Association of Endoplasmic Reticulum Aminopeptidase 1 Gene Polymorphism with Susceptibility and Severity of Axial Spondyloarthritis in Egyptian Population: A Single-center Case-Control Study.

BACKGROUND: Axial spondyloarthritis (axSpA) is a systemic, progressive, autoimmune disease. Complex interactions between environmental factors and host immune responses are the origin of axSpA. Together with human leukocyte antigen (HLA-B27), endoplasmic reticulum aminopeptidase 1 (ERAP1) gene is a potential non-HLA contributor to axSpA susceptibility. AIM: This study aimed to identify the role of ERAP1 single-nucleotide polymorphisms (SNPs) (rs30187, rs27044, and rs27037) in susceptibility to and severity of axSpA in Egyptian patients. METHODS: In this case-control study, we enrolled 120 patients with axSpA and 120 healthy individuals as controls. Real-time polymerase chain reaction was used to identify ERAP1 polymorphisms. RESULTS: The present study revealed no significant association between ERAP1 SNPs (rs30187, rs27044, and rs27037) and axSpA susceptibility in Egyptian patients. A significant relationship was found only between the ERAP1 SNP rs27037 "GT" genotype and axSpA HLA-B27-positive cases, demonstrating a functional interaction between ERAP1 and HLA-B27-positive cases. Our analysis revealed a significant association between the ERAP1 SNP rs27037 "GT and TT" genotypes and Bath Ankylosing Spondylitis Disease Activity Index, in addition to an association between the ERAP1 SNP rs27037 "TT" genotype and active enthesitis. The ERAP1 SNP rs27044 "GG" genotype was significantly associated with active enthesitis, but not with clinical axial involvement. Finally, we did not observe a significant relationship between HLA-B27 positivity and disease severity in the studied cases. CONCLUSION: Three SNPs (rs30187, rs27044, and rs27037) in ERAP1 do not confer susceptibility to axSpA in Egyptian patients. This association existed exclusively between the ERAP1 SNP (rs27037) "GT" genotype and axSpA HLA-B27-positive cases.

Résumé Contexte:la spondyloarthrite axiale (SpAx) est une maladie auto-immune systémique et progressive. Les interactions complexes entre les facteurs environnementaux et les réponses immunitaires de l'hôte sont à l'origine de la SpAx. En plus de l'antigène leucocytaire humain (HLAB27), le gène de l'aminopeptidase du réticulum endoplasmique 1 (ERAP1) est un contributeur potentiel non-HLA à la susceptibilité à la SpAx.Objectif:cette étude visait à identifier le rôle des polymorphismes mononucléotidiques (SNP) de l'ERAP1 (rs30187, rs27044 et rs27037) dans la susceptibilité et la gravité de la SpAx chez les patients égyptiens.Méthodes:dans cette étude cas-témoins, nous avons inclus 120 patients atteints de SpAx et 120 individus en bonne santé comme témoins. La réaction en chaîne de la polymérase en temps réel a été utilisée pour identifier les polymorphismes de l'ERAP1.Résultats:cette étude a révélé qu'il n'y avait pas d'association significative entre les SNP de l'ERAP1 (rs30187, rs27044 et rs27037) et la susceptibilité à la SpAx chez les patients égyptiens. Une relation significative a été trouvée uniquement entre le génotype "GT" du SNP rs27037 de l'ERAP1 et les cas de SpAx positifs pour le HLA-B27, démontrant une interaction fonctionnelle entre l'ERAP1 et les cas positifs pour le HLA-B27. Notre analyse a révélé une association significative entre les génotypes "GT et TT" du SNP rs27037 de l'ERAP1 et l'indice d'activité de la maladie de spondylarthrite ankylosante de Bath, ainsi qu'une association entre le génotype "TT" du SNP rs27037 de l'ERAP1 et l'enthésite active. Le génotype "GG" du SNP rs27044 de l'ERAP1 était significativement associé à l'enthésite active, mais non à l'atteinte axiale clinique. Enfin, nous n'avons pas observé de relation significative entre la positivité du HLA-B27 et la gravité de la maladie dans les cas étudiés.Conclusion:trois SNP (rs30187, rs27044 et rs27037) dans l'ERAP1 ne confèrent pas de susceptibilité à la SpAx chez les patients égyptiens. Cette association existait exclusivement entre le génotype "GT" du SNP rs27037 de l'ERAP1 et les cas de SpAx positifs pour le HLA-B27.

Identification of the novel HLA-B*27:276 allele by next-generation sequencing.

The novel HLA-B*27:276 allele differs from HLA-B*27:05:02:05 by one nucleotide substitution in exon 1.

Diagnosis challenges in inception cohorts in axial spondyloarthritis: the case of the French national DESIR cohort.

