How Does Smoking Cessation Affect Disease Activity, Function Loss, and Quality of Life in Smokers With Ankylosing Spondylitis?

Risk Factors for Chronic Abdominal Pain After RYGB: Are Patients Adequately Selected Beforehand?

PURPOSE

Chronic abdominal pain after RYGB is a known issue. Identifying the potential patient-related and modifiable risk factors might contribute to diminish the risk for this undesirable outcome.

METHODS

A single-center retrospective cohort study with prospective data collection was conducted with inclusion of all patients who underwent RYGB surgery between 2015 and 2021. Data from the NBSR and medical records were used. Patients with chronic abdominal pain were defined when pain lasting or recurring for more than 3 to 6 months.

RESULTS

Six hundred sixty-four patients who underwent RYGB surgery were included with a median follow-up of 60.5 months. Forty-nine patients (7.3%) presented with chronic abdominal pain. Postoperative complications (OR 13.376, p = 0.020) and diagnosis of depression (OR 1.971, p = 0.037) were associated with developing abdominal pain. On the other hand, ex-smokers (OR 0.222, p = 0.040) and older age (0.959, p = 0.004) presented as protective factors.

CONCLUSION

Postoperative complications and diagnosis of depression are risk factors for chronic pain after RYGB. The role of the bariatric MDT remains crucial to select these patients adequately beforehand.

Cardiovascular Disease and Cardiac Imaging in Inflammatory Arthritis

Cardiovascular morbidity and mortality are more prevalent in inflammatory arthritis (IA) compared to the general population. Recognizing the importance of addressing this issue, the European League Against Rheumatism (EULAR) published guidelines on cardiovascular disease (CVD) risk management in IA in 2016, with plans to update going forward based on the latest emerging evidence. Herein we review the latest evidence on cardiovascular disease in IA, taking a focus on rheumatoid arthritis, psoriatic arthritis, and axial spondylarthritis, reflecting on the scale of the problem and imaging modalities to identify disease. Evidence demonstrates that both traditional CVD factors and inflammation contribute to the higher CVD burden. Whereas CVD has decreased with the newer anti-rheumatic treatments currently available, CVD continues to remain an important comorbidity in IA patients calling for prompt screening and management of CVD and related risk factors. Non-invasive cardiovascular imaging has been attracting much attention in view of the possibility of detecting cardiovascular lesions in IA accurately and promptly, even at the pre-clinical stage. We reflect on imaging modalities to screen for CVD in IA and on the important role of rheumatologists and cardiologists working closely together.

No Evidence of a Genetic Causal Relationship between Ankylosing Spondylitis and Gut Microbiota: A Two-Sample Mendelian Randomization Study

Objective: Ankylosing spondylitis (AS) is associated with a variety of gut microbiotas. We aim to analyze the causal relationship between the two at the genetic level. Methods: Mendelian randomization (MR) is a type of instrumental variables (IVs) analysis; MR follows the Mendelian genetic rule of "parental alleles are randomly assigned to offspring" and takes genetic variation as IVs to infer the causal association between exposure factors and study outcome in observational studies. Genome-wide association study (GWAS) summary data of AS were from the FinnGen consortium, and the gut microbiota (Bacteroides, Streptococcus, Proteobacteria, Lachnospiraceae) were from the MiBioGen consortium. The TwoSampleMR and MRPRESSO packages of the R were used to perform a two-sample MR study. Random-effects inverse variance weighted (IVW) was the main analysis method, and MR Egger, weighted median, simple mode, and weighted mode were used as supplementary methods. We examined heterogeneity and horizontal pleiotropy, and examined whether the analysis results were influenced by a single SNP. We applied radial variants of the IVW and MR-Egger model for the improved visualization of the causal estimate. We further examined the causal relationship between AS and gut microbiota, and the robustness of the analysis results. Finally, we performed maximum likelihood, penalized weighted median, and IVW (fixed effects) to further identify the potential causal association. Results: The random-effects IVW results showed that Bacteroides (p = 0.965, OR 95% confidence interval [CI] = 0.990 [0.621-1.579]), Streptococcus (p = 0.591, OR 95% CI = 1.120 [0.741-1.692]), Proteobacteria (p = 0.522, OR 95% CI = 1.160 [0.737-1.826]), and Lachnospiraceae (p = 0.717, OR 95% CI = 1.073 [0.732-1.574]) have no genetic causal relationship with AS. There was no heterogeneity, horizontal pleiotropy or outliers, and results were normally distributed. The MR analysis results were not driven by a single SNP. Conclusions: This study showed that Bacteroides, Streptococcus, Proteobacteria and Lachnospiraceae, four common gut microbiotas associated with AS, had no causal relationship with AS at the genetic level. This study makes a positive contribution to the genetics of AS, but the insufficient number of gut microbiota included is a limitation.

