This spotlight article summarises the common rheumatological autoimmune / immune-mediated diseases , clinical presentations and their incidence and prevalence for easy reference
Andrea Di Matteo MD PhD Paul Emery OBE FLSW MA MD FRCP FMedSci Leeds Institute of Rheumatic and Musculoskeletal Medicine , University of Leeds , Leeds , UK
Rheumatological diseases ( including autoimmune and immunemediated diseases ; ARDs ) are a heterogeneous group of conditions with overlapping clinical , laboratory and immunological manifestations . The clinical presentations of many of these diseases have been well-known for several decades but the underlying causes are not fully understood . The common factor is an excessive , self-reactive immune response , i . e ., autoimmunity , which is assumed to be the result of environmental factors interacting with specific polygenic risks for that disease . 1
Autoimmune diseases arise when self-antigen tolerance fails and the immune system attacks normal , healthy tissues . 2 The result is tissue injury , inflammation and organ or system malfunction . In ARDs there is prominent involvement of the joints and peri-articular soft tissues ( i . e ., tendons and entheses ).
In addition to the joint involvement , connective tissue diseases are associated with a number of extra-articular features , including serositis , Raynaud ’ s phenomenon , interstitial lung disease , and glomerulonephritis . 1
As more became known about the underlying pathology of ARDs , the concept of an autoimmune / autoinflammatory disease continuum developed ( see Figure 1 ). 3 At the one end are those diseases that are purely ‘ auto-inflammatory ’ and arise from malfunction / dysregulation of the innate immune system . At the other , are diseases that are purely autoimmune , arising from dysfunction of the adaptive immune system ; however , many conditions exhibit mixed features of immune dysregulation . ARDs appear to result from an interplay between factors including genetic susceptibility , environmental factors and hormonal changes , amongst others .
This article focuses mainly on the common ARDs ( rheumatoid arthritis ( RA ), ankylosing spondylitis ( AS ) and psoriatic arthritis ( PsA )) but , given the overlapping nature of the clinical manifestations , will also briefly consider a broader spectrum of ARDs . Table 1 summarises the hallmarks and clinical presentations of these diseases .
Rheumatoid arthritis Rheumatoid arthritis ( RA ), the most common of the inflammatory arthritides , is a chronic , systemic , inflammatory arthritis that affects all synovial joints but characteristically the small joints of hands and feet , and is usually symmetrical . Untreated , it causes bone and cartilage destruction . Multimobidity is highly prevalent in RA . 4
Incidence / prevalence It is estimated that about 1.5 men and 3.6 women per 10,000
FIGURE 1
The immunological disease continuum
Autoinflammatory Mixed Autoimmune
Characterised by : Tissue infiltration by activated immune cells Increased pro-inflammatory cytokines Elevated acute phase proteins
Characterised by : Autoantibodies and tissue infiltration by activated immune cells Increased pro-inflammatory cytokines ( interleukin ( IL ) -1 , -6 , -17 , tumour necrosis factor )
Characterised by : Autoantibodies and tissue infiltration by activated immune cells
For example , Giant cell arteritis
Psoriatic arthritis Ankylosing spondylitis
Systemic lupus erythematosus Sjögren ’ s syndrome Systemic sclerosis Rheumatoid arthritis ANCA-associated vasculitis
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