Diagnostic delay and its associated factors in Chinese axial spondyloarthritis: A single-center study of 1295 patients.

AIM: To delineate the landscape of diagnostic delay in Chinese axial spondyloarthritis (axSpA), investigate its associated factors, and explore its potential impact on medication modalities. METHODS: A total of 1295 patients fulfilling the ASAS classification criteria were obtained. Demographic and clinical data were collected through face-to-face interviews, based on predesigned questionnaires and available medical records. Logistic regression analyses under univariate and multivariable model were performed, using the median of diagnostic delay as the cut-off point for group classification. Differences between early- and late-diagnosed groups were subsequently compared by the Pearson chi-square test or Mann-Whitney U test. RESULTS: Of 1295 axSpA patients, 80.3% were male and the median of disease duration was 8.0 years. The median (IQR) diagnostic delay in Chinese axSpA was 3.0 (1.0 ~ 7.0) years and 24.8% of them reported a history of misdiagnosis. Older age at onset (OR = 0.97, p < .001) and higher education attainment (p = .001) were correlated with early diagnosis of axSpA, whereas coming from less developed areas (p = .002), a history of peripheral arthritis at the time of diagnosis (OR = 1.58, p = .002) and history of misdiagnosis (OR = 1.98, p < .001) increased the risk of diagnostic delay. Oral medication modalities were similar between two groups, but the proportion with no medication ever was higher in the late-diagnosed group (26.5% vs. 20.7%, p = .02). CONCLUSION: Our findings depicted a detailed spectrum of diagnostic delay in Chinese axSpA, verified five associated factors that may help facilitate timely diagnosis of axSpA, and pinpointed that timely medication was unsatisfying, especially in the late diagnosis group.

Integrative blood-derived epigenetic and transcriptomic analysis reveals the potential regulatory role of DNA methylation in ankylosing spondylitis.

BACKGROUND: The currently known risk loci could explain a small proportion of the heritability of ankylosing spondylitis (AS). Epigenetics might account for the missing heritability. We aimed to seek more novel AS-associated DNA methylation alterations and delineate the regulatory effect of DNA methylation and gene expression with integrated analysis of methylome and transcriptome. METHODS: Epigenome-wide DNA methylation and mRNA expression were profiled in peripheral blood mononuclear cells (PBMCs) from 45 individuals (AS: health controls (HCs) = 30:15) with high-throughput array. The methylome was validated in an independent cohort (AS: HCs = 12:12). Pearson correlation analysis and causal inference tests (CIT) were conducted to determine potentially causative regulatory effects of methylation on mRNA expression. RESULTS: A total of 4794 differentially methylated positions (DMPs) were identified associated with AS, 2526 DMPs of which were validated in an independent cohort. Both cohorts highlighted T cell receptor (TCR) signaling and Th17 differentiation pathways. Besides, AS patients manifested increased DNA methylation variability. The methylation levels of 158 DMPs were correlated with the mRNA expression levels of 112 genes, which formed interconnected network concentrated on Th17 cell differentiation and TCR signaling pathway (LCK, FYN, CD3G, TCF7, ZAP70, CXCL12, and PLCG1). We also identified several cis-acting DNA methylation and gene expression changes associated with AS risk, which might regulate the cellular mechanisms underlying AS. CONCLUSIONS: Our studies outlined the landscapes of epi-signatures of AS and several methylation-gene expression-AS regulatory axis and highlighted the Th17 cell differentiation and TCR signaling pathway, which might provide innovative molecular targets for therapeutic interventions for AS.

Adalimumab Therapy Restores the Gut Microbiota in Patients With Ankylosing Spondylitis.

Growing evidence suggests that the gut microbiota is involved in the initiation and progression of ankylosing spondylitis (AS). In this study, we aimed to explore the gut microbiome alterations during adalimumab therapy and verify microbiome biomarkers predicting treatment response. By evaluating the gut microbial features of 30 AS patients before and after adalimumab therapy for 6 months and 24 healthy controls, we confirmed that the microbiome was restored remarkably after 6 months of adalimumab therapy in AS patients. We then compared the baseline gut microbiome of 22 adalimumab responders with 8 non-responders, a higher abundance of Comamonas was revealed in the latter, although no statistical difference was found after adjusting for the false discovery rate. These results suggested that adalimumab therapy restored the gut microbiome in AS patients and indicated the utility of gut microbiome to be potential biomarkers for therapeutic evaluation. These findings provided an insight into the development of predictive tools and the establishment of precise medical interventions for clinical practice.

Circulating Retinol-Binding Protein 4 as a Possible Biomarker of Treatment Response for Ankylosing Spondylitis: An Array-Based Comparative Study.

