Collagen-specific cytotoxic T lymphocyte responses in patients with ankylosing spondylitis and reactive arthritis

Both ankylosing spondylitis (AS) and reactive arthritis (ReA) are strongly associated with HLA-B27 although the mechanism for this association is still unknown. Here we examine the hypothesis that B27-restricted, joint antigen-specific cytotoxic T lymphocytes (CTL) may be the driving force of AS and ReA. Type II and type XI procollagens (CII and CXI, respectively), expressed almost exclusively in the articular cartilage of the joints, were chosen as the possible targets of autoimmune CTL. Type I procollagen (CI), expressed in many different tissues, was also included as control. Nineteen nonamer peptides bearing appropriate HLA-B27 binding motifs from human CI, CII and CXI were identified and synthesized. When analyzed for binding affinity to HLA-B27 in assembly assays, four (two from CII, two from CXI) were found capable of binding to HLA-B27 with high affinity. These B27-binding collagen peptides were then used to stimulate peripheral blood lymphocytes from eight B27-positive AS and three ReA patients for identification of possible B27-restricted autoimmune CTL. HLA-B27-restricted CTL specific for one of the CII peptides, P109 were found in one of the ReA patients, but in none of the others.     

Blood lymphocytes from ankylosing spondylitis patients fail to induce disease-specific cytotoxic T lymphocytes

The intriguing observation made by Geczy et al. (1) showing the possibility of generating specific ankylosing spondylitis--cytotoxic T lymphocytes by presenting HLA-B27+AS+ cells as antigen-specific stimulator cells prompted us (by using Geczy's approach) to identify cytotoxic T lymphocytes specific for this apparent B27+AS+ target structure. Peripheral blood mononuclear cells (PBMC) of 21 healthy B27+ individuals were stimulated in primary and in short-term cultures with PBMC of an HLA-identical sibling suffering from definite AS (n = 12). In addition, PBMC in vitro modified by "Geczy bacterial products" from two healthy B27+ individuals were used to stimulate B27+ AS- lymphocytes (either autologous or from a healthy HLA-identical sibling). Effector cells raised in primary AS- versus AS+ and AS- versus "modified B27" mixed lymphocyte culture combinations showed no proliferative nor cytotoxic activity at all. The scarcely observed cytotoxic reactivity of restimulated mixed lymphocyte culture was not restricted to AS+B27+ cells. These results demonstrate that PBMC from ankylosing spondylitis patients fail to induce disease-specific cytotoxic T lymphocytes and suggest that an ankylosing spondylitis--related "modified B27" structure does not exist, at least in the patient material tested.     

Genetics of ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory arthritis that affects the spine and sacroiliac joints. It causes significant disability and is associated with a number of other features including peripheral arthritis, anterior uveitis, psoriasis and inflammatory bowel disease (IBD). Significant progress has been made in the genetics of AS have in the last five years, leading to new treatments in trial, and major leaps in understanding of the aetiopathogenesis of the disease.     

Achondroplasia with ankylosing spondylitis

A 41-year-old-white man with achondroplasia has been followed intermittently since age 27. During this time, he has complained of neck and back pain with limited mobility in both. Other problems have included temporomandibular joint pain, dysuria without apparent urinary tract infection iritis, anemia, and an elevated gamma globulin fraction. Recently he returned to the clinic complaining of rigidity of the entire spine. Radiographs showed complete fusion of the sacroiliac joints and fusion of the cervical vertebral bodies and apophyseal joints, consistent with ankylosing spondylitis. He was found to be HLA B-27 positive. This case illustrates the importance of considering other diseases whenever atypical orthopedic problems arise in patients with a bone dysplasia.     

Genetics and genomics of ankylosing spondylitis

Summary: Ankylosing spondylitis (AS) is a common, highly heritable arthropathy, the pathogenesis of which is poorly understood. The mechanism by which the main gene for the disease, HLA-B27, leads to AS is unknown. Genetic and genomic studies have demonstrated involvement of the interleukin-23 (IL-23) signaling pathway in AS, a finding which has stimulated much new research into the disease and has led to therapeutic trials. Several other genes and genetic regions, including further major histocompatibility complex (MHC) and non-MHC loci, have been shown to be involved in the disease, but it is not clear yet how they actually induce the condition. These findings have shown that there is a strong genetic overlap between AS and Crohn’s disease in particular, although there are also major differences in the genes involved in the two conditions, presumably explaining their different presentations. Genomic and proteomic studies are in an early phase but have potential both as diagnostic/prognostic tools and as a further hypothesis-free tool to investigate AS pathogenesis. Given the slow progress in studying the mechanism of association of HLA-B27 with AS, these may prove to be more fruitful approaches to investigating the pathogenesis of the disease.     