BACKGROUND: Inception cohorts aim to describe chronic diseases from diagnosis and over years of follow-up. Axial spondyloarthritis (axSpA) diagnosis might be challenging during the first years of the disease. Thus, identifying the features that will be associated with a confirmed diagnosis over time is key. OBJECTIVES: To assess the frequency and the predisposing factors for a change of an initial diagnosis in an inception axSpA cohort. METHODS: DESIR is an ongoing national multicentre inception axSpA cohort with currently 12.5 years of follow-up. At the entry visit and confirmed at each visit, the diagnosis of axSpA was based on the opinion of the treating rheumatologist. Follow-up was interrupted in case of a change in this initial diagnosis. Multiple imputation was used to estimate the probability of a change in the initial diagnosis of axSpA for each patient lost to follow-up. Factors predisposing to an unchanged diagnosis of axSpA were then assessed using a multivariate logistic regression model on the imputed data sets. RESULTS: Of the 708 patients included, over 10 years of follow-up, 45 (6.4%) were excluded due to a diagnosis change and 300 (42.4%) patients were lost to follow-up. Based on the imputation of these 300 patients, a change in their initial axSpA diagnosis was estimated in 42 (14.0%). Factors predisposing to an unchanged initial axSpA diagnosis during follow-up were (ORs (95% CIs)): radiographic sacroiliitis: 17.0 (4.1 to 71.0); psoriasis: 5.3 (2.0 to 14.3); CRP≥6 mg/L: 2.7 (1.3 to 5.3); good NSAID response: 2.5 (1.5 to 4.2); HLA B27+: 2.0 (1.3 to 3.3); anterior chest wall pain: 2.0 (1.2 to 3.3) and female sex: 1.9 (1.2 to 3.0). CONCLUSION: These data suggest that a change in diagnosis in recent onset axSpA exists, but is not frequent, and is less likely to occur in the presence of objective features at baseline.

TGFß signaling pathway is altered by HLA-B27 expression, resulting in pathogenic consequences relevant for spondyloarthritis.

BACKGROUND: Association of HLA-B27 with spondyloarthritis (SpA) has been known for 50 years, but still remains unexplained. We recently showed that HLA-B27 expressed in wing imaginal disc from HLA-B27/human-ß2 microglobulin (hß2m) transgenic Drosophila deregulated bone morphogenetic protein (BMP) pathway by interacting physically with type I BMP receptor (BMPR1) Saxophone (Sax), leading to crossveinless phenotype. METHODS: Genetic interaction was studied between activin/transforming growth factor ß (TGFß) pathway and HLA-B27/hß2m in transgenic Drosophila wings. The HLA-B27-bound peptidome was characterized in wing imaginal discs. In mesenteric lymph node (mLN) T cells from HLA-B27/hß2m rat (B27 rat), physical interaction between HLA-B27 and activin receptor-like kinase-2 (ALK2), ALK3 and ALK5 BMPR1s, phosphorylation of small mothers against decapentaplegic (SMADs) and proteins of the non-canonical BMP/TGFß pathways induced by its ligands, and the transcript level of target genes of the TGFß pathway, were evaluated. RESULTS: In HLA-B27/hß2m transgenic Drosophila, inappropriate signalling through the activin/TGFß pathway, involving Baboon (Babo), the type I activin/TGFß receptor, contributed to the crossveinless phenotype, in addition to deregulated BMP pathway. We identified peptides bound to HLA-B27 with the canonical binding motif in HLA-B27/hß2m transgenic Drosophila wing imaginal disc. We demonstrated specific physical interaction, between HLA-B27/hß2m and mammalian orthologs of Sax and Babo, i.e. ALK2 and ALK5 (i.e. TGFß receptor I), in the mLN cells from B27 rat. The magnitude of phosphorylation of SMAD2/3 in response to TGFß1 was increased in T cells from B27 rats, showing evidence for deregulated TGFß pathway. Accordingly, expression of several target genes of the pathway was increased in T cells from B27 rats, in basal conditions and/or after TGFß exposure, including Foxp3, Rorc, Runx1 and Maf. Interestingly, Tgfb1 expression was reduced in naive T cells from B27 rats, even premorbid, an observation consistent with a pro-inflammatory pattern. CONCLUSIONS: This study shows that HLA-B27 alters the TGFß pathways in Drosophila and B27 rat. Given the importance of this pathway in CD4 + T cells differentiation and regulation, its disturbance could contribute to the abnormal expansion of pro-inflammatory T helper 17 cells and altered regulatory T cell phenotype observed in B27 rats.

Exploring the Pathogenesis of Spondylarthritis beyond HLA-B27: A Descriptive Review.

