Interleukin-1-related genes polymorphisms in Turkish patients with Behçet disease: a meta-analysis

Immunopathogenesis of Behçet's disease and treatment modalities

INTRODUCTION

Behçet's disease (BD) is an auto-inflammatory disease, primarily characterized by recurrent painful mucocutaneous ulcerations.

METHODS

A literature search was performed to write a narrative review into the pathogenesis and current treatment options of BD.

RESULTS

The pathogenesis of BD remains to be elucidated, but is considered a genetically primed disease in which an external trigger causes immune activation resulting in inflammatory symptoms. GWAS data show an association between multiple genetic polymorphisms (HLA-B51, ERAP1, IL10 and IL23R-IL12RB2) and increased susceptibility to BD. Bacteria as streptococci, an unbalanced microbiome or molecular mimicry trigger the inflammation in BD. Increased production or responsiveness of pro-inflammatory components of the innate immune response (TLR, neutrophils, NK-cells or γδ T-cells) to these triggers may be a crucial step in the pathogenesis of BD. Additionally to an increased autoinflammatory response there is evidence of a dysregulated adaptive immune system, with a disturbed Th1/Th2 balance, expansion of Th17 cells and possibly a decrease in regulatory T cells, resulting in a surplus in pro-inflammatory cytokines. The inflammation causes a typical clinical phenotype including orogenital ulcerations, uveitis and skin lesions. Treatment is aimed at the aberrations found in the innate (neutrophils and γδ-T cells) and adaptive immune system (TNF-α, INF-γ, IL-1), directed at organ involvement and individualized based on patient characteristics.

CONCLUSION

We presented an extensive review into the pathogenesis and treatment options of BD.

Global Meta-Analysis on the Association between Behcet Syndrome and Polymorphisms from the HLA Class I (A, B, and C) and Class II (DRB1, DQB1, and DPB1) Genes

Behcet syndrome (BS) is a multisystemic perivasculitis whose genetic susceptibility is linked to HLA region. We first meta-analysed all HLA class I and II genes involved in BS susceptibility in all ethnic groups worldwide. We identified 1141 articles and finally included 31 case-control studies after multiple rounds of selection. We analysed frequencies for 24 HLA-A alleles (3 alleles for HLA-A∗26 at four digits), 50 HLA-B alleles (11 alleles for HLA-B∗51 at four digits), 15 HLA-C alleles, 16 HLA-DRB1 alleles, 6 HLA-DQB1 alleles, and 15 HLA-DPB1 alleles. We meta-analysed only HLA allelic frequencies from at least three studies; therefore, we investigated 21 alleles out of 140. Going from 7.00 to 1.6 OR, we found 11 class I alleles conferring risk for BS: B∗51 : 08, B∗51, B∗51 : 01, B∗51 : 02, DQB1∗03, A∗26 : 01, Cw∗14, Cw∗15, Cw∗16, B∗15, and A∗26. Overall, the studies included populations from Europe (Greece, Spain, Italy, Germany, and Ireland), Asia (Korea, China, China Han, and Thailand), Middle East (Israel, Saudi Arabia, and Iran), and Morocco (as no other North-African population was included). We collected a number of ethnical groups sufficient to conduct an ethnic-specific meta-analysis where Europeans showed 11.25 OR for B∗51:08 and Japan 3.50 OR for A∗26 : 01. A remarkable result was that the most frequent HLA − B∗51 two-digit alleles associated with BS were different among populations: HLA − B∗51 : 08 in Europe, HLA − B∗51 : 01 in Turkey, and HLA − B∗51 : 02 in Japan. Overall, we discussed our real-world results with other imputation studies.

The role of the inflammasomes in the pathogenesis of uveitis

Uveitis is a diverse group of sight-threatening intraocular inflammatory diseases usually causing eye redness, pain, blurred vision, and sometimes blindness. Although the exact pathogenesis of uveitis is not yet clear, accumulating evidences have shown that an imbalanced regulation of immune responses caused by a combination of genetic and environmental factors are implicated in the pathogenesis of this disease. As critical regulators of inflammation, inflammasomes have been assumed to play a role in the pathogenesis of uveitis. Recent studies have reported the association between a number of genetic variants in inflammasome related genes (such as NLRP3, NLRP1, NLRC4 and AIM2) with increased risk to uveitis. Mounting evidence have shown an aberrant activation of the NLRP3 inflammasome in both uveitis patients and murine models of uveitis. Some studies explored the intervention of uveitis via modulating inflammasome activity in the eye. This review aims at summarizing the main findings of these studies, proposing the possible mechanism whereby inflammasomes affect the susceptibility to develop uveitis, and giving a perspective for future studies, which may further improve our understanding about the role of inflammasomes and related cytokines in the pathogenesis of uveitis, and may hopefully lead to new therapeutics by targeting inflammasomes.

