is expressed mainly in dendritic cells, monocytes and B cells and has an important role in interferon production. , In addition, the B-cell-intrinsic role of IRF5 is important in promoting the inflammatory process and also in autoimmune pathology by increasing the expression of a kind of antibody isotype. 
However, the association of IRF5 variants with NMO and MS patients has not been well studied. Therefore, the aim of the present study was to evaluate whether IRF5 variants were associated with NMO and MS in the Southeastern Han Chinese population.
| Methods|| |
Between September 2008 to August 2012, 111 NMO patients were recruited according to the 2006 Wingerchuk criteria and 145 MS patients were recruited according to the revised McDonald criteria for MS. , All the patients underwent detailed neurological examinations, laboratory tests, and magnetic resonance imaging scans of the brain and/or spinal cord. The patients were followed up at regular intervals. All of the patients were Han Chinese from Southeastern China. In addition, 300 unrelated controls with no history of autoimmune diseases were matched for case ethnicity and region. The study protocol was approved by the local research ethics committees. A signed informed consent was obtained from each participant.
Detection of anti-against aquaporin 4 antibodies
Anti-AQP4 antibodies were tested with an indirect immunoﬂuorescence assay using HEK293 cells transfected with recombinant human AQP4 gene (Euroimmun, Lubeck, Germany) according to the instruction.  Each sample was measured at least twice, with the examiners blind to the origin of the specimens. Samples with twice positive results were deemed to be anti-AQP4 antibodies positive.
Genomic DNA was extracted from peripheral blood using a TIANamp Blood DNA kit (TIANGEN Biotech, Beijing, China). Four selected SNPs were genotyped using the Sequenom MassArray system. We used MassArray Assay Design 3.1 software (Sequenom, San Diego, USA) to design the polymerase chain reaction (PCR) primers used in the genotyping. The PCR and extension primers for these 4 SNPs are shown in the [Table 1]. Alleles were detected using a matrix-assisted laser desorption/ionization time of flight mass spectrometry platform (MassArray TM, Sequenom Inc., San Diego, CA, USA) according to a previously described method. 
The χ2 test was used to analyze the Hardy-Weinberg equilibrium. Differences in allele frequencies between controls and cases, odds ratios and 95% confidence intervals were analyzed using the χ2 test or Fisher's exact test. All statistical analyses were performed by SPSS 16.0 software (SPSS Inc.,USA). The criterion for a significant difference was P < 0.05.
| Results|| |
Overall, we excluded 3 NMO patients, 3 MS patients and 8 controls who had a SNP genotyping success rate <90%, remaining a total of 108 NMO patients, 142 MS patients and 292 controls analyzed in this study. Their demographic and clinical characteristics are listed in [Table 2]. Anti-AQP4 antibodies were tested in 68 NMO patients and 35 (51.5%) were positive.
All selected SNPs were in Hardy-Weinberg equilibrium [Table 3]. As showed in [Table 4], there was no significant allele or genotype association for rs2280714, rs3807306, rs4728142 and rs729302 identified in NMO patients compared with controls. Similarly, no statistically significant association was observed for any of the SNPs between MS patients and controls. In further analysis, according to the status of anti-AQP4 antibodies, we found no significance in allele frequencies or genotype distributions among anti-AQP4 antibodies positive NMO patients, MS patients and controls.
|Table 4: Allele and genotype distributions of IRF5 variants among MS, NMO and controls|
Click here to view
| Discussion|| |
Interferon regulatory factor 5 is a common susceptibility gene to different autoimmune disorders. Recent findings have revealed the strongest evidence of associations between variants in the human IRF5 locus and a wide range of autoimmune diseases. In a previous association study on rheumatoid arthritis (RA), 4 SNPs in IRF5 including rs375385, rs2004640, rs752637 and rs3807306 were associated with RA.  At the same time, they also found that IRF5 polymorphisms were associated with inflammatory bowel diseases and systemic lupus erythematosus. , In addition, a GWAS of MS patients showed evidence of association between the rs3807306 of IRF5 and the development of MS in the initial screening phase.  Subsequently, a study by Kristjansdottir et al. reported that the rs4728142 and rs3807306 were associated with MS in three different population cohorts from Sweden, Spain and Finland. 