Spondylarthritis (SpA) is a chronic inflammatory condition that encompasses damage to the axial or peripheral skeleton, accompanied by specific extra-articular symptoms. Within this group, Ankylosing Spondylitis stands out as the hallmark member. Although the heritability of Ankylosing Spondylitis is estimated to be over 95%, only a portion of the heritability has been explained, with HLA-B27 accounting for 20.1% of it; therefore, ongoing research endeavors are currently concentrated on investigating the potential participation of different entities in the development of the disease. Genome-wide association studies have led to significant advances in our understanding of the genetics of SpA. In this descriptive review, we delve into the pathogenesis of Spondylarthritis beyond HLA-B27. We summarize the latest research on the potential participation of various entities in the development of the disease, including other genetic loci, immune dysregulation, microbiota, and environmental factors. The multifactorial nature of SpA and the complex interplay of genetic, immunological, and environmental factors are being increasingly recognized; therefore, it is of paramount importance to consider a holistic approach to comprehend the pathogenesis of SpA in order to identify novel therapeutic targets.

Differences between radiographic and non-radiographic axial spondyloarthritis patients in a Mexican cohort.

To compare the demographic, clinical, and laboratory characteristics, disease onset, and clinical features of radiographic axial Spondyloarthritis (r-axSpA) and non-radiographic axial Spondyloarthritis (nr-axSpA) patients. All patients who attended outpatient spondylarthritis (SpA) clinics at Hospital General de Mexico and the Instituto Nacional de la Nutrición from 1998 to 2005 and met the rheumatologist diagnostic criteria for SpA were selected. Then the SpA patients were classified by European Spondyloarthropathy Study Group criteria (ESSG). We selected SpA patients with axial presentation as axial SpA (axSpA), and they were classified as r-axSpA if they met modified New York (mNY) criteria for sacroiliitis and as nr-axSpA if they did not meet mNY criteria; to compared clinical, demographic, and laboratory test between the subgroups. It included 148 SpA patients; 55 (37.2%) patients had r-axSpA, and 70 (47.3%) had nr-axSpA. The nr-axSpA patients had a lower proportion of males (58.6% vs 78.2%, P < 0.05), lower HLA-B27 frequency (54.3%. vs. 92.7%, P < 0.05), were older at disease onset (21 vs 16 years; P < 0.01) and had a higher frequency of infections at disease onset (9.1% vs 32.9, P < 0.05) than r-axSpA. BASFI (2.9 vs 4.8; P < 0.0001), Dougados functional index (7 vs. 14; P < 0.05), and BASDAI (4.1 vs. 5.2; P < 0.001) were lower in patients with nr-axSpA than r-axSpA, respectively. The factors that most influenced the presentation of r-axSpA were history of uveitis (OR 14, 95% CI 2.3-85), HLA-B27 (OR 7.97, 95% CI, 2.96-122), male sex (OR 6.16, 95% CI, 1.47-25.7), axial enthesopathy count (OR 1.17 95% CI, 1.03-1.33). This study provides insight into the differences between nr-axSpA and r-axSpA in Mexico. Patients with r-axSpA were mainly male, with a younger presentation age, a higher prevalence of HLA-B27, more history of uveitis, fewer episodes of dactylitis, more axial enthesopathy, and higher disease activity than nr-axSpA.

CHOP-mediated IL-23 overexpression does not drive colitis in experimental spondyloarthritis.

HLA-B27 is a major risk factor for spondyloarthritis (SpA), yet the underlying mechanisms remain unclear. HLA-B27 misfolding-induced IL-23, which is mediated by endoplasmic reticulum (ER) stress has been hypothesized to drive SpA pathogenesis. Expression of HLA-B27 and human ß2m (hß2m) in rats (HLA-B27-Tg) recapitulates key SpA features including gut inflammation. Here we determined whether deleting the transcription factor CHOP (Ddit3-/-), which mediates ER-stress induced IL-23, affects gut inflammation in HLA-B27-Tg animals. ER stress-mediated Il23a overexpression was abolished in CHOP-deficient macrophages. Although CHOP-deficiency also reduced Il23a expression in immune cells isolated from the colon of B27+ rats, Il17a levels were not affected, and gut inflammation was not reduced. Rather, transcriptome analysis revealed increased expression of pro-inflammatory genes, including Il1a, Ifng and Tnf in HLA-B27-Tg colon tissue in the absence of CHOP, which was accompanied by higher histological Z-scores. RNAScope localized Il17a mRNA to the lamina propria of the HLA-B27-Tg rats and revealed similar co-localization with Cd3e (CD3) in the presence and absence of CHOP. This demonstrates that CHOP-deficiency does not improve, but rather exacerbates gut inflammation in HLA-B27-Tg rats, indicating that HLA-B27 is not promoting gut disease through ER stress-induced IL-23. Hence, CHOP may protect rats from more severe HLA-B27-induced gut inflammation.

A short review on deciphering Vyadhikshamatva: insights from HLA-B27-ankylosing spondylitis relation.