No evidence of a genetic causal relationship between ankylosing spondylitis and iron homeostasis: A two-sample Mendelian randomization study

Background

Ankylosing spondylitis (AS) is an immune-mediated chronic inflammatory disease that leads to bone hyperplasia and spinal ankylosis. Iron homeostasis plays a very important role in the inflammatory response and is closely related to the pathogenesis of AS. This study aimed to use large-scale genome-wide association study (GWAS) summary data to study the genetic causal relationship between AS and iron homeostasis using Mendelian randomization (MR).

Methods

Genome-wide association study summary data of AS and iron homeostasis-related indicators were obtained from the FinnGen consortium and the DeCODE genetics database, respectively. We used four iron homeostasis-related indicators: ferritin, serum iron, total iron binding capacity (TIBC), and transferrin saturation (TSAT) for two-sample MR analyses to test for genetic causal association with AS using the "TwoSampleMR" package of the R software (version 4.1.2). The random-effects inverse variance weighted (IVW) method was the main analysis method used for MR. We examined the MR analysis results for heterogeneity, horizontal pleiotropy, and possible outliers. In addition, we confirmed the robustness of the MR analysis by testing whether the results were affected by a single SNP and whether they followed a normal distribution.

Results

The random-effects IVW results showed that ferritin [p = 0.225, OR 95% confidence interval (CI) = 0.836 (0.627-1.116)], serum iron [p = 0.714, OR 95% CI = 0.948 (0.714-1.260)], TIBC [p = 0.380, OR 95% CI = 0.917 (0.755-1.113)], and TSAT [p = 0.674, OR 95% CI = 0.942 (0.713-1.244)] have no genetic causal relationship with AS. We detected no heterogeneity，horizontal pleiotropy and possible outliers in our MR analysis (p > 0.05). In addition, our MR analysis results were not affected by a single SNP, and were normally distributed.

Conclusion

Our study did not detect a genetic causal relationship between AS and iron homeostasis. Nonetheless, this does not rule out a relationship between the two at other mechanistic levels.

Consensus statement on smoking cessation in patients with pain

Smoking is closely associated with the development of various cancers and tobacco-related illnesses such as cardiovascular and respiratory disorders. However, data are scarce on the relationship between smoking and both acute and chronic pain. In addition to nicotine, tobacco smoke contains more than 4000 different compounds. Although nicotine is not the sole cause of smoking-induced diseases, it plays a critical role in pain-related pathophysiology. Despite the acute analgesic effects of nicotine, long-term exposure leads to tolerance and increased pain sensitivity due to nicotinic acetylcholine receptor desensitization and neuronal plastic changes. The purpose of smoking cessation interventions in smoking patients with pain is primarily not only to reduce their pain and associated limitations in activities of daily living, but also to improve the outcomes of underlying pain-causing conditions and reduce the risks of tobacco-related disorders. This statement aims to summarize the available evidence on the impact of smoking on pain and to inform medical professionals of the significance of smoking cessation in patients with pain.