Here, we constituted a case-control association study in order to investigate the contribution of variants located in IRF5 in NMO and MS susceptibility. To the best of our knowledge, this has been the first effort, in any population, to address the association between NMO and common variants of IRF5. However, no significant difference of genotypes and alleles was detected in NMO patients compared with controls. We also want to determine whether there is an intrinsic association between anti-AQP4 antibodies positive NMO patients and IRF5 variants. So the NMO group was further divided into two disparate disease entities: Anti-AQP4 antibodies positive patients and anti-AQP4 antibodies negative patients. However, we did not see any association of anti-AQP4 antibodies positive NMO patients with IRF5 variants. Therefore, IRF5 variants may not play a major role in genetic predisposition to NMO in the Southeastern Han Chinese population.
In addition, the current study failed to certify a significant association of IRF5 variants with MS. Similarly, these effects were not replicated by Vandenbroeck et al. in North (Bilbao, San Sebastian) Spain.  However, the association of IRF5 variants with MS was observed in the following combined analysis including North, Central and South Spain and Sweden.  Although it is difficult to elucidate the reasons for this discrepancy, several explanations should be considered. First and most importantly, IRF5 polymorphisms are distinct in different ancestral backgrounds. Second, MS is a multifactorial disease caused by the interaction between environmental and inherited factors, different environmental factors such as smoking and lifestyle may affect the results from inherited factors. Third, it could be that the association of these variants has a weak effect size, which this study does not have sufficient power to detect. In addition, there are other SNPs in the same locus associated with MS in the Southeastern Han Chinese population. Hence, further analyses are needed to explore whether other variants associated with MS exist in this locus.
In conclusion, although this is a preliminary study, our results indicate that genetic variants in the IRF5 gene may affect neither NMO nor MS in the Southeastern Han Chinese population. Further studies with a large sample size and diverse ancestry populations are needed to clarify the associations of IRF5 variants with NMO and MS.
| References|| |
Asgari N, Lillevang ST, Skejoe HP, Falah M, Stenager E, Kyvik KO. A population-based study of neuromyelitis optica in Caucasians. Neurology 2011;76:1589-95.
Lennon VA, Wingerchuk DM, Kryzer TJ, Pittock SJ, Lucchinetti CF, Fujihara K, et al.
A serum autoantibody marker of neuromyelitis optica: Distinction from multiple sclerosis. Lancet 2004;364:2106-12.
Yamakawa K, Kuroda H, Fujihara K, Sato S, Nakashima I, Takeda A, et al.
Familial neuromyelitis optica (Devic's syndrome) with late onset in Japan. Neurology 2000;55:318-20.
Matiello M, Kim HJ, Kim W, Brum DG, Barreira AA, Kingsbury DJ, et al.
Familial neuromyelitis optica. Neurology 2010;75:310-5.
International Multiple Sclerosis Genetics Consortium, Hafler DA, Compston A, Sawcer S, Lander ES, Daly MJ, et al.
Risk alleles for multiple sclerosis identified by a genomewide study. N Engl J Med 2007;357:851-62.
Australia and New Zealand Multiple Sclerosis Genetics Consortium (ANZgene). Genome-wide association study identifies new multiple sclerosis susceptibility loci on chromosomes 12 and 20. Nat Genet 2009;41:824-8.
De Jager PL, Jia X, Wang J, de Bakker PI, Ottoboni L, Aggarwal NT, et al.
Meta-analysis of genome scans and replication identify CD6, IRF8 and TNFRSF1A as new multiple sclerosis susceptibility loci. Nat Genet 2009;41:776-82.
Sanna S, Pitzalis M, Zoledziewska M, Zara I, Sidore C, Murru R, et al.
Variants within the immunoregulatory CBLB gene are associated with multiple sclerosis. Nat Genet 2010;42:495-7.
Kim HJ, Park HY, Kim E, Lee KS, Kim KK, Choi BO, et al.
Common CYP7A1 promoter polymorphism associated with risk of neuromyelitis optica. Neurobiol Dis 2010;37:349-55.
Zhao GX, Liu Y, Li ZX, Lv CZ, Traboulsee A, Sadovnick AD, et al.
Variants in the promoter region of CYP7A1 are associated with neuromyelitis optica but not with multiple sclerosis in the Han Chinese population. Neurosci Bull 2013;29:525-30.
Matsushita T, Matsuoka T, Isobe N, Kawano Y, Minohara M, Shi N, et al.