OBJECTIVES: Various aspects of the concept of Vyadhikshamatva have been thoroughly explored, highlighting its profound significance in resisting disease manifestation, particularly in the context of Ankylosing spondylitis. Investigated the relationship between HLA-B27 and Ankylosing spondylitis (AS) by examining current knowledge and hypotheses Furthermore, efforts were made to portray the influence of prakruti (constitution) and balam (strength) on disease manifestation and progression. METHODS: Ayurvedic literature along with contemporary research works was analyzed for correlating various aspects like vyadhikshamatva,oja (The final essence of all body elements), and balam along with their influence on the defensive mechanism of the body. A thorough literature search was conducted to explore the strong association between HLA-B27 and AS by examining various hypotheses like the Arthritogenic peptide hypothesis, the Misfolding hypothesis, the Surface Homodimer hypothesis, and the ß2 microglobulin hypothesis that attempts to explain the pathogenic role of HLA-B27 in AS. Alongside classical Ayurvedic texts, databases like PubMed and Scopus were searched using keywords such as Immunity, Ankylosing spondylitis, Vyadhikshamatva, HLA-B27, Balam, and Autoimmune disorder with the help of Boolean operators. RESULTS: The review highlighted the critical role of Vyadhikshamatva in disease prevention, particularly in influencing the manifestation of conditions like AS despite genetic predisposition (HLA-B27). Further, the understanding of the Ayurvedic concepts can clearly explain the conflict that has arisen in the determination of the positive HLAB27 gene in Ankylosing Spondylitis as a definite diagnosing criteria. CONCLUSIONS: This comprehensive understanding will uplift the need for personalized medicine in disease management. Further research must be needed to understand the interaction between genetic factors (HLAb27), individual constitution, and their vyadikshamatva.

Comparative study of two laboratory techniques for the detection of HLA-B27 in patients with axial spondyloarthritis: a cross-sectional analysis.

BACKGROUND: The diagnostic and prognostic relevance of Human Leukocyte Antigen B-27 (HLA-B27) in Axial Spondyloarthritis (AxSpA) is undeniable, with 70% of Ankylosing Spondylitis (AS) patients carrying the B27 gene, contrasted with a mere 4.35% in the general population. Flow cytometry (FC) and Polymerase Chain Reaction (PCR) have emerged as the predominant techniques for routine HLA-B27 typing. While various studies have compared these methods, none have catered to the unique characteristics of the Brazilian demographic. Therefore, this research aims to compare FC and PCR in a Brazilian cohort diagnosed with AxSpA. METHODS: An analytical cross-sectional study was undertaken involving 62 AxSpA outpatients from a Brazilian University Hospital. Both FC and PCR-SSP assays were utilized to ascertain HLA-B27 typing. The outcomes (either confirming or refuting the allele's presence) underwent rigorous scrutiny. Agreement between the methodologies was assessed using the kappa statistic. A p-value of < 0.05 was deemed statistically significant. RESULTS: Of the participants, 90.3% (n = 56) were HLA-B27 positive according to FC, while 79% (n = 49) were identified as positive using the PCR method. FC exhibited a sensitivity rate of 98% paired with a specificity of 38.5%. The Positive Predictive Value for FC stood at 85.7%, and the Negative Predictive Value was 83.5%. Consequently, the overall accuracy of the FC method was gauged at 85.5%. A kappa coefficient of κ = 0.454 was derived. CONCLUSIONS: FC demonstrated noteworthy sensitivity and satisfactory accuracy in HLA-B27 detection, albeit with a reduced specificity when contrasted with PCR-SSP. Nevertheless, given its cost-effectiveness and streamlined operation relative to PCR, FC remains a pragmatic option for preliminary screening in clinical practice, especially in low-income regions. To optimize resource allocation, we advocate for a refined algorithm that initiates by assessing the relevance of HLA-B27 typing based on Choosing Wisely recommendations. It then leans on FC, and, if results are negative yet clinical suspicion persists, advances to PCR. This approach aims to balance diagnostic accuracy and financial prudence, particularly in regions contending with escalating medical costs.

The gut microbiome and HLA-B27-associated anterior uveitis: a case-control study.