Updated treatment strategies for intestinal Behçet's disease

Behçet's disease (BD) is a chronic, idiopathic, relapsing immune-mediated disease involving multiple organs, and is characterized by recurrent oral and genital ulcers, ocular disease, gastrointestinal ulcers, vascular diseases, and skin lesions. In particular, gastrointestinal involvement in BD is followed by severe complications, including massive bleeding, bowel perforation, and fistula, which can lead to significant morbidity and mortality. However, the management of intestinal BD has not yet been properly established. Intestinal BD patients with a severe clinical course experience frequent disease aggravations and often require recurrent corticosteroid and/or immunomodulatory therapies, or even surgery. However, a considerable number of patients with intestinal BD are often refractory to conventional therapies such as corticosteroids and immunomodulators. Recently, there has been a line of evidence suggesting that biologics such as infliximab and adalimumab are effective in treating intestinal BD. Moreover, new biologics targeting proteins other than tumor necrosis factor α are emerging and are under active investigation. Therefore, in this paper, we review the current therapeutic strategies and new clinical data for the treatment of intestinal BD.

Investigating the role of IL-33 in the pathogenesis of Behçet's Disease

OBJECTIVES

Behçet's disease (BD) is an inflammatory disease, characterized by oral aphthous lesions, recurrent uveitis, skin lesions, and genital ulcerations. Increased release of several cytokines may play a role in the inflammatory stages of BD. IL-33, a member of the IL-1 cytokine superfamily, plays an important role in inflammation. We analyzed serum IL-33 concentration in BD patients to assess its possible role in the pathophysiology of this disease.

METHODS

The study included 54 BD patients, 31 with active BD and 23 with inactive BD as well as 18 matched healthy controls. Serum IL-33 levels were measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

The mean serum IL-33 levels were 4.84 ± 2.81 pg/ml in the BD patients (6.16 ± 2.94 pg/ml in the active stage and 2.86 ± 0.54 pg/ml in the inactive stage) and 2.88 ± 0.42 pg/ml in the healthy controls. Serum IL-33 levels were significantly higher in patients with BD compared with the healthy controls (p < 0.01). In active Behçet patients with arthritis the mean serum IL-33 level was higher but this finding was not statistically significant (p = 0.122).

CONCLUSION

IL-33 may play a significant role of in the pathogenesis of BD.

Investigational drugs in systemic vasculitis

INTRODUCTION

Treatment of systemic vasculitis is based on glucocorticoids (GC) in association with immunosuppressive therapy. There are still unmet needs, including earlier onset of response, more targeted therapies, reduction of relapse-risk and decrease of long-term GC and classic immunosuppressants toxicities. Areas covered: In this review, we discuss investigational drugs in early phase clinical trials for induction of remission in vasculitis. We focus on ANCA-associated vasculitis, Behçet's disease, giant cell arteritis, Takayasu arteritis, and cryoglobulinemic vasculitis. We performed a comprehensive review of articles published on pubmed and a review of clinical trials registered online ( https://clinicaltrials.gov ) for each vasculitis. Expert opinion: Recent progress in the pathogenesis identifies new therapeutic targets. Some of these therapies are promising in GC sparing effects, in reducing relapse rate, and for their safety profile. These results need to be confirmed in large-scale phase III studies.

