The strong association of the human MHC class I allele HLA‑B27 with the development of the chronic inflammatory disease ankylosing spondylitis (AS) is clear and has been known for over three decades. Despite this, it is far from clear how HLA‑B27 is directly involved in AS. In recent years...

Chronic inflammation of musculoskeletal structures is the most prominent disease manifestation of SpA. More specifically, the axial disease affects the spine, the sacroiliac joints and the hips. Peripheral disease includes peripheral arthritis, with a preference for asymmetrical inflammation of...

The discovery of the association between spondyloarthritis (SpA) and HLA‑B27 inevitably turned the spotlight on T‑lymphocytes as the cells which recognize peptide antigens within the binding groove of the HLA‑B27 molecule and then carry out effector functions. These include cytolysis,...

Animal models are available for the study of several different aspects of spondyloarthritis. The models include naturally occurring spontaneous disorders in primates and rodents, spontaneous disorders in transgenic or gene‑deleted rodents and induced disorders in rodents. Areas of investigation...

The authors describe the main clinical and radiological findings of common enthesopathic disorders—Spondylarthritis (SpA), Chondrocalcinosis/calcium pyrophosphate dehydrate crystal deposition disease (CPPD CDD) and Diffuse Idiopathic Skeletal Hyperostosis (DISH), stressing similarities and...

Peptide binding is a central biological property of HLA‑B27. The availability of HLA‑B27 subtypes differentially associated to ankylosing spondylitis provides a unique tool to explore the relationship between peptide specificity and pathogenetic potential. Many studies have focused on...

Efforts to identify genes other than HLA‑B27 in AS have been driven by the strength of the evidence from genetic epidemiology studies indicating that HLA‑B27, although a major gene in AS, is clearly not the only significant gene operating. This is the case for both genetic...

Ankylosing spondylitis (AS) and other forms of seronegative spondylarthritis (SpA) are characterized by two major processes in joints‑ the first is chronic inflammation and the second is progressive ankylosis. Both features go hand‑in‑hand and determine the clinical picture of...

HLA‑B27 is a risk factor closely associated to spondyloarthropathies (SpA). One form of SpA is reactive arthritis (ReA), which develops as a complication after certain bacterial infections (e.g., Salmonellae, Yersiniae, Shigellae, Campylobacteriae and Chlamydiae). The development of...

Amongst the spondyloarthropathies (SpA), the relationship of host susceptibility and environmental triggers is best seen in reactive arthritis (ReA). There are several points from the clinical studies of ReA which highlight important unresolved issues in the pathogenesis. Innate and adaptive...

A characteristic feature of the spondyloarthropathies is inflammation at tendon or ligament attachment sites. This has traditionally been viewed as a focal abnormality, even though the inflammatory reaction intrinsic to enthesitis may be quite extensive. We argue that the diffuse nature of the...

Osteoporosis or rheumatoid arthritis are bone diseases affecting hundreds of millions of people worldwide and thus pose a tremendous burden to health care. Ground‑breaking discoveries made in basic science over the last decade shed light on the molecular mechanisms of bone metabolism and bone...

The study of biomarkers in spondyloarthropathy (SpA) has emerged to be a very important field of research. This is particularly because the two commonly used biomarkers, erythrocyte sedimentation rate (ESR) and C‑reactive protein (CRP), are of very low sensitivity and specificity. The second...

HLA‑B27 plays a central role in the pathogenesis of many spondyloarthropathies and in particular ankylosing spondylitis. The observation that the HLA‑B27 heavy chain has a tendency to misfold has raised the possibility that associated diseases may belong in a rapidly expanding category of...

HLA‑B27 (B27) is strongly associated with spondyloarthopathy. The classical role of B27 is to present peptides from intracellular pathogens as a heterotrimeric complex with β2 microglobulin for recognition by the T‑cell receptor (TCR) of CD8 T‑cells. In addition to heterotrimers, B27 can...

In order to measure disease activity, progression and response to therapy, it is important to use accurate, reliable and feasible outcome measures that can ideally be used in longitudinal cohorts, clinical trials and clinical practice. With emerging therapies, the focus on the methodology of...

Structural and thermodynamic properties of HLA‑B27 molecules provide the basis for their function within the immune system and are probably also central for the understanding of the pathology of HLA‑B27‑associated diseases such as ankolysing spondylitis (AS). Several HLA‑B27 alleles are...

The role of imaging in the evaluation and management of SpA has experienced a resurgence of interest with the introduction of MRI and more sophisticated sonographic technologies. Several approaches have been developed to score plain radiographic abnormalities in the spine and sacroiliac joints of...

HLA‑B27 family comprehends some alleles strongly associated with Ankylosing Spondylitis (AS) and some others that are not. A comparative analysis at genetic and functional level is likely to give a clue to the understanding of disease pathogenesis. Here, we summarize our recent studies on the...

Bone loss is a common finding in the spondyloarthropathies. It may be localized and present as erosions or be generalized and cause osteoporosis. The pathogenesis of bone loss in the spondyloarthropathies is yet to be fully understood. There is however increasing evidence to support a role for...

Cellular activity of Natural killer cells (NK cells) is defined by the balance between activating and inhibitory signals coming from their receptors. With respect to this response, Killer immunoglobulin‑like receptors (KIR) are unique because of their diversity and capacity to recognize...

HLA‑B27 represents a family of 38 closely related cell surface proteins (encoded by the alleles HLA‑B*2701‑39) called subtypes of HLA‑B27, most of which have evolved from the ubiquitous HLA‑B*2705 (specifically the B*27052 allele).1‑25 HLA‑B27 subtypes are largely characterized by...

Ankylosing spondylitis (AS) is the major subtype and a major outcome of an interrelated group of rheumatic diseases now named as spondyloarthritides (SpA). The most important clinical features of this group are inflammatory back pain (IBP), asymmetric peripheral oligoarthritis, predominantly of...