BACKGROUND: The human gut microbiome (GM) is involved in inflammation and immune response regulation. Dysbiosis, an imbalance in this ecosystem, facilitates pathogenic invasion, disrupts immune equilibrium, and potentially triggers diseases including various human leucocyte antigen (HLA)-B27-associated autoinflammatory and autoimmune diseases such as inflammatory bowel disease (IBD) and spondyloarthropathy (SpA). This study assesses compositional and functional alterations of the GM in patients with HLA-B27-associated non-infectious anterior uveitis (AU) compared to healthy controls. METHODS: The gut metagenomes of 20 patients with HLA-B27-associated non-infectious AU, 21 age- and sex-matched HLA-B27-negative controls, and 6 HLA-B27-positive healthy controls without a history of AU were sequenced using the Illumina NovaSeq 6000 platform for whole metagenome shotgun sequencing. To identify taxonomic and functional features with significantly different relative abundances between groups and to identify associations with clinical metadata, the multivariate association by linear models (MaAsLin) R package was applied. RESULTS: Significantly higher levels of the Eubacterium ramulus species were found in HLA-B27-negative controls (p = 0.0085, Mann-Whitney U-test). No significant differences in microbial composition were observed at all other taxonomic levels. Functionally, the lipid IVA biosynthesis pathway was upregulated in patients (p < 0.0001, Mann-Whitney U-test). A subgroup analysis comparing patients with an active non-infectious AU to their age- and sex-matched HLA-B27-negative controls, showed an increase of the species Phocaeicola vulgatus in active AU (p = 0.0530, Mann-Whitney U-test). An additional analysis comparing AU patients to age- and sex-matched HLA-B27-positive controls, showed an increase of the species Bacteroides caccae in controls (p = 0.0022, Mann-Whitney U-test). CONCLUSION: In our cohort, non-infectious AU development is associated with compositional and functional alterations of the GM. Further research is needed to assess the causality of these associations, offering potentially novel therapeutic strategies.

Comparison of clinical characteristics between patients with axial spondyloarthritis with and without acute anterior uveitis: a multicentre study of the Chinese Spondyloarthritis Registry.

OBJECTIVES: This study explores the clinical characteristics associated with the occurrence of acute anterior uveitis (AAU) in patients with axial spondyloarthritis (axSpA) within a large, multicentre database. METHODS: This observational, cross-sectional study of patients with axSpA used data from the Chinese Spondyloarthritis Registry between August 1, 2018, and March 31, 2020. The demographic and clinical features of patients with and without AAU were compared. Univariate and multivariate analyses were performed to determine the association between variables and uveitis. RESULTS: A total of 4304 patients were included in this study. The prevalence of AAU in patients with axSpA was 10.59%. Multivariate logistic regression analysis revealed a positive correlation between AAU and age at diagnosis (odds ratio [OR], 1.026; p<0.001), disease duration (OR, 2.117; p<0.001), current or past Achilles tendinitis (OR, 1.692; p<0.001), current or past dactylitis (OR, 1.687; p=0.002), current or past psoriasis (OR, 3.932; p<0.001), presence of human leukocyte antigen-B27 (HLA-B27) (OR, 2.787; p<0.001), and a good response to non-steroidal anti-inflammatory drugs (NSAIDs) (OR, 1.343; p=0.027). CONCLUSIONS: AAU was the most common extra-articular manifestation in the Chinese Spondyloarthritis Registry. In Chinese patients with axSpA, older age at diagnosis, longer disease duration, presence of HLA-B27, current or past Achilles tendinitis, current or past dactylitis, current or past psoriasis, and a good response to NSAIDs were positively associated with AAU.

A Cost-Effective and Labor-Saving Method for Detecting Human Leukocyte Antigen B27 Status via Sequence-Encoded Fluorescence Amplification Assay.

Identification of human leukocyte antigen B27 (HLA-B27) by flow cytometry (FCM) has been widely applied in clinical practice for auxiliary diagnosis of ankylosing spondylitis (AS). However, FCM requires freshly prepared samples and relies on expensive equipment, reagents, and an experienced operator. To provide a cheaper and more convenient method for HLA-B27 detection, we proposed a new method termed sequence-encoded fluorescence amplification assay (SEFA), which specially recognized sequences of HLA-B27 gene (HLA-B∗27) covering current common subtypes in a single closed tube. SEFA could detect as low as 10 pg (equal to 3 copies) genomic DNA per reaction and distinguish HLA-B∗27 from other HLA-B alleles with highly similar sequences. A total of 288 clinical samples were tested by SEFA, including 181 patients with AS and 107 healthy controls. Compared with the detection results from FCM, two controversial samples of patients with AS were obtained and further confirmed to be consistent with SEFA by Sanger sequencing, indicating that this method was more accurate than FCM. Moreover, SEFA could detect HLA-B27 status by using supernatant from crude extract of 10-µL blood without commercial reagents. Overall, SEFA has the potential to be an alternative for HLA-B27 identification with the advantage of convenience and low cost, especially suitable for early diagnosis of AS in areas with limited medical resources.

To be or not to B27 positive: implications for the phenotypes of axial spondyloarthritis outcomes. Data from a large multiracial cohort from the Brazilian Registry of Spondyloarthritis.