Lifestyle modification and inflammation in people with axial spondyloarthropathy-A scoping review

INTRODUCTION

People with axial spondyloarthritis (AS) have an inflammatory profile, increasing the risk of hypertension, type 2 diabetes, obesity, and dyslipidaemia. Consequently, AS is linked with co-morbidities such as cardiovascular disease (CVD). Physical inactivity, diet, smoking, alcohol consumption, and obesity influence inflammation, but knowledge of the interaction between these with inflammation, disease activity, and CVD risk in AS is dominated by cross-sectional research.

METHODS

A review of the literature was conducted between July 2020 and December 2021. The focus of the scoping review is to summarise longitudinal and randomised control trials in humans to investigate how tracking or modifying lifestyle influences inflammation and disease burden in patients with AS. KEY MESSAGES: (1) Lifestyle modifications, especially increased physical activity (PA), exercise, and smoking cessation, are critical in managing AS. (2) Smoking is negatively associated with patient reported outcome measures with AS, plus pharmaceutical treatment adherence, but links with structural radiographic progression are inconclusive. (3) Paucity of data warrant structured studies measuring inflammatory cytokine responses to lifestyle modification in AS.

CONCLUSION

Increased PA, exercise, and smoking cessation should be supported at every given opportunity to improve health outcomes in patients with AS. The link between smoking and radiographic progression needs further investigation. Studies investigating the longitudinal effect of body weight, alcohol, and psychosocial factors on disease activity and physical function in patients with AS are needed. Given the link between inflammation and AS, future studies should also incorporate markers of chronic inflammation beyond the standard C-reactive protein and erythrocyte sedimentation rate measurements.

Vitamin D and risk of ankylosing spondylitis: A two-sample mendelian randomization study

OBJECTIVES

To study whether Vitamin D levels are causally associated with ankylosing spondylitis (AS).

METHODS

Two-sample Mendelian randomization (TSMR) analysis was performed by employing MR-Egger regression, weighted median (WM¹), inverse-variance weighted (IVW), and weight mode (WM²) methods. The odds ratio (OR) with 95% confidence intervals (CIs) was used to evaluate this association.

RESULTS

The results of IVW show that no causal association between vitamin D and AS (OR = 0.999, 95%CI = 0.997, 1.002, P = 0.724). The MR-Egger regression results show that genetic pleiotropy does not bias the results (intercept = -4.474E-05, SE = 2.830E-05, P = 0.255). The MR-Egger method no supported causal association between vitamin D and AS (OR = 1.000, 95%CI = 0.996, 1.005, P = 0.879). WM¹ (OR = 1.002, 95%CI = 0.999, 1.005, P = 0.837) and WM² (OR = 0.998, 95%CI = 0.996, 1.002, P = 0.910) approach also not found a causal relationship between vitamin D levels and AS. The significant heterogeneity was not observed by Cochran's Q test. The "leave-one-out" analysis also proved lack of a single SNP affected the robustness of our results.

CONCLUSION

Based on our analysis, there is lack of a strong evidence to support a causal inverse association between vitamin D levels and ankylosing spondylitis.

Relationship between smoking, clinical, inflammatory, and radiographic parameters in patients with ankylosing spondylitis

Background

Ankylosing spondylitis (AS) is an autoimmune multisystemic disease that attacks the spine, sacroiliacs, and often causes asymmetrical peripheral oligoarthritis. It results from the interaction between the genetic factors mainly Human Leukocyte Antigen B27 (HLA B27) and environmental factors. Current smoking has been reported to be a major risk factor for the incidence and progression of ankylosing spondylitis. So, we aim to explore the relationship between smoking and each of the clinical, inflammatory markers, functional limitation, and radiographic progression in ankylosing spondylitis patients.

Results

Fifty ankylosing spondylitis patients were included in this study. Comparisons of clinical data, radiographic, and inflammatory markers among smokers and nonsmokers revealed that AS current smokers showed a statistically significant decrease in chest expansion, increase in the occiput to wall distance (p < 0.001**), higher inflammatory marker, higher disease activity indices (Ankylosing Spondylitis Disease Activity Score, Bath Ankylosing Spondylitis Disease Activity Index), higher Bath Ankylosing Spondylitis functional index, and modified Stoke Ankylosing Spondylitis Spine Score than nonsmokers (P < 0.001**). The smoking index was positively correlated with BASFI, ASDAS, (mSASSS) (r = 0.584, p = 0.005*) and negatively correlated with chest expansion.