OBJECTIVE: To explore proteins associated with ankylosing spondylitis (AS) and to investigate potential proteins that may predict treatment response of adalimumab (ADA) in AS patients. METHODS: In the discovery cohort, 39 AS patients and 20 healthy controls (HCs) were included, and 16 AS patients received ADA treatment for 24 weeks after included. In the validation cohort, 43 AS patients and 39 HCs were enrolled, and all 43 patients received ADA treatment after enrollment. Blood samples and clinical information were collected from two cohorts at baseline from all participants and week 24 from patients received ADA treatment. A human antibody array containing 1,000 proteins was used in the discovery phase, and Elisa kits were used for protein validation. RESULTS: Compared with HCs, we identified 53 differentially expressed proteins (DEPs) in AS patients. Bioinformatics analysis revealed they were mostly enriched in coagulation function-related pathways, acute response signaling, and LXR/RXR activation. Bone metabolism pathways were also associated. Comparison between samples of pre- and post-ADA treatment revealed 42 DEPs. They were mostly associated with bone metabolism and inflammation response pathways. Significant enrichment was also found in LXR/RXR activation but not the coagulation function-related pathways. Upstream regulator analysis suggested that most regulators also significantly functioned under usage of ADA. Precisely, seven proteins were abnormally expressed in AS and restored after ADA treatment. Retinol-binding protein 4 (RBP4), one of the seven proteins, was validated that its baseline levels were inversely correlated with improvements in Ankylosing Spondylitis Disease Activity Score-C-reactive protein (ASDAS-CRP). Likewise, percentage changes in RBP4 levels were inversely correlated with changes in ASDAS-CRP score. CONCLUSION: A dysregulated serum protein profile existed in AS. ADA exerted a considerable but not entire alteration toward the dysregulation. RBP4 could be a biomarker for predicting and monitoring ADA treatment response.

The Clinical Characteristics of Other HLA-B Types in Chinese Ankylosing Spondylitis Patients.

HLA-B27 has an established relationship with the development of ankylosing spondylitis (AS). After reviewing the HLA-B genotype from 407 Chinese subjects (318 patients and 89 sex-matched controls), we found that 252 patients and 32 controls were HLA-B27(+) and that HLA-B*27:04 was the dominant HLA-B27 subtype (N = 224). In all participants, HLA*27:04 homozygous were only detected in two patients. In the HLA-B27(+) group, HLA-B40 was observed in 51 cases and one control (p < 0.05, OR = 7.87, 95% CI 1.05-59.0); of these, the most genotype was HLA-B*27:04/B*40:01(N = 38). Two hundred thirty-nine patients' clinical information was recorded. Cases with HLA-B27/B46 had more peripheral joint involvement (OR = 3.95, 95% CI 1.77-8.79) in HLA-B27(+) AS. HLA-B*15:02 may be a significant risk element to peripheral joint involvement (p < 0.05) in HLA-B27(-) patients. Therefore, we believe HLA-B*40:01, HLA-B*46:01, and HLA-B*15:02 can be the test indicators for AS diagnostic value.

Age-Specific Imbalance of Circulating Tfh Cell Subsets and Its Association With Gout-Targeted Kidney Impairment.

Objective: Gout is a chronic disease characterized by the deposition of monosodium urate (MSU) crystals in tissue. Study with a focus on adaptive immune response remains to be understood although innate immune response has been reported extensively in gout etiology. Our study attempted to investigate the association of gout-related immune cell imbalance with clinical features and comorbidity with renal impairment and the implicated pathogenesis via the assessment of T and B cell subsets in different activity phases or with immune effects combined with the analyses of clinical parameters. Methods: Fifty-eight gout patients and 56 age- and sex-matched healthy individuals were enrolled. To learn the roles of circulating T cells, a lymphocyte profile incorporating 32 T cell subsets was tested from isolated freshly peripheral blood monocyte cells (PBMCs) with multiple-color flow cytometry. Furthermore, the collected clinical features of participants were used to analyze the characteristics of these differential cell subsets. Stratified on the basis of the level of creatinine (Cr, enzymatic method), all patients were categorized into Crlow (Cr ≤ 116 µmol/L) and Crhi (Cr > 116 µmol/L) groups to exploit whether these gout-associated T cell subsets were functional in gout-targeted kidney dysfunction. The differentiation of B cells was investigated in gout patients. Results: Our results show that CD 4+ T cells, Th2 cells, and Tc2 cells were upregulated, whereas Tc17 cells were downregulated. Tfh cells skewed toward the polarization of Tfh2 cells. Specifically, Tfh2 cells increased, but Tfh1 cells decreased, accompanied with aging for gout patients, suggesting that age might trigger the skewing of Tfh1/Tfh2 cell subsets to influence gout development. Moreover, Tfh2 cells were connected to renal dysfunction as well. No alterations of B cell subsets were observed in patients when compared to controls. Conclusions: Our data demonstrate age-specific dysfunctions of Tfh1/2 cells in gout occurrence, and Tfh2 cell upregulation is associated with gout-targeted renal dysfunction. However, Tfh2 cells may function in auto-inflammatory gout independent of helping B differentiation, and an in-depth study remains to be conducted.