HLA-B27 misfolding and ankylosing spondylitis

Understanding how HLA-B27 contributes to the pathogenesis of spondyloarthritis continues to be an important goal. Current efforts are aimed largely on three areas of investigation; peptide presentation to CD8T cells, abnormal forms of the HLA-B27 heavy chain and their recognition by leukocyte immunoglobulin-like receptors on immune effector cells, and HLA-B27 heavy chain misfolding and intrinsic biological effects on affected cells. In this chapter we review our current understanding of the causes and consequences of HLA-B27 misfolding, which can be defined biochemically as a propensity to oligomerize and form complexes in the endoplasmic reticulum (ER) with the chaperone BiP (HSPA5/GRP78). HLA-B27 misfolding is linked to an unusual combination of polymorphisms that identify this allele, and cause the heavy chain to fold and load peptides inefficiently. Misfolding can result in ER-associated degradation (ERAD) of heavy chains, which is mediated in part by the E3 ubiquitin ligase HRD1 (SYVN1), and the ubiquitin conjugating enzyme UBE2JL. Upregulation of HLA-B27 and accumulation of misfolded heavy chains can activate ER stress signaling pathways that orchestrate the unfolded protein response. In transgenic rats where HLA-B27 is overexpressed, UPR activation is prominent. However, it is specific for heavy chain misfolding, since overexpression of HLA-B7, an allele that does not misfold, fails to generate ER stress. UPR activation has been linked to cytokine dysregulation, promoting lL-23, IFNβ, and lL-1α production, and may activate the IL-23/IL-17 axis in these rats. IL-1α and IFNβ are pro- and anti-osteoclastogenic cytokines, respectively, that modulate osteoclast development in HLA-B27-expressing transgenic rat monocytes. Translational studies of patient derived cells expressing HLA-B27 at physiologic levels have provided evidence that ER stress and UPR activation can occur in peripheral blood, but this has not been reported to date in isolated macrophages. Inflamed gastrointestinal tissue reveals evidence for HLA-B27 misfolding, ERAD, and autophagy, without acute UPR activation. A more complete picture of conditions that impact HLA-B27 folding and misfolding, the full spectrum and time course of consequences of ER stress, and critical cell types involved is needed to understand the role of HLA-B27 misfolding in spondyloarthritis pathogenesis.     

The treatment of ankylosing spondylitis

Ankylosing spondylitis is an inflammatory disorder affecting the axial skeleton and periphery. Symptoms can often be debilitating. Current therapy for the disease include physical therapy, non-steroidal anti-inflammatory drugs (NSAIDS, anti-rheumatic disease modifying drugs (DMARDS), and the newly developed biologic agents targeting tumor necrosis factor alpha (TNF-α). This paper will provide a comprehensive review of these treatments which focusing on evidence based medicine for the daily clinical practice of rheumatology. Received: 31 December 2002 / Accepted: 15 January 2003 Correspondence to J.C. Davis Jr.     

Etanercept: in ankylosing spondylitis

Etanercept is a dimeric fusion protein based on the p75 tumor necrosis factor (TNF) receptor. It binds to TNFalpha and blocks its biological activity. Subcutaneous etanercept is effective in the treatment of rheumatoid arthritis, psoriatic arthritis, and polyarticular-course juvenile rheumatoid arthritis. More recently, etanercept has shown efficacy in the treatment of adults with ankylosing spondylitis. In randomized, double-blind, placebo-controlled trials, subcutaneous etanercept 25mg twice weekly for 6-24 weeks significantly reduced disease activity in patients with active ankylosing spondylitis. In the largest trial, etanercept produced a response rate of 57% compared with 22% for placebo after 24 weeks (response was determined via the validated ASAS 20 response criteria developed by the Assessments in Ankylosing Spondylitis [ASAS] Working Group). Etanercept therapy significantly improved health-related quality of life in patients with ankylosing spondylitis compared with placebo. The greatest improvements in a 16-week study were seen in the domains of physical functioning, physical role, bodily pain, vitality, and social functioning. Etanercept was generally well tolerated, with few serious adverse events or treatment withdrawals. The most common adverse events were injection-site reactions and minor upper respiratory tract infections.     