Conclusions

Current smoking in ankylosing spondylitis patients is associated with higher disease activity, inflammatory markers, functional disability, and radiological progression. This may add to the disease burden and thus interferes with the personal daily activities, physical mobility, life quality, and the response to TNFi therapy. So, stopping smoking is a mandatory step in controlling the disease activity and having favorable outcome.

Smoking cessation for improving mental health

BACKGROUND

There is a common perception that smoking generally helps people to manage stress, and may be a form of 'self-medication' in people with mental health conditions. However, there are biologically plausible reasons why smoking may worsen mental health through neuroadaptations arising from chronic smoking, leading to frequent nicotine withdrawal symptoms (e.g. anxiety, depression, irritability), in which case smoking cessation may help to improve rather than worsen mental health.

OBJECTIVES

To examine the association between tobacco smoking cessation and change in mental health.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group's Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, Embase, PsycINFO, and the trial registries clinicaltrials.gov and the International Clinical Trials Registry Platform, from 14 April 2012 to 07 January 2020. These were updated searches of a previously-conducted non-Cochrane review where searches were conducted from database inception to 13 April 2012.  SELECTION CRITERIA: We included controlled before-after studies, including randomised controlled trials (RCTs) analysed by smoking status at follow-up, and longitudinal cohort studies. In order to be eligible for inclusion studies had to recruit adults who smoked tobacco, and assess whether they quit or continued smoking during the study. They also had to measure a mental health outcome at baseline and at least six weeks later.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods for screening and data extraction. Our primary outcomes were change in depression symptoms, anxiety symptoms or mixed anxiety and depression symptoms between baseline and follow-up. Secondary outcomes  included change in symptoms of stress, psychological quality of life, positive affect, and social impact or social quality of life, as well as new incidence of depression, anxiety, or mixed anxiety and depression disorders. We assessed the risk of bias for the primary outcomes using a modified ROBINS-I tool.  For change in mental health outcomes, we calculated the pooled standardised mean difference (SMD) and 95% confidence interval (95% CI) for the difference in change in mental health from baseline to follow-up between those who had quit smoking and those who had continued to smoke. For the incidence of psychological disorders, we calculated odds ratios (ORs) and 95% CIs. For all meta-analyses we used a generic inverse variance random-effects model and quantified statistical heterogeneity using I2. We conducted subgroup analyses to investigate any differences in associations between sub-populations, i.e. unselected people with mental illness, people with physical chronic diseases. We assessed the certainty of evidence for our primary outcomes (depression, anxiety, and mixed depression and anxiety) and our secondary social impact outcome using the eight GRADE considerations relevant to non-randomised studies (risk of bias, inconsistency, imprecision, indirectness, publication bias, magnitude of the effect, the influence of all plausible residual confounding, the presence of a dose-response gradient).

