Serum Metabolomics Signatures Associated With Ankylosing Spondylitis and TNF Inhibitor Therapy.

Ankylosing spondylitis (AS) is a type of spondyloarthropathies, the diagnosis of which is often delayed. The lack of early diagnosis tools often delays the institution of appropriate therapy. This study aimed to investigate the systemic metabolic shifts associated with AS and TNF inhibitors treatment. Additionally, we aimed to define reliable serum biomarkers for the diagnosis. We employed an untargeted technique, ultra-performance liquid chromatography-mass spectroscopy (LC-MS), to analyze the serum metabolome of 32 AS individuals before and after 24-week TNF inhibitors treatment, as well as 40 health controls (HCs). Multivariate and univariate statistical analyses were used to profile the differential metabolites associated with AS and TNF inhibitors. A diagnostic panel was established with the least absolute shrinkage and selection operator (LASSO). The pathway analysis was also conducted. A total of 55 significantly differential metabolites were detected. We generated a diagnostic panel comprising five metabolites (L-glutamate, arachidonic acid, L-phenylalanine, PC (18:1(9Z)/18:1(9Z)), 1-palmitoylglycerol), capable of distinguishing HCs from AS with a high AUC of 0.998, (95%CI: 0.992-1.000). TNF inhibitors treatment could restore the equilibrium of 21 metabolites. The most involved pathways in AS were amino acid biosynthesis, glycolysis, glutaminolysis, fatty acids biosynthesis and choline metabolism. This study characterized the serum metabolomics signatures of AS and TNF inhibitor therapy. We developed a five-metabolites-based panel serving as a diagnostic tool to separate patients from HCs. This serum metabolomics study yielded new knowledge about the AS pathogenesis and the systemic effects of TNF inhibitors.

TNF-α inhibitor therapy can improve the immune imbalance of CD4+ T cells and negative regulatory cells but not CD8+ T cells in ankylosing spondylitis.

BACKGROUND: Studies into ankylosing spondylitis (AS) and its relationship with immune imbalance are controversial, and the correlation between the efficacy of TNF-α inhibitor and changes in immune imbalance is unclear. METHODS: A total of 40 immune cells were tested with flow cytometry, and the results of 105 healthy control (HC) subjects, 177 active-stage AS patients, and 23 AS cases before and after 12 weeks of TNF-α inhibitor therapy (Anbainuo) were analyzed. RESULTS: Compared with the HC group, the proportion of immune cells, such as naïve and central memory CD4+T cells, in AS increased (P < 0.0001), but effector memory and terminally differentiated CD4+T cells were decreased (P < 0.01 and 0.0001, respectively). Naïve, central memory, and effector memory CD8+T cells were increased (P < 0.0001, 0.001, and 0.01, respectively), but terminally differentiated CD8+T cells were decreased (P < 0.0001). Th1 cells (helper T cells-1), Tfh1 cells (follicular helper T cells-1), Tc1 cells (cytotoxic T cells-1), and Tregs (regulatory T cells) were lower (P < 0.01, 0.05, 0.0001, and 0.001, respectively), but Th17 cells, Tfh17 cells, and Tc cells were higher (P < 0.001, 0.0001, and 0.001, respectively). The proportions of total B cells and class-switched B cells were increased (P < 0.05), but non-switched B cells, plasma cells, memory B cells, and immature Bregs (regulatory B cells) were lower (P < 0.01, 0.0001, 0.0001, and 0.0001, respectively). After Anbainuo therapy, the percentage of naïve CD4+ T cells had decreased (P < 0.05) but Tregs and B10 cells (IL-10-producing regulatory B cells) had increased (P < 0.01 and 0.05, respectively), and the increase in Tregs was positively correlated with the decrease in C-reactive protein (CRP) (r = 0.489, P = 0.018). CONCLUSIONS: We found that active-stage AS patients have an immunity imbalance of frequency involving multiple types of immune cells, including CD4+T cells, CD8+T cells, Th cells, Tfh cells, Tc cells, Tregs, Bregs, and B cells. TNF-α inhibitor Anbainuo can not only help to inhibit disease activity but can also improve the immune imbalance of CD4+ T cells and negative regulatory cells in frequency. But CD8+ T cells have not been rescued.

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.

Prevalence of comorbidities and evaluation of screening in Chinese patients with spondyloarthritis.