BACKGROUND: There is a remarkable variability in the frequency of HLA-B27 positivity in patients with spondyloarthritis (SpA), which may be associated with different clinical presentations worldwide. However, there is a lack of data considering ethnicity and sex on the evaluation of the main clinical and prognostic outcomes in mixed-race populations. The aim of this study was to evaluate the frequency of HLA-B27 and its correlation with disease parameters in a large population of patients from the Brazilian Registry of Spondyloarthritis (RBE). METHODS: The RBE is a multicenter, observational, prospective cohort that enrolled patients with SpA from 46 centers representing all five geographic regions of Brazil. The inclusion criteria were as follow: (1) diagnosis of axSpA by an expert rheumatologist; (2) age ≥18 years; (3) classification according to ASAS axial. The following data were collected via a standardized protocol: demographic data, disease parameters and treatment historical. RESULTS: A total of 1096 patients were included, with 73.4% HLA-B27 positivity and a mean age of 44.4 (±13.2) years. Positive HLA-B27 was significantly associated with male sex, earlier age at disease onset and diagnosis, uveitis, and family history of SpA. Conversely, negative HLA-B27 was associated with psoriasis, higher peripheral involvement and disease activity, worse quality of life and mobility. CONCLUSIONS: Our data showed that HLA-B27 positivity was associated with a classic axSpA pattern quite similar to that of Caucasian axSpA patients around the world. Furthermore, its absence was associated with peripheral manifestations and worse outcomes, suggesting a relevant phenotypic difference in a highly miscegenated population.

Long-term follow-up of 109 children with juvenile idiopathic oligoarthritis after first intra-articular corticosteroid injection.

BACKGROUND: To evaluate long-term outcomes and prognostic factors in patients with juvenile idiopathic arthritis (JIA), presenting as oligoarthritis, who received IAC as the first treatment for their disease. METHODS: We conducted retrospective study at the University Children's Hospital Ljubljana, Slovenia, from January 2015 to May 2023 in children with JIA, clinically presenting as oligoarthritis receiving intra-articular corticosteroid injection (IAC) as the initial treatment. Patient and treatment data were collected, and the outcomes were categorized into three groups based on the later need for therapy: no therapy needed, only additional IAC needed and systemic therapy needed. The last group was further divided based on the requirement of bDMARD. Log-rank (Mantel-Cox) survival analyses compared different outcome groups. RESULTS: We included 109 patients with JIA, presenting as oligoarthritis (63% female), who were first treated with IAC. The mean age at IAC was 8.0 years, with a 4.3-year follow-up. Notably, 38.5% of patients did not require additional therapy post-IAC, whereas 15.5% required only additional IAC. Systemic therapy, mainly methotrexate (MTX), was necessary for 45.9% of patients, initiated in average 7.8 months post-IAC. Biologic therapy was initiated in 22% in average 2.2 years post-IAC. Number of injected joints correlated with the need for biologics. At the last follow-up, 88.9% had inactive disease. ANA positivity (P = 0.049, chi square 3.89) and HLA B27 antigen presence (P = 0.050, chi square 3.85) were associated with the need for systemic therapy. A subgroup of children older than 8 years, ANA and HLA B27 negative required significantly less systemic (25.8%) and biologic therapy (9.6%) compared to other patients (p = 0.050, chi square 3.77). CONCLUSION: Almost 40% of children with oligoarticular JIA requiring IAC did not progress to chronic disease. Younger age, ANA positivity, and HLA B27 presence were predictive factors for systemic therapy, while the number of injected joints predicted the future need for biologic therapy.

Clinical, Laboratory, and Imaging Features Between Men and Women With Axial Spondyloarthritis in a Specialized Center in Argentina.

OBJECTIVES: The aims were to estimate the frequency of axial spondyloarthritis (axSpA) in women and to analyze the clinical, laboratory, and imaging differences with respect to men at the time of diagnosis. METHODS: Consecutive patients older than 18 years with a diagnosis of axSpA admitted to the "Reumacheck" SpA program were included between 2017 and 2022. At baseline, all patients underwent clinical assessment, laboratory tests including C-reactive protein and human leukocyte antigen B27, and imaging (plain radiography and magnetic resonance imaging of sacroiliac joints, and ultrasound of heel entheses). All evaluators were blinded to the results of the other evaluations. RESULTS: One hundred sixteen patients with a diagnosis of axSpA were included. The frequency at diagnosis in women was 61.55%. In the univariate analysis, the significant differences between women and men at diagnosis of axSpA were good response to nonsteroidal anti-inflammatory drugs, elevated C-reactive protein, New York Criteria (+), enthesis ultrasound (+), years of education, number of swollen joints, erythrosedimentation rate, and the very low frequency of bone bridges in the magnetic resonance imaging of the sacroiliac joints. In the logistic regression analysis, the dependent variable was "men," and the only feature that was independently associated was having radiographic compromise according to the New York criteria (odds ratio, 2.6). CONCLUSIONS: The frequency of axSpA in women was 61.55%; clinical, laboratory, and imaging differences were observed. Women experienced less radiographic compromise.