An elevated pro-inflammatory cytokines profile in Behcet's disease: A multiplex analysis

The serum levels of sixteen cytokines related to innate immunity, Th1, Th2 and Th17 cells in the sera of 44 patients with Behcet's Disease (BD) and 44 healthy controls have been investigated using the cytokine array technique. Among the cytokines related to innate immunity, the levels of IL-1α, IL-1 β, IL-6, IL-12, IL-15 and TNF-α were statistically higher in BD patients than healthy controls. In the case of Th1- and Th17-related cytokines, IL-2, IFN-γ, IL-17 and IL-23 were significantly higher in patients. From Th2-related cytokines, only IL-13 showed statistically higher levels in patients than controls. Among different evaluated cytokines, the differences in IL-1 α, IL-1 β, IL-6 and Ʃinnate-related cytokines were more prominent between cases and controls. In addition, the results showed that Ʃinnate- and ƩTh17-related cytokines are better indicators of cytokines imbalances in BD than each one of the innate- and Th17-related cytokines. Moreover, disease activity score and clinical activity index can also be affected by the levels of pro-inflammatory (IL-6) and anti-inflammatory (IL-4) cytokines. In conclusion, the results revealed that imbalances in the expression of innate immunity- as well as Th1- and Th17-related cytokines may play not only a pivotal role in BD pathogenesis but also can be important in disease severity.

Pro-inflammatory cytokine single nucleotide polymorphisms in Kawasaki disease

AIM

Kawasaki disease (KD) is a systemic vasculitis of children associated with cardiovascular sequelae. Proinflammatory cytokines play a major role in KD pathogenesis. However, their role is both influenced and modified by regulatory T-cells. IL-1 gene cluster, IL-6 and TNF-α polymorphisms have shown significant associations with some vasculitides. Herein we investigated their role in KD.

METHODS

Fifty-five patients with KD who were randomly selected from referrals to the main pediatric hospital were enrolled in this case-control study. Single nucleotide polymorphisms (SNPs) of the following genes were assessed in patients and 140 healthy subjects as control group: IL-1α at -889 (rs1800587), IL-1β at -511 (rs16944), IL-1β at +3962 (rs1143634), IL-1R at Pst-I 1970 (rs2234650), IL-1RN/A at Mspa-I 11100 (rs315952), TNF-α at -308 (rs1800629), TNF-α at -238, IL-6 at -174 (rs1800795) and IL-6 at +565.

RESULTS

Twenty-one percent of the control group had A allele at TNF-α -238 while only 8% of KD patients had A allele at this position (P = 0.003, OR [95%CI] = 0.32 [0.14-0.71]). Consistently, TNF-α genotype GG at -238 had significant association with KD (OR [95% CI] = 4.31 [1.79-10.73]). Most controls carried the CG genotype at IL-6 -174 (n = 93 [66.9%]) while GG genotype was the most common genotype (n = 27 [49%]) among patients. Carriers of the GG haplotype at TNF-α (-308, -238) were significantly more prevalent among the KD group. No association was found between IL-1 gene cluster, allelic or haplotypic variants and KD.

CONCLUSION

TNF-α GG genotype at -238 and GG haplotype at positions -308 and -238 were associated with KD in an Iranian population.

Basic Characteristics of Adults with Periodic Fever, Aphthous Stomatitis, Pharyngitis, and Adenopathy Syndrome in Comparison with the Typical Pediatric Expression of Disease

Autoinflammatory diseases are caused by inflammasome dysregulation leading to overproduction of proinflammatory cytokines and a pathological delay in the inflammation switching off. The progress of cellular biology has partially clarified pathogenic mechanisms behind monogenic autoinflammatory diseases, whereas little is known about the polygenic ones. Although the genetic susceptibility of periodic fever, aphthous stomatitis, pharyngitis, and adenopathy (PFAPA) syndrome is still obscure, the presence of overlapping symptoms with monogenic periodic fevers, the recurrence in family members, the important role played by dysregulated interleukin- (IL-) 1β secretion during flares, the overexpression of inflammasome-associated genes during attacks, and, last but not least, the therapeutic efficacy of IL-1β blockade strongly indicate a potential genetic involvement in its pathogenesis, probably linked with environmental factors. PFAPA syndrome has a typical inception in the pediatric age, but a delayed onset during adulthood has been described as well. Treatments required as well as effectiveness of tonsillectomy remain controversial, even if the disease seems to have a self-limited course mostly in children. The purpose of this review is to provide an overview of this complex polygenic/multifactorial autoinflammatory disorder in which the innate immune system undoubtedly plays a basic role.