Analysis of 47 Non-MHC Ankylosing Spondylitis Susceptibility Loci Regarding Associated Variants across Whites and Han Chinese.

OBJECTIVE: To present a systematic evaluation of 47 non-MHC ankylosing spondylitis (AS) susceptibility loci that have been initially discovered through white genome-wide association studies in Han Chinese. METHODS: Originally, 10,743 samples representing north and south Chinese in 4 datasets were obtained. After data quality control and imputation, metaanalysis results of 94,621 variants within 47 loci were extracted. Four ERAP1 single-nucleotide polymorphisms (SNP) and HLA-B27 tag SNP rs13202464 were used for interaction analysis. Population-attributable risk percentages of AS-associated variants were compared. Functional annotations of AS-associated variants were conducted using HaploReg, RegulomeDB, and rVarBase databases. RESULTS: We revealed 16 AS-associated variants with nominal evidence in Han Chinese, including rs10865331 (p = 6.30 × 10-10), rs10050860 (p = 4.09 × 10-5) and rs8070463 (p = 1.03 × 10-4). Potential susceptible SNP within these 47 loci were also identified, such as rs13024541 (2p15), rs17401719 (5q15), and rs62074054 (17q21). Epistatic interactions between 3 ERAP1 SNP (rs17401719, rs30187, and rs10050860) and HLA-B27 were confirmed. Among the 16 AS-associated variants, rs30187 showed weaker risk effect, while rs10050860 and rs12504282 seemed to attribute more risk in Han Chinese than in whites. Further genomic annotation pinpointed 35 candidate functional SNP, especially in the 2p15, ERAP1, and NPEPPS-TBKBP1 regions. CONCLUSION: Our results provided a detailed spectrum of all the reported non-MHC AS susceptibility loci in Han Chinese, which comprehensively exhibited the ethnic heterogeneity of AS susceptibility and highlighted that 2p15, ERAP1, and NPEPPS-TBKBP1 regions may play a critical role in AS pathogenesis across diverse populations.

Variations in gut microbial profiles in ankylosing spondylitis: disease phenotype-related dysbiosis.

BACKGROUND: Microbial involvement in ankylosing spondylitis (AS) has been suggested; however, the relationship between gut microbiome and the disease phenotypes of AS remains to be established. This study was to characterize and investigate differences in the gut microbiome between AS patients and healthy controls (HCs), and to determine whether the gut microbiome profile associated with the disease phenotypes. METHODS: 16S rRNA gene V4 region sequencing was performed on fecal DNA isolated from stool samples collected from 41 patients with AS [20 axial AS (axAS) and 21 peripheral AS (pAS)] and 19 HCs. QIIME based pipeline was used to process the raw sequence data. Alpha and beta diversities were assessed using QIIME, and comparisons of gut microbiome profile were performed using linear discriminant analysis (LDA) effect size (LEfSe) to examine differences between groups and subgroups. A gut microbiota-based model for predictive diagnosis of AS was constructed using random forest algorithm and its predictive value was assessed by receiver-operating characteristic analyses. RESULTS: Our results showed that fecal microbial communities in patients with AS differ significantly from those in HCs, driven by a higher abundance of 7 genera (Prevotella_9, Dialister, Comamonas, Collinsella, Streptococcus, Alloprevotella and Prevotella_2) and a lower abundance of 4 genera (Eubacterium_ruminantium_group, Ruminococcus_gnavus_group, Lachnospira and Bacteroides). In addition, pAS patients were more enriched in Comamonas, Streptococcus and Collinsella, while axAS patients were more enriched in Prevotella_2. An 8 genera-based model showed high accuracy for distinguishing AS patients from HCs with an area under the curve (AUC) up to 0.950. CONCLUSIONS: Our results revealed specific alterations in the gut microbiome in patients with different phenotypes of AS, and the classification model based on gut microbial features might provide a new direction for future clinical diagnosis. Lastly, discovery of the associated microbes of AS in the gut microbiome may help us to seek more treatments for this disease.

Spondyloarthritis Patients Suffer Increased Risk of Renal Complications Compared With General Population: A Retrospective Observational Study.

The objective of this study was to identify the prevalence and risk factors of renal complications of spondyloarthritis (SpA) patients, and to assess increased risks compared to general people. We conducted a retrospective study enrolled with consecutive SpA patients from an inpatient department and age, sex-matched general population (GP). The renal disorders investigated in this study contained decreased estimated glomerular filtration rate (eGFR), hematuria, proteinuria and nephrolithiasis. A total of 350 admitted SpA patients with complete medical records and 323 age and sex-matched GP were enrolled. Most SpA patients were male (n = 283, 80.9%) and the mean age was 31.61 ± 10.73 years old. Among 350 SpA patients, 29 (8.8%) suffered from hematuria, six (1.8%) suffered from proteinuria, one (0.3%) had decreased eGFR, and 27 (13.0%) presented with nephrolithiasis. The relative risk (RR) of nephrolithiasis in SpA compared to the GP was 2.24 (95% CI, 1.00-4.98), and the RR of renal insufficiency was 2.04 (95% CI, 1.11-3.77). In a univariate analysis, nephrolithiasis was significantly associated with age, age of onset, smoking, extra-articular manifestation and a bamboo spine. Renal insufficiency was significantly associated with age, peripheral manifestation, serum albumin, C-reactive protein and erythrocyte sedimentation rate. In a multivariable analysis, only extra-articular manifestation (OR = 8.43, 95% CI, 1.65-43.06, p = 0.010) and bamboo spine (OR = 3.47, 95% CI, 1.01-12.06, p = 0.049) remained significantly associated with nephrolithiasis. However, no variable was recognized as an independent risk factor for renal insufficiency. Renal complications are more common in SpA patients, with more than two-fold increased risk compared with GP. Extra-articular manifestation and bamboo spine are independent risk factors of renal disease in SpA patients.

Chinese patients' preference for pharmaceutical treatments of osteoporosis: a discrete choice experiment.

While adherence to osteoporosis treatment is low, patients' preference for osteoporosis treatment is unknown in Chinese patients. Chinese patients are willing to receive treatments with higher clinical efficacy and lower out-of-pocket cost. In addition, annual intravenous infusion and 6-month subcutaneous injection are preferred over weekly oral tablets. PURPOSE: This study was performed to elicit Chinese patients' preferences for osteoporosis medication treatment and to investigate the heterogeneities of the preferences in subgroups. METHODS: A discrete choice experiment comprising 15 choice sets with 4 important attributes was conducted in a Chinese population at risk of osteoporotic fracture. The four attributes were treatment efficacy in reducing the risk of fracture, out-of-pocket cost per year, adverse effects of treatment, and mode of administration. The patients were asked to choose between two hypothetical treatments; they could also choose no treatment. Mixed logit models were used, and any observed heterogeneity in the patients' preferences was further assessed in subgroup analyses. RESULTS: In total, 267 patients were analysed. On average, the patients preferred to receive treatment rather than no treatment. The patients preferred treatment with higher efficacy in preventing fracture and lower out-of-pocket cost. The least preferred adverse effect of medication was gastrointestinal disorders, followed by flu-like symptoms and finally skin reactions. The most preferred mode of administration was annual intravenous infusion, followed by 6-month subcutaneous injection, a weekly oral tablet, and daily nasal spray; daily oral tablets ranked as the least preferred mode of administration. The differences in the patients' preferences among all attributes were statistically significant (p < 0.05). Patients' age was found to contribute to the observed preference heterogeneity in most of the included attributes. CONCLUSIONS: This study revealed Chinese patients' preferences for osteoporosis treatments. Annual intravenous infusion and 6-month subcutaneous injection were significantly preferred over weekly oral tablets in this Chinese population.

Association between vitamin D receptor gene polymorphism and ankylosing spondylitis in Han Chinese.

OBJECTIVES: To investigate whether vitamin D receptor (VDR) gene polymorphisms confer susceptibility to aankylosing spondylitis (AS) and study its polymorphisms in Han Chinese. METHODS: We screened single nucleotide polymorphisms (SNPs) in the VDR region through genome-wide genotyping chips in AS cases and healthy controls, then used the exome sequencing result to analyze all the potential AS-associated SNPs in the VDR gene. RESULTS: Thirty-two SNPs were found in the VDR gene in the genome-wide genotyping chips and the logistic regression result showed no significant difference between AS cases and controls. A total of 46 SNPs in the VDR region were genotyped through exome sequencing, including four functional SNPs (rs731236 [TaqI], rs2228570 [FokI], rs7975232 [ApaI], rs1544410 [BsmI]) and two newly discovered SNPs (12:48259222 and 12:48276730). To note, rs731236 and rs2228570 locate in the exons of VDR, which cause synonymous and missense mutation. The association test showed there was no significant difference between AS cases and controls in the allele frequency distribution, but haplotype analysis of rs11168266-rs11168267 show nominal significance (P = 0.01268). CONCLUSION: Our preliminary study indicates the haplotypes (TG) of rs11168266-rs11168267 in the VDR gene confers susceptibility to AS, which is worth further research.