Correlation of TBX21 gene polymorphisms with ankylosing spondylitis in a Chinese population.

Genome-wide association studies analysis has revealed associations between ankylosing spondylitis (AS) and loci on the TBX21 gene across various populations. This study aimed to investigate if there is a connection between a higher risk of AS in a Chinese population and two polymorphism loci on the TBX21 gene. To achieve this, we performed a case-control investigation involving 363 patients with AS and 907 healthy individuals. Genotyping was carried out using the iPLEX Gold genotyping assay. The analysis of genotypes and haplotypes was performed using SPSS 23.0 and SHEsis software. The results revealed no statistically significant correlation between the two specified single-nucleotide polymorphisms of TBX21 (rs11657479 C/T and rs4794067 C/T) and susceptibility to AS. However, upon conducting stratification analysis, our findings demonstrated a significant association between rs11657479 and susceptibility to human leucocyte antigen (HLA)-B27+ AS in allelic (C vs. T: odds ratio [OR] = 1.52, 95%CI = 1.09-2.11, corrected p [pc] = .028), heterozygous (CT vs. TT: OR = 1.63, 95%CI = 1.13-2.34, pc = .016) and dominant (CT + CC vs. TT: OR = 1.60, 95%CI = 1.12-2.28, pc = .018) models. Furthermore, the haplotype rs4794067/C-rs11657479/C of TBX21 was found to increase the risk of HLA-B27+ AS cases. In conclusion, our findings indicate a correlation between TBX21 gene polymorphism and HLA-B27+ AS patients within the Chinese population.

Investigation of the acute pathogenesis of spondyloarthritis/HLA-B27-associated anterior uveitis based on genome-wide association analysis and single-cell transcriptomics.

BACKGROUND: Patients with spondyloarthritis (SpA)/HLA-B27-associated acute anterior uveitis (AAU) experience recurring acute flares, which pose significant visual and financial challenges. Despite established links between SpA and HLA-B27-associated AAU, the exact mechanism involved remains unclear, and further understanding is needed for effective prevention and treatment. METHODS: To investigate the acute pathogenesis of SpA/HLA-B27-associated AAU, Mendelian randomization (MR) and single-cell transcriptomic analyses were employed. The MR incorporated publicly available protein quantitative trait locus data from previous studies, along with genome-wide association study data from public databases. Causal relationships between plasma proteins and anterior uveitis were assessed using two-sample MR. Additionally, colocalization analysis was performed using Bayesian colocalization. Single-cell transcriptome analysis utilized the anterior uveitis dataset from the Gene Expression Omnibus (GEO) database. Dimensionality reduction, clustering, transcription factor analysis, pseudotime analysis, and cell communication analysis were subsequently conducted to explore the underlying mechanisms involved. RESULTS: Mendelian randomization analysis revealed that circulating levels of AIF1 and VARS were significantly associated with a reduced risk of developing SpA/HLA-B27-associated AAU, with AIF1 showing a robust correlation with anterior uveitis onset. Colocalization analysis supported these findings. Single-cell transcriptome analysis showed predominant AIF1 expression in myeloid cells, which was notably lower in the HLA-B27-positive group. Pseudotime analysis revealed dendritic cell terminal positions in differentiation branches, accompanied by gradual decreases in AIF1 expression. Based on cell communication analysis, CD141+CLEC9A+ classic dendritic cells (cDCs) and the APP pathway play crucial roles in cellular communication in the Spa/HLA-B27 group. CONCLUSIONS: AIF1 is essential for the pathogenesis of SpA/HLA-B27-associated AAU. Myeloid cell differentiation into DCs and decreased AIF1 levels are also pivotal in this process.

Profile of HLA-B27-positive enthesitis/spondylitis-related arthritis in Senegal, West Africa.