Impaired gait in ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic, inflammatory rheumatic disease. The spine becomes rigid from the occiput to the sacrum, leading to a stooped position. This study aims at evaluating AS subjects gait alterations. Twenty-four subjects were evaluated: 12 normal and 12 pathologic in stabilized anti-TNF-alpha treatment (mean age 49.42 (10.47), 25.44 (3.19) and mean body mass index 55.75 (3.19), 23.73 (2.7), respectively). Physical examination and gait analysis were performed. A motion capture system synchronized with two force plates was used. Three-dimensional kinematics and kinetics of trunk, pelvis, hip, knee and ankle were determined during gait. A trend towards reduction was found in gait velocity and stride length. Gait analysis results showed statistically significant alterations in the sagittal plane at each joint for AS patients (P < 0.049). Hip and knee joint extension moments showed a statistically significant reduction (P < 0.044). At the ankle joint, a decreased plantarflexion was assessed (P < 0.048) together with the absence of the heel rocker. Gait analysis, through gait alterations identification, allowed planning-specific rehabilitation intervention aimed to prevent patients’ stiffness together with improve balance and avoid muscles’ fatigue.     

Treat ankylosing spondylitis with methazolamide

Background: Increased bone resorption and new bone information are two characteristics of ankylosing spondylitis (AS). Much evidence has shown that carbonic anhydrase inhibitors can restrain bone resorption. We had detected increased expression of carbonic anhydrase I (CA1) in synovium of patients with AS. This study aimed to evaluate the effectiveness and safety of methazolamide, an anti-carbonic anhydrase drug, for treating patients with AS.Methods: Two patients, called as S and L, were diagnosed with active AS based on BASDAI and BASFI assessments, radiographic data and other clinical indices. They took methazolamide tablets at a dose of 25 mg twice every day.Results: Patient S''s BASDAI score fell from 5.4 to 4.4, while patient L''s BASDAI fell from 2.4 to 2. Patient S''s BASFI score change from 2.7 to 2.9, while patient L''s BASFI score fell from 1.2 to 0.2. The ESR values of patient S were considerably reduced, while the ESR value of patient L remained unchanged and in the normal range. The calcium concentration of patient S decreased from 3.05 mmol/L to 2.39 mmol/L. The CT evidence indicates that the articular surfaces of the erosive sacroiliac joints became clearer and the area of the calcium deposits began decreased. No significant systemic side effects were observed in either patient.Conclusions: The above results indicate that methazolamide was effective for active AS. Methazolamide may improve AS symptoms by inhibiting carbonic anhydrase activity during the processes of bone reporption and new bone formation.     

Juvenile ankylosing spondylitis with uveitis

A 17-year-old boy had suffered from right ankle arthralgia when he was 13 years old. He also had bilaterally congested conjunctivas and were erythematous around his right ankle joint. A soft tissue echo showed swelling of the right ankle joint. A Ga 67 scan revealed a focal elevated uptake in the right ankle, but a bone scan was negative. Reactive arthritis was suspected due to conjunctivitis, arthritis and a previous episode of watery diarrhea. An ophthalmologic examination showed no evidence of uveitis. Laboratory data were negative for rheumatoid factor, antinuclear antibody and anti-ds DNA. Erythrocyte sedimentation rate (ESR) was 40 mm/hr and a histocompatibility test was positive for antigen B27. Based on the diagnosis of cellulitis and reactive arthritis, oxacillin and naproxen were given for 14 days. During follow-up at the OPD, bilateral arthralgia of the ankle joints was noted and a sonography showed bilateral edematous ankle joints. Juvenile ankylosing spondylitis (JAS) was suspected. Two years later, he had lower back pain and arthralgia of the knee joints with uveitis of the right eye. He was treated with naproxen and prednisolone. Because few JAS cases initially present as axial arthropathy or enthesopathy and uveitis is uncommon in children, we presented the case with a review of literature and conclusion that the possibility of JAS should be considered in young adolescent boys with arthritis of the lower limbs, enthesitis, a family history of related diseases and positive HLA-B27, as well as negative rheumatoid factor (RF) and anti-nuclear antibody (ANA) results.     