Association of the HLA-DPB1*0501 allele with anti-aquaporin-4 antibody positivity in Japanese patients with idiopathic central nervous system demyelinating disorders. Tissue Antigens 2009;73:171-6.
Wang H, Dai Y, Qiu W, Zhong X, Wu A, Wang Y, et al.
HLA-DPB1 0501 is associated with susceptibility to anti-aquaporin-4 antibodies positive neuromyelitis optica in southern Han Chinese. J Neuroimmunol 2011;233:181-4.
Deschamps R, Paturel L, Jeannin S, Chausson N, Olindo S, Béra O, et al.
Different HLA class II (DRB1 and DQB1) alleles determine either susceptibility or resistance to NMO and multiple sclerosis among the French Afro-Caribbean population. Mult Scler 2011;17:24-31.
Liu QB, Li ZX, Zhao GX, Yu H, Wu ZY. No association between identified multiple sclerosis non-MHC risk loci and neuromyelitis optica. Neurosci Bull 2014;30:1036-44.
Sweeney SE. Targeting interferon regulatory factors to inhibit activation of the type I IFN response: Implications for treatment of autoimmune disorders. Cell Immunol 2011;271:342-9.
Takaoka A, Yanai H, Kondo S, Duncan G, Negishi H, Mizutani T, et al.
Integral role of IRF-5 in the gene induction programme activated by Toll-like receptors. Nature 2005;434:243-9.
Feng D, Sangster-Guity N, Stone R, Korczeniewska J, Mancl ME, Fitzgerald-Bocarsly P, et al.
Differential requirement of histone acetylase and deacetylase activities for IRF5-mediated proinflammatory cytokine expression. J Immunol 2010;185:6003-12.
Fang CM, Roy S, Nielsen E, Paul M, Maul R, Paun A, et al.
Unique contribution of IRF-5-Ikaros axis to the B-cell IgG2a response. Genes Immun 2012;13:421-30.
Polman CH, Reingold SC, Edan G, Filippi M, Hartung HP, Kappos L, et al.
Diagnostic criteria for multiple sclerosis: 2005 revisions to the "McDonald Criteria". Ann Neurol 2005;58:840-6.
Wingerchuk DM, Lennon VA, Pittock SJ, Lucchinetti CF, Weinshenker BG. Revised diagnostic criteria for neuromyelitis optica. Neurology 2006;66:1485-9.
Matsuoka T, Matsushita T, Kawano Y, Osoegawa M, Ochi H, Ishizu T, et al.
Heterogeneity of aquaporin-4 autoimmunity and spinal cord lesions in multiple sclerosis in Japanese. Brain 2007;130:1206-23.
Buetow KH, Edmonson M, MacDonald R, Clifford R, Yip P, Kelley J, et al.
High-throughput development and characterization of a genomewide collection of gene-based single nucleotide polymorphism markers by chip-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Proc Natl Acad Sci U S A 2001;98:581-4.
Sigurdsson S, Padyukov L, Kurreeman FA, Liljedahl U, Wiman AC, Alfredsson L, et al.
Association of a haplotype in the promoter region of the interferon regulatory factor 5 gene with rheumatoid arthritis. Arthritis Rheum 2007;56:2202-10.
Dideberg V, Kristjansdottir G, Milani L, Libioulle C, Sigurdsson S, Louis E, et al.
An insertion-deletion polymorphism in the interferon regulatory Factor 5 (IRF5) gene confers risk of inflammatory bowel diseases. Hum Mol Genet 2007;16:3008-16.
Sigurdsson S, Göring HH, Kristjansdottir G, Milani L, Nordmark G, Sandling JK, et al.
Comprehensive evaluation of the genetic variants of interferon regulatory factor 5 (IRF5) reveals a novel 5 bp length polymorphism as strong risk factor for systemic lupus erythematosus. Hum Mol Genet 2008;17:872-81.
Kristjansdottir G, Sandling JK, Bonetti A, Roos IM, Milani L, Wang C, et al.
Interferon regulatory factor 5 (IRF5) gene variants are associated with multiple sclerosis in three distinct populations. J Med Genet 2008;45:362-9.
Vandenbroeck K, Alloza I, Swaminathan B, Antigüedad A, Otaegui D, Olascoaga J, et al
. Validation of IRF5 as multiple sclerosis risk gene: Putative role in interferon beta therapy and human herpes virus-6 infection. Genes Immun 2011;12:40-5.
[Table 1], [Table 2], [Table 3], [Table 4]