Efficacy and safety profile of anti-interleukin-1 treatment in Behçet's disease: a multicenter retrospective study

Growing data have provided encouraging results on the use of interleukin (IL)-1 inhibitors in Behçet's disease (BD). This study was aimed at reporting the largest experience with anti-IL-1 agents in BD patients. We evaluated 30 BD patients receiving treatment with anti-IL-1 agents. The primary aims of the study were to evaluate the efficacy of anakinra (ANA) and canakinumab (CAN) in a cohort of BD. The secondary aims were to evaluate the overall safety profile of the treatments, explore the timing of response to therapy and any adjustment of dosage and frequency of drugs studied, and investigate predictive factors of response to therapy. The frequency of first line therapy was 90 % with ANA and 10 % with CAN. The overall number of subjects in complete remission after 12 months of therapy with anti-IL-1 drugs was 13: 6 maintained the initial therapy regimen, 1 maintained the same initial anti-IL-1 drug with further therapeutic adjustments, and the remaining 6 shifted from ANA to CAN. Among them, 3 used CAN for at least 12 months without therapeutic adjustments, 1 had therapeutic adjustments, and 3 had an overall history of a 12-month complete remission. Adverse events (AEs) were reported in 15 % patients who received ANA, represented in all cases by local cutaneous reactions, while no AE were observed in patients who received CAN; we did not observe any serious AEs (SAEs) during the follow-up period. Our data have confirmed that the use of anti-IL-1β drugs is efficacious and safe with an overall acceptable retention on treatment.

Expression profile of IL-1 family cytokines in aqueous humor and sera of patients with HLA-B27 associated anterior uveitis and idiopathic anterior uveitis

The purpose of this study was to evaluate the cytokine expression profile of specific IL-1 family members in the aqueous humor and sera of patients with HLA-B27 associated acute anterior uveitis (AAU) and idiopathic AAU. Following informed consent, a total of 13 patients with HLA-B27 associated AAU, 12 patients with idiopathic AAU and 9 controls were recruited to this study from May 2013 to July 2014. Each individual received a complete ophthalmologic examination. Aqueous humor and sera samples were collected and 11 inflammation-related cytokines of the IL-1 family (IL-1α, IL-1β, IL-1 receptor antagonist [IL-1Ra], IL-18, IL-36 receptor antagonist [IL-36Ra], IL-33, IL-36α, IL-36β, IL-36γ, IL-37, IL-38) were quantitatively measured and analyzed for statistical significance between groups. The degree of inflammation, anterior chamber cell or flare, correlated with expression of IL-1β, IL-1Ra, and IL-18. The highest levels of IL-1β, IL-1Ra, IL-18, and IL-36Ra were seen in the aqueous of patients with HLA-B27 associated AAU and this was statically significant when compared to the controls, but not to idiopathic AAU. Expression of IL-18 was statistically higher in the aqueous of patients with HLA-B27 associated AAU in comparison to either idiopathic AAU or controls, but this may reflect greater inflammation in this patient group. In the sera only IL-1α was statistically higher in the HLA-B27 associated AAU in comparison to the control. Cytokine analysis reveals elevation of multiple IL-1 family members in the aqueous humor of patients with AAU as compared to controls. The specific signature of inflammation may potentially be useful in developing new future therapies for AAU.

PFAPA syndrome and Behçet's disease: a comparison of two medical entities based on the clinical interviews performed by three different specialists

The pediatric syndrome characterized by periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis (PFAPA) and adult Behçet's disease share some clinical manifestations and are both polygenic autoinflammatory disorders with interleukin-1β showing to play a pivotal role. However, the diagnosis is mostly clinical and we hypothesize that specific criteria may be addressed differently by different physicians. To determine the diagnostic variability, we compared the answers of 80 patients with a definite diagnosis of Behçet's disease (age 42.1 ± 13.7 years) obtained by separate telephone interviews conducted by a rheumatologist, a pediatrician, and an internist working largely in the field of autoinflammatory disorders. Questions were related to the age of symptom onset, the occurrence of recurrent fevers during childhood, and the association with oral aphthosis, cervical adenitis and/or pharyngitis, previous treatments, possible growth impairment, the time lapse between PFAPA-like symptoms and the onset of Behçet's disease, and the occurrence of Behçet-related manifestation during childhood. The rheumatologist identified 30 % of patients with Behçet's disease fulfilling PFAPA syndrome diagnostic criteria, compared to the pediatrician and the internist identifying 10 and 7.5 %, respectively. Most of the patients suffered from recurrent oral aphthosis in childhood also without fever (50, 39, and 48 % with each interviewer), yet no patient fulfilled the Behçet's disease diagnostic criteria. Our data suggest that physician awareness and expertise are central to the diagnosis of autoinflammatory disorders through an accurate collection of the medical history.