MAIN RESULTS

We included 102 studies representing over 169,500 participants. Sixty-two of these were identified in the updated search for this review and 40 were included in the original version of the review.  Sixty-three studies provided data on change in mental health, 10 were included in meta-analyses of incidence of mental health disorders, and 31 were synthesised narratively.  For all primary outcomes, smoking cessation was associated with an improvement in mental health symptoms compared with continuing to smoke: anxiety symptoms (SMD -0.28, 95% CI -0.43 to -0.13; 15 studies, 3141 participants; I2 = 69%; low-certainty evidence); depression symptoms: (SMD -0.30, 95% CI -0.39 to -0.21; 34 studies, 7156 participants; I2 = 69%' very low-certainty evidence);  mixed anxiety and depression symptoms (SMD -0.31, 95% CI -0.40 to -0.22; 8 studies, 2829 participants; I2 = 0%; moderate certainty evidence).  These findings were robust to preplanned sensitivity analyses, and subgroup analysis generally did not produce evidence of differences in the effect size among subpopulations or based on methodological characteristics. All studies were deemed to be at serious risk of bias due to possible time-varying confounding, and three studies measuring depression symptoms were judged to be at critical risk of bias overall. There was also some evidence of funnel plot asymmetry. For these reasons, we rated our certainty in the estimates for anxiety as low, for depression as very low, and for mixed anxiety and depression as moderate. For the secondary outcomes, smoking cessation was associated with an improvement in symptoms of stress (SMD -0.19, 95% CI -0.34 to -0.04; 4 studies, 1792 participants; I2 = 50%), positive affect (SMD 0.22, 95% CI 0.11 to 0.33; 13 studies, 4880 participants; I2 = 75%), and psychological quality of life (SMD 0.11, 95% CI 0.06 to 0.16; 19 studies, 18,034 participants; I2 = 42%). There was also evidence that smoking cessation was not associated with a reduction in social quality of life, with the confidence interval incorporating the possibility of a small improvement (SMD 0.03, 95% CI 0.00 to 0.06; 9 studies, 14,673 participants; I2 = 0%). The incidence of new mixed anxiety and depression was lower in people who stopped smoking compared with those who continued (OR 0.76, 95% CI 0.66 to 0.86; 3 studies, 8685 participants; I2 = 57%), as was the incidence of anxiety disorder (OR 0.61, 95% CI 0.34 to 1.12; 2 studies, 2293 participants; I2 = 46%). We deemed it inappropriate to present a pooled estimate for the incidence of new cases of clinical depression, as there was high statistical heterogeneity (I2 = 87%).

AUTHORS' CONCLUSIONS

Taken together, these data provide evidence that mental health does not worsen as a result of quitting smoking, and very low- to moderate-certainty evidence that smoking cessation is associated with small to moderate improvements in mental health.  These improvements are seen in both unselected samples and in subpopulations, including people diagnosed with mental health conditions. Additional studies that use more advanced methods to overcome time-varying confounding would strengthen the evidence in this area.

Smoking in spondyloarthritis: unravelling the complexities

Tobacco smoking is a major threat to health. There is no doubt about the need to promote and support cessation at every opportunity. Smoking has a clear role in RA, but what evidence is there that the same relationship exists in SpA? In this review, we examine (the less cited) paradoxes and contradictions in the existing axial SpA (axSpA) and PsA literature; for example, smoking appears to be 'protective' for some axSpA manifestations. We also highlight findings from higher quality evidence: smoking is associated with increased risk of PsA and the risk of psoriasis in axSpA. The relationship between smoking and SpA is far from simple. Our aim is to highlight the harms of smoking in SpA and bring attention to inconsistencies in the literature to inform further research.

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.

Smoking cessation intervention for reducing disease activity in chronic autoimmune inflammatory joint diseases

BACKGROUND

Chronic inflammatory joint diseases (IJDs) affect 1% to 2% of the population in developed countries. IJDs include rheumatoid arthritis (RA), ankylosing spondylitis (AS), psoriatic arthritis (PsA), and other forms of spondyloarthritis (SpA). Tobacco smoking is considered a significant environmental risk factor for developing IJDs. There are indications that smoking exacerbates the symptoms and worsens disease outcomes.

OBJECTIVES

The objective of this review was to investigate the evidence for effects of smoking cessation interventions on smoking cessation and disease activity in smokers with IJD.

SEARCH METHODS

We searched the Cochrane Tobacco Addiction Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Library; PubMed/MEDLINE; Embase; PsycINFO; the Cumulative Index to Nursing and Allied Health Literature (CINAHL); and three trials registers to October 2018.

SELECTION CRITERIA

We included randomised controlled trials testing any form of smoking cessation intervention for adult daily smokers with a diagnosis of IJD, and measuring smoking cessation at least six months after baseline.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane.