The aim of the study was to determine whether the presence of spondyloarthritis (SpA) is associated with particular comorbidities and evaluate the prevalence of comorbidities, risk factors, and monitoring status in China. Three hundred forty-six patients fulfilling ASAS criteria for SpA were recruited from the Third Affiliated Hospital of Sun Yat-sen University. The prevalence of comorbidities and percentage of patients optimally monitored for comorbidities were calculated. The most frequent comorbidities were osteoporosis (31.0%) and hepatitis B virus infection (18.5%). Only 1 patient was found to have active tuberculosis. Several cancer screenings were performed in very few patients. Among 45 patients ever exposed to a biological DMARDs, 35 (77%) and 36 (80%) underwent a screening test for viral hepatitis and tuberculosis. Among patients without a history of hypertension, elevated blood pressure was detected in 5.8% of the patients. Hyperglycemia and hyperlipidemia were also found in patients during the study. One hundred twenty-two (35.3%) of the 346 patients never had either calcium or vitamin D for prevention of osteoporosis. Patients with SpA have high risks of comorbidities but have not monitored properly. More attention should be paid for systematic screening and an early detection of comorbidities in patients with SpA.

Higher percentage of CD3⁺CD154⁺ T lymphocytes predicts efficacy of TNF-α inhibitors in active axial SpA patients.

The objective of this study was to evaluate which subtypes of T lymphocytes (CD3(+)CD28(+) and CD3(+)CD154(+)) could predict clinical efficacy after TNF-α inhibitor treatment in active axial SpA patients. Patients who fulfilled Assessment of SpondyloArthritis international Society (ASAS) criteria for axial SpA had a BASDAI of ≥40 mm. All patients received TNF-α inhibitor treatment for 12 weeks. ASAS20 was used to evaluate the effect of the treatment at week 12. We detected the percentage of CD3(+)CD28(+) and CD3(+)CD154(+) T lymphocytes on lymphocyte cells in the peripheral blood in patients and healthy controls. We evaluated whether the percentage of the above subtypes of T lymphocytes could predict clinical efficacy by ROC curve analysis. Fifty-eight healthy controls and 74 active axial SpA patients were included. Mean age was 26.28 ± 9.08 and 26.95 ± 8.13 years for healthy controls and patients, respectively (p = 0.767). The percentage of CD3(+)CD154(+) T lymphocytes was significantly higher in axial SpA patients than in healthy controls (1.62 ± 1.89 % vs 0.79 ± 0.52 %, p < 0.0005). At baseline, the percentage of CD3(+)CD154(+) T lymphocytes was significantly higher in HLA-B27((+)) patients than HLA-B27((-)) ones (HLA-B27(+) vs HLA-B27(-):1.77 ± 1.95 % vs 0.41 ± 0.27 %, p = 0.005). Compared with baseline, the percentage of CD3(+)CD154(+) T lymphocytes significantly decreased to 0.87 ± 0.49 % at week 12 (p < 0.0005). Moreover, we found higher percentage of CD3(+)CD154(+) T lymphocytes could predict clinical efficacy of SpA patients with TNF-α inhibitor treatment (AUC = 0.733, p = 0.014). High percentage of CD3(+)CD154(+) is over-expressed on lymphocytes in peripheral blood of active SpA patients and can be down-regulated by TNF-α inhibitor therapy. High-percentage of CD3(+)CD154(+) T lymphocytes may predict clinical efficacy of TNF-α inhibitor treatment in active axial SpA patients.

ERAP1 is associated with ankylosing spondylitis in Han Chinese.

OBJECTIVE: Genetic components play important roles in the incidence and development of ankylosing spondylitis (AS). Aminopeptidase regulator of tumor necrosis factor receptor shedding 1 (ERAP1) was recently found to be associated with AS in North American and British cohorts. We evaluated whether ERAP1 is associated with AS in a Chinese Han population. METHODS: A sample of 50 patients and 50 healthy controls was recruited for preliminary screening for informative single-nucleotide polymorphisms (SNP). Then 6 SNP of suggestive significance in the initial screening were followed up in a large sample of 471 patients with AS and 456 ethnically matched controls. Diagnosis of AS followed the 1984 modified New York criteria. Linkage disequilibrium coefficient (D' and r(2)) and haplotypes were estimated by Haploview. Result. Two SNP (rs27434, p = 0.00039, and rs27529, p = 0.0083) in ERAP1 other than that reported previously were found to be significantly associated with AS. Haplotype analysis using 5 SNP within 1 linkage disequilibrium block identified 2 risk haplotypes (GATGT and GACGT) and 1 protective haplotype (GGTGT) for AS. CONCLUSION: Our study demonstrated that 2 novel SNP in ERAP1 were associated with AS in the Han Chinese population, suggesting that ERAP1 might confer genetic risk for AS in Han Chinese through the common mechanism shared by different populations, although the AS-associated SNP in ERAP1 might be population-specific.