Interleukin 10 polymorphisms in ankylosing spondylitis

Genetic polymorphisms of the IL10 promoter region have been implicated in many autoimmune diseases, including seronegative spondyloarthropathies. We studied three SNPs (IL10-1087, -824, and -597) and two microsatellites (IL10R and IL10G) lying within the promoter region of IL10 for association with susceptibility to and clinical manifestations of ankylosing spondylitis (AS), a common form of spondyloarthritis. Four hundred and sixty-eight individuals from 182 Finnish families affected with AS were studied. No association between individual IL10 promoter region polymorphisms or marker haplotype was observed with susceptibility to AS, but weak association was noted between the IL10-597 and -824 SNPs and age of disease onset (P=0.01 for each SNP). The IL10.G4 allele was associated with BASFI (corrected for disease duration) (P=0.03). We conclude that IL10 promoter polymorphisms have no significant effect on susceptibility to AS, but may play a minor role in determining age of disease onset and disease severity.     

强直性脊柱炎遗传学研究进展

强直性脊柱炎是一种具有高度遗传倾向的血清阴性脊柱关节病。既往的研究主要报道HLA-B27基因与AS的强相关性,但近年来大量的研究提示除HLA-B27基因外,可能还存在其他的MHC类和非MHC类基因与AS相关。本文综述了强直性脊柱炎的遗传学因素的研究进展,为其诊断、预防和治疗提供新的思路。     

ERAP1 structure,function and pathogenetic role in ankylosing spondylitis and other MHC-associated diseases

The endoplasmic reticulum aminopeptidase 1 (ERAP1) is a multifunctional enzyme involved in the final processing of Major Histocompatibility Complex class I (MHC-I) ligands and with a significant influence in the stability and immunological properties of MHC-I proteins. ERAP1 polymorphism is associated with ankylosing spondylitis among HLA-B27-positive individuals and the altered enzymatic activity of natural variants has significant effects on the HLA-B27 peptidome, suggesting a critical pathogenetic role of peptides in this disease. Likewise, the association of ERAP1 with other MHC-I associated disorders and its epistasis with their susceptibility MHC alleles point out to a general role of the MHC-I peptidome in these diseases. The functional interaction between ERAP1 and HLA-B27 or other MHC-I molecules may be related to the processing of specific epitopes, or to a more general peptide-dependent influence on other biological features of the MHC-I proteins. In addition, from a consideration of the reported functions of ERAP1, including its involvement in angiogenesis and macrophage activation, a more complex and multi-level influence in the inflammatory and immune pathways operating in these diseases cannot be ruled out.     

Old and new HLA associations with ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease that primarily involves the axial skeleton and the sacroiliac joint, but may also affect peripheral joints and entheses. AS susceptibility is clearly attributable to genetic factors and the link between human leukocyte antigen (HLA)-B27 and AS is the strongest association between an HLA class I molecule and a disease. However, there is evidence for the involvement of other, non-B27 factors within the major histocompatibility complex (MHC) in AS susceptibility. MHC class I is clearly the most significant genetic region for the disease, although most of the genetic association of this region is driven by HLA-B27. Moreover, several studies have investigated the MHC class II region and its association with AS. This review summarizes the current findings concerning the MHC genetics of the disease, focusing in particular on the associations of HLA with AS found in different ethnic populations throughout the world, and the possible mechanisms underlying them.     

The classification and diagnostic criteria of ankylosing spondylitis

Ankylosing spondylitis is the prototype of immune-mediated inflammatory rheumatic diseases grouped under the term spondyloarthritis (SpA). An early diagnosis has now become increasingly important because effective therapies are available and anti-TNF drugs are even more effective if used in early stages of the disease. In ankylosing spondylitis, the 1984 modified New York criteria have been used widely in clinical studies and daily practice but are not applicable in early disease when the characteristic radiographic signs of sacroiliitis are not visible but active sacroiliitis is readily detectable by magnetic resonance imaging (MRI). Thus there has been a need for new classification or diagnostic criteria to identify inflammatory spondyloarthritis at early stage of the disease. This led to the concept of axial SpA to include the entire spectrum of patients with axial disease both, with and without radiographic damage. New classification criteria for the wider group of SpA have been proposed by ASAS (Assessment of Spondylo Arthritis International Society); and the patients are sub-grouped into (1) a predominantly axial disease, termed axial SpA including AS and non-radiographic axial SpA; (2) peripheral SpA. The clinical course and disease process of non-radiographic axial spondyloarthritis remains unclear. However the development of the SpA criteria by ASAS particularly for axial SpA, is an important step for early diagnosis and better management of these patients.