MAIN RESULTS

We included two studies with 57 smokers with a diagnosis of rheumatoid arthritis (RA). We identified no studies including other IJDs. One pilot study compared a smoking cessation intervention specifically for people with RA with a less intensive, generic smoking cessation intervention. People included in the study had a mean age of 56.5 years and a disease duration of 7.7 years (mean). The second study tested effects of an eight-week cognitive-behavioural patient education intervention on cardiovascular disease (CVD) risk for people with RA and compared this with information on CVD risk only. The intervention encouraged participants to address multiple behaviours impacting CVD risk, including smoking cessation, but did not target smoking cessation alone. People included in the study had a mean age of 62.2 years (intervention group) and 60.8 years (control group), and disease duration of 11.6 years (intervention group) and 14.1 years (control group). It was not appropriate to perform a meta-analysis of abstinence data from the two studies due to clinical heterogeneity between interventions. Neither of the studies individually provided evidence to show benefit of the interventions tested. Only one study reported on adverse effects. These effects were non-serious, and numbers were comparable between trial arms. Neither of the studies assessed or reported disease activity or any of the predefined secondary outcomes. We assessed the overall certainty of evidence as very low due to indirectness, imprecision, and high risk of detection bias based on GRADE.

AUTHORS' CONCLUSIONS

We found very little research investigating the efficacy of smoking cessation intervention specifically in people with IJD. Included studies are limited by imprecision, risk of bias, and indirectness. Neither of the included studies investigated whether smoking cessation intervention reduced disease activity among people with IJD. High-quality, adequately powered studies are warranted. In particular, researchers should ensure that they measure disease markers and quality of life, in addition to long-term smoking cessation.

Ankylosing spondylitis: etiology, pathogenesis, and treatments

Ankylosing spondylitis (AS), a common type of spondyloarthropathy, is a chronic inflammatory autoimmune disease that mainly affects spine joints, causing severe, chronic pain; additionally, in more advanced cases, it can cause spine fusion. Significant progress in its pathophysiology and treatment has been achieved in the last decade. Immune cells and innate cytokines have been suggested to be crucial in the pathogenesis of AS, especially human leukocyte antigen (HLA)‑B27 and the interleukin‑23/17 axis. However, the pathogenesis of AS remains unclear. The current study reviewed the etiology and pathogenesis of AS, including genome-wide association studies and cytokine pathways. This study also summarized the current pharmaceutical and surgical treatment with a discussion of future potential therapies.

Metal-triggered conformational reorientation of a self-peptide bound to a disease-associated HLA-B*27 subtype

Conformational changes of major histocompatibility complex (MHC) antigens have the potential to be recognized by T cells and may arise from polymorphic variation of the MHC molecule, the binding of modifying ligands, or both. Here, we investigated whether metal ions could affect allele-dependent structural variation of the two minimally distinct human leukocyte antigen (HLA)-B*27:05 and HLA-B*27:09 subtypes, which exhibit differential association with the rheumatic disease ankylosing spondylitis (AS). We employed NMR spectroscopy and X-ray crystallography coupled with ensemble refinement to study the AS-associated HLA-B*27:05 subtype and the AS-nonassociated HLA-B* 27:09 in complex with the self-peptide pVIPR (RRKWRRWHL). Both techniques revealed that pVIPR exhibits a higher degree of flexibility when complexed with HLA-B*27:05 than with HLA-B*27:09. Furthermore, we found that the binding of the metal ion Cu²⁺ or Ni²⁺, but not Mn²⁺, Zn²⁺, or Hg²⁺, affects the structure of a pVIPR-bound HLA-B*27 molecule in a subtype-dependent manner. In HLA-B*27:05, the metals triggered conformational reorientations of pVIPR, but no such structural changes were observed in the HLA-B*27:09 subtype, with or without bound metal ion. These observations provide the first demonstration that not only major histocompatibility complex class II, but also class I, molecules can undergo metal ion-induced conformational alterations. Our findings suggest that metals may have a role in triggering rheumatic diseases such as AS and also have implications for the molecular basis of metal-induced hypersensitivities and allergies.