Distribution of rs17482078 and rs27044 ERAP1 polymorphisms in a group of Italian Behçet's syndrome patients: a preliminary case-control study

TNFα rs1800629 Polymorphism and Response to Anti-TNFα Treatment in Behçet Syndrome: Data from an Italian Cohort Study

Tumor Necrosis Factor-alpha (TNFα) rs1800629 (-308G>A) is a single nucleotide polymorphism (SNP) related to variable responses to anti-TNFα therapy. This therapy is efficient in severe and refractory manifestation of Behçet syndrome (BS), an auto-inflammatory systemic vasculitis. We investigated (1) the association between rs1800629 genotypes and responses to therapy and (2) the correlation between SNP and clinical patterns in a cohort of 74 BS Italian patients receiving anti-TNFα therapy with a follow-up of at least 12 months. The rs1800629 was genotyped through amplification, direct sequencing and bioinformatics analyses. The rs1800629 GG and GA genotypes were assessed as predictors of outcomes dividing the patients between therapy responders and non-responders. The rs1800629 GG and GA genotypes were found, respectively, in 59/74 (79.7%) and 15/74 BS patients (21.3%) (p < 0.05). We identified 16/74 (21.9%) non-responder patients, of which 9/16 (56.3%) showed the GG genotype and 7/16 (43.7%) the GA genotype. A total of 50/58 (86.2%) responder patients showed the GG genotype, and 8/58 (13.8%) the GA genotype (p < 0.05). The percentage of non-responder females (68.8%) was significantly higher than non-responder males (31.2%) (p < 0.05). No correlation between SNP and clinical patterns was observed. To successfully include rs1800629 as a predictive biomarker of TNFα inhibitor response, genome-wide association studies in larger, well-characterised cohorts are required.

A Darwinian View of Behçet's Disease

Behçet's disease (BD) is a multisystem inflammatory disorder of unknown etiology, characterized by oral and genital ulceration, with other complications including eye, skin, joint, and central nervous system (CNS) lesions. Diagnosis is based on clinical findings, which may differ between patients. There is a strong genetic basis for BD; however, only a few genes have been associated with the disease across the geographical spread of BD. In this article, we discuss the history and combination of genes involved in this complex disease in relation to the geographical range and present our view that the disease has developed from a Darwinian perspective, with different gene polymorphisms that affect the same biological pathway. Moreover, these mutations individually are protective mechanisms against the disease relevant to each region, which affected both archaic and modern humans.

Clinical phenotypes of Behçet's syndrome in a large cohort of Italian patients: focus on gender differences

Objective: The aim of this study was to investigate the clinical phenotypes of Italian patients with Behçet's syndrome (BS) according to gender. BS is a rare chronic multisystemic disorder with a wide spectrum of clinical manifestations. Human leucocyte antigen (HLA)-B51, gender, and ethnicity have been suggested as factors that could influence the clinical manifestations in BS patients. To date, few data assessing gender differences in Italian BS patients are available in the literature.Method: We retrospectively evaluated a group of Italian patients seen consecutively at our dedicated tertiary centre from 1 January 2000 to 31 May 2018. Demographics, clinical features during follow-up, and HLA status were obtained from a review of medical records and analysed in male and female groups.Results: In total, 285 [168 male (M) and 117 female (F)] patients were eligible for the study. Males had papulopustolar lesions, posterior uveitis, and deep venous thrombosis more often than females (83.3% M vs 46.2% F, 36.9% M vs 18.8% F, and 8.3% M vs 0.9% F, respectively; p < 0.01). Erythema nodosum (59.0% F vs 41.1% M; p < 0.01) and arthralgia (52.1% F vs 31.6% M; p < 0.01) were more frequent in females. No differences were found in HLA-B51 status (59.2% M vs 59.0% F).Conclusion: In our Italian cohort, BS was slightly more prevalent in males. Some gender-related differences were observed when comparing male and female cohorts. The data also confirmed that BS tends to be less aggressive in Italian female patients.

Experimental Therapeutic Solutions for Behcet's Disease

Behcet’s disease (BD) is a chronic systemic vasculitis with inflammation attacks that involve multiple organs. In addition to numerous mucocutaneous symptoms, notably recurrent oral and genital ulcers, ocular, articular, vascular, gastrointestinal, cardiac, and neurological system involvement can be observed. Mucocutaneous lesions are the primary symptom of the disease in most patients, and they usually occur before major organ involvement and other symptoms of the disease. Recognizing the disease’s mucocutaneous lesions is very important to diagnose at an early stage, control with appropriate treatment and close follow-up, and prevent major organ involvement. Genome-wide association studies (GWAS) in recent years have confirmed that HLA-B*51 is the most significant genetic predisposing factor. The majority of gene polymorphisms have been detected in molecules that respond to microorganisms and genes encoding cytokines and adhesion molecules. The infectious agent S. sanguinis -commonly found in the oral mucosa of patients with BD- or the differences in the salivary or intestinal microbiome composition can trigger innate immune-mediated inflammation sustained by acquired or adaptive immune responses. In antigen-presenting cells (APCs), epistatic interactions between HLA-B*51 and endoplasmic reticulum aminopeptidase 1 (ERAP1) variants lead to the disruption of T-cell homeostasis, especially the activation of Type1 T-helper and Th17 pathway and suppression of regulatory T-cells. Recent developments to clarify the disease’s etiopathogenesis provided us with a better understanding of the mechanism of action of the relatively old drugs while opening a way for many new treatment methods. Apremilast has become an important option in the treatment of mucocutaneous symptoms with its high efficacy and safety. The disease increases the mortality rate, especially in young male patients. New treatments, especially anti-TNF-α agents, have provided significant progress and decreased the mortality rates with their rapid effect and high efficacy in patients with severe organ involvement and resistance to traditional immunosuppressive and immunomodulatory therapies. The use of IL-1, IL-6, IL-17, IL-12/IL-23 antagonists in different organ involvement has gradually increased, and the quality of life has significantly improved in many patients.

