In addition to imposing a significant burden on patients , immune-mediated diseases are associated with increased healthcare utilisation and cause significant socioeconomic impact due to the burden on healthcare systems as well as loss of work productivity for patients
Alain Astier PharmD PhD French Academy of Pharmacy , Faculty of Pharmacy , Paris , France
Immune-mediated diseases ( IMIDs ) represent a group of disorders that are associated with a dysregulated immune system . 1 , 2 These common and clinically diverse disorders share underlying inflammatory pathways , and cause systemic inflammation and multiorgan involvement that results in significant morbidity , reduced quality of life and premature death . 2 – 4 The group comprises more than 100 disorders that may be subdivided into : 1 , 5 , 6
• primary or inherited , and secondary or acquired , immunodeficiencies
• immunoproliferative disorders ( e . g ., multiple myeloma , lymphoma , and leukaemia )
• autoimmune diseases ( e . g ., rheumatoid arthritis [ RA ]), and
• immune hypersensitivities ( i . e ., allergies ).
Inflammatory bowel disease ( IBD ), multiple sclerosis , type 1 diabetes , systemic lupus erythematosus , RA , ankylosing spondylitis and psoriasis , and psoriatic arthritis , are among the most prevalent IMIDs . 7 , 8
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Epidemiology IMIDs affect 5 – 7 % of the Western population . 3 In Spain , the overall prevalence of IMIDs in 2019 was 6.4 %, with psoriasis ( 2.7 %) and RA ( 1.1 %) being the most prevalent . 9 In the UK , it is estimated that approximately 4 million people have at least one autoimmune disease . 10 Multiple factors contribute to the aetiology of these diseases , including environmental factors , diet , infectious agents , and genetic susceptibility . 3 , 11 The incidence of autoimmune diseases is thought to be increasing , and environmental factors , such as changes in the microbiome , are thought to be responsible . 8 , 12
While over 80 % of people diagnosed with autoimmune diseases are women , other IMIDs have a similar prevalence in men and women . Reasons for the gender disparity are thought to include variation within the sex chromosomes and hormonal changes . 6 The incidence and prevalence of IMIDs also differ between ethnic groups . For instance , the highest incidence of SLE is in the African-Caribbean population , whereas the highest incidence of RA is in the South Asian population ; the incidence of other IMIDs ( e . g ., vitiligo and autoimmune thyroid disease ) is also thought to be higher in these ethnic groups . 12
It has also been suggested that there is an earlier age of onset in some ethnic populations as severe