BACKGROUND: Enthesitis/spondylitis-related arthritis (ERA) is a type of juvenile idiopathic arthritis (JIA) frequently associated with HLA-B27. In sub-Saharan Africa, HLA-B27-positive ERA hasn't been the subject of a specific study. OBJECTIVES: We aimed to describe the clinical features, disease activity, functional disability and treatment of HLA-B27-positive ERA at diagnosis in Senegal and compare the findings to other populations. METHODS: We conducted a retrospective study by reviewing the medical records of patients diagnosed with ERA with an age of symptom onset < 18 years according to the 2019 PRINTO provisional criteria for ERA from January 2012 to December 2022. We collected demographic, clinical, paraclinical and therapeutic data. Disease activity score was assessed by Ankylosing Spondylitis Disease Activity Score (ASDAS) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Functional disability was assessed using Bath Ankylosing Spondylitis Functional Index (BASFI). RESULTS: A total of 31 patients with HLA-B27-positive ERA were included. Twenty of 31 (64.5%) were males. Twenty-seven (87%) were Fula (ethnicity). The median age at symptom onset and at diagnosis was 12 years and 19 years, respectively. Seven patients had a family history of Spondyloarthritis. Peripheral arthritis and enthesitis were the most common presenting features at disease onset. Peripheral arthritis was present in 29 (93.5%) and located in the lower limbs in 27/29 (93.1%) patients. Heel enthesitis was present in 26 (83.8%) patients. Axial involvement was present in 27 (87%) patients, dominated by low back pain and sacroiliac pain/ buttock pain in 24 (88.8%) and 22 (81.5%) patients, respectively. Seven (22.5%) patients had anterior uveitis. The ESR and CRP were elevated in 65.5% and 57.1% of cases, respectively. On imaging, sacroiliitis was found in 22 patients. The mean BASDAI was 5.5/10 (77.2% of patients had a high active disease; BASDAI ≥ 4/10). The mean ASDAS-ESR/CRP was 3.8. The mean BASFI was 5.4/10 (80% of patients had high functional disability; BASFI ≥ 4/10). Twenty-seven (87%) patients were treated with methotrexate and non-steroidal anti-inflammatory drugs. After 6 months of treatment, mean BASDAI was 3/10 and mean BASFI was 2.5/10. CONCLUSION: In our study, HLA-B27-positive ERA was found in our Senegalese cohort mainly in adolescents of the Fula ethnic group. 22 (70.9%) patients developed ankylosing spondylitis at adulthood. The disease was very active at the time of diagnosis with significant functional disability. Treatment was mainly based on methotrexate and NAISDs.

How to translate genetic findings into clinical applications in spondyloarthritis?

Spondyloarthritis (SpA) is characterized by a strong genetic predisposition evidenced by the identification of up to 50 susceptibility loci, in addition to HLA-B27, the major genetic factor associated with the disease. These loci have not only deepened our understanding of disease pathogenesis but also offer the potential to improve disease management. Diagnostic delay is a major issue in SpA. HLA-B27 testing is widely used as diagnostic biomarker in SpA but its predictive value is limited. Several attempts have been made to develop more sophisticated polygenic risk score (PRS). However, these scores currently offer very little improvement as compared to HLA-B27 and are still difficult to implement in clinical routine. Genetics might also help to predict disease outcome including treatment response. Several genetic variants have been reported to be associated with radiographic damage or with poor response to TNF blockers, unfortunately with lack of coherence across studies. Large-scale studies should be conducted to obtain more robust findings. Genetic and genomic evidence in complex diseases can be further used to support the identification of new drug targets and to repurpose existing drugs. Although not fully driven by genetics, development of IL-17 blockers has been facilitated by the discovery of the association between IL23R variants and SpA. Development of recent approaches combining GWAS findings with functional genomics will help to prioritize new drug targets in the future. Although very promising, translational genetics in SpA remains challenging and will require a multidisciplinary approach that integrates genetics, genomics, immunology, and clinical research.

Changes in HLA-B27 Transgenic Rat Fecal Microbiota Following Tofacitinib Treatment and Ileocecal Resection Surgery: Implications for Crohn's Disease Management.

The therapeutic management of Crohn's disease (CD), a chronic relapsing-remitting inflammatory bowel disease (IBD), is highly challenging. Surgical resection is sometimes a necessary procedure even though it is often associated with postoperative recurrences (PORs). Tofacitinib, an orally active small molecule Janus kinase inhibitor, is an anti-inflammatory drug meant to limit PORs in CD. Whereas bidirectional interactions between the gut microbiota and the relevant IBD drug are crucial, little is known about the impact of tofacitinib on the gut microbiota. The HLA-B27 transgenic rat is a good preclinical model used in IBD research, including for PORs after ileocecal resection (ICR). In the present study, we used shotgun metagenomics to first delineate the baseline composition and determinants of the fecal microbiome of HLA-B27 rats and then to evaluate the distinct impact of either tofacitinib treatment, ileocecal resection or the cumulative effect of both interventions on the gut microbiota in these HLA-B27 rats. The results confirmed that the microbiome of the HLA-B27 rats was fairly different from their wild-type littermates. We demonstrated here that oral treatment with tofacitinib does not affect the gut microbial composition of HLA-B27 rats. Of note, we showed that ICR induced an intense loss of bacterial diversity together with dramatic changes in taxa relative abundances. However, the oral treatment with tofacitinib neither modified the alpha-diversity nor exacerbated significant modifications in bacterial taxa induced by ICR. Collectively, these preclinical data are rather favorable for the use of tofacitinib in combination with ICR to address Crohn's disease management when considering microbiota.