A First Step for the Molecular Characterization of Neurological Involvement of Behçet Syndrome: an Italian Pivotal Study

Behçet syndrome (BS) is a vasculitis characterized by several clinical manifestations including the rare neurological involvement (neuro-BS, NBS). The aim of our pivotal study was to investigate the mutational status of several inflammation-related genes in a cohort of Italian patients with and without the neurological involvement (20 NBS vs 40 no-NBS patients). The preliminary in silico single nucleotide polymorphism (SNP) selection and primer design were performed by NCBI Primer-Blast tool. Genomic DNA was isolated and amplified using PCR. PCR amplicons were sequenced and bioinformatically analysed. Twelve tagSNPs were selected and genotyped: ERAP1 rs30187, rs17482078, and rs27044; IL10 rs1800872 and rs1518111, IL12A rs17810546, IL23R rs17375018, IL23R-IL12RB2 rs924080, STAT4 rs7572482, CCR1 rs7616215, KLRC4 rs2617170, and UBAC2 rs3825427. ERAP1 and IL23R SNPs showed statistically significant higher frequencies in NBS group than no-NBS. ERAP1 rs30187 AA was more common in no-NBS patients (20.0% NBS vs 47.5% no-NBS; p < 0.05), while rs17482078 GA frequency was higher in NBS patients (55.0% NBS vs 22.5% no-NBS; p < 0.05, OR: 4.21). IL23R rs17375018 GG was more frequent in NBS group (65.0% NBS vs 40.0% no-NBS; p < 0.05), according to a previous finding. No other statistically significant differences were found. In conclusion, ERAP1 and IL23R SNPs were found associated with neurological involvement of BS. Additional and larger analyses were required to verify our preliminary findings.

From structure to function for the characterization of ERAP1 active site in Behçet syndrome. A novel polymorphism associated with known gene variations

INTRODUCTION

ERAP1 has been recently proposed as risk marker of Behçet syndrome (BS). Gene single nucleotide polymorphisms (SNPs) could affect the enzymatic activity and the conserved active site is pivotal for the aminopeptidase function. This study aims to characterize the ERAP1 active site in a cohort of BS patients vs healthy controls (HC) integrating genomics, transcriptomics and bioinformatics approach.

MATERIALS AND METHODS

We recruited 109 consecutive Italian BS patients (63M:46 F; mean age: 45.07 ± 12.28 years) and 106 matched HC (55M:51 F; mean age: 42.57 ± 12.29 years). DNA was isolated and amplified using PCR with home made-primer pairs. PCR products were directly sequenced and computational analyses were performed to search active site SNPs (NCBI-BlastN tool), to predict SNPs functional effect (PolyPhen-2 software) and to obtain protein 3D modelling (Protean3D software). In a second phase of analysis, RNA was extracted and reverse transcribed. Quantitative Real-Time PCR (qPCR) was performed to assess ERAP1 mRNA level in presence (target) and in absence (control) of gene polymorphisms. The Fold change was calculated for the relative quantification of gene expression.

RESULTS

A novel coding variation (NG_027839.1:g.25637 T > G; NP_057526.3:p.Phe360Cys, HGSV nomenclature) was found in heterozygosity state in 5/109 BS patients (4.59 % of cases) and none of HC. It was recognized in association with rs2287987, rs30187, rs17482078, and rs27044 BS-related polymorphisms for 4 out of 5 patients. All patients carrying the novel SNP were HLA-B*51-positive. The novel SNP was released in GenBank database with MK140632.1 ID. The SNP was predicted to be damaging and resides within the Zn-binding HEXXH(X)₁₈E region of the active site, changing the structurally conserved region for the amminopeptidase function. In fact, the change in energy (ΔE) score between wild-type and SNP-containing protein showed a less stable protein in presence of p.Cys360 (ΔE:3.584) (Protean3D prediction). Preliminary qPCR results underlined a significant difference in fold change value when target and control values were compared (p < 0.05), suggesting a reduced expression of ERAP1 mRNA in presence of the novel SNP.

CONCLUSIONS

Our study strengthens the association between ERAP1 and BS. The most significant point was the localization of the novel p.Phe360Cys SNP within the Zn-binding region of protein active site that was predicted to affect its function, causing protein destabilization. Our findings need to be tested in larger genetic studies.