Abnormal high-expression of CD154 on T lymphocytes of ankylosing spondylitis patients is down-regulated by etanercept treatment.

The pathogenesis of ankylosing spondylitis (AS) still remains an enigma. Although some studies have indicated the importance of T-cells and proinflammatory cytokines in the pathogenesis of the AS, it is still unknown whether co-stimulatory molecule CD154 participates in the pathogenesis of AS and how its level changes during the anti-TNF-alpha treatment of AS. This study is performed to evaluate the expression of CD154 in peripheral blood T-lymphocytes of patients with AS and observe the change of CD154 in etanercept-treated AS patient. We collected the peripheral blood and clinical data from 66 AS, 30 rheumatoid arthritis (RA) patients, and 30 healthy controls. Thirty-nine active AS patients were enrolled in a randomized double-blind placebo-controlled trial. We followed up 37 cases that fulfilled the ASAS20 response criteria after they finished etanercept treatment till week 48. The percentage of CD3+CD154+ in peripheral blood lymphocytes was evaluated by flow cytometry. We found that CD154 expression in AS patients was significantly higher than that in healthy volunteers and RA patients (both P < 0.001). The expressions of CD154 in AS patients at active stage or with peripheral joint involvement were significantly higher than those at stable stage or with axial involvement alone (P = 0.005 and 0.044, respectively). The expression of CD154 decreased in AS patients treated with etanercept compared with patients treated with placebo at week 6 (P < 0.001). Compared with healthy volunteers, the expression of CD154 in 16 AS patients who relapsed after finishing etanercept treatment was elevated again (P = 0.012). These findings show that co-stimulatory molecule CD154 is overexpressed on T-lymphocytes in peripheral blood of AS patients and can be down-regulated by etanercept treatment, which suggest that CD154 might be involved in the inflammatory evolvement of AS and might be a potential biomarker to monitor AS disease activity and the effect of etanercept treatment.

Value of the peripheral blood B-cells subsets in patients with ankylosing spondylitis.

BACKGROUND: The role of B-cell remains an enigma in the pathogenesis of ankylosing spondylitis (AS). This study aimed to investigate the distributions of B-cells and subsets in peripheral blood of AS patients and observe their changes in etanercept-treated AS patents. METHODS: We detected the proportions of CD19(+) B-cell, naive B-cell (CD19(+)CD27-), memory B-cell (CD19(+)CD27dim) and plasmablast (CD19(+)CD27high) in peripheral blood of 66 patients with AS (39 at active stage, 27 at stable stage; 35 patients with peripheral joint involvement, 31 patients with axial involvement alone), 30 patients with rheumatoid arthritis (RA) and 30 healthy volunteers using flow cytometry. And then we observed the changes of the above indexes of 39 active AS patients treated with etanercept in a randomized, double-blind, placebo-controlled trial. RESULTS: (1) Percentages of CD19(+) B-cells in active or peripheral joint involvement AS patients increased more obviously than those in stable or axial involvement alone AS patients (both P = 0.001), and percentage of CD19(+)CD27high B-cells in AS patients with peripheral joint involvement was significantly higher than that in cases with axial involvement alone or healthy volunteers (P = 0.005 and 0.006, respectively); (2) The percentage of CD19(+) B-cells in AS patients was positively correlated with Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores, Patient's Global Assessment (PGA) scores, total back pain scores and nocturnal back pain scores (r = 0.270, 0.255, 0.251 and 0.266, P = 0.029, 0.039, 0.042 and 0.031, respectively); (3) At week 6 and week 12, there were no statistical differences of the percentages of B-cells and subsets between etanercept group and placebo group of AS patients (P > 0.05); the percentage of CD19(+) B-cells in etanercept group was higher than that in healthy volunteers at week 12 (t = 3.320, P = 0.003). CONCLUSIONS: Misbalance is present in B-cells and some subsets in peripheral blood of active AS patients with peripheral joint involved. B-cells might play an important role in the pathogenesis of AS patients. The high percentage of CD19(+) B-cells in active AS patients cannot be down-regulated after 12-week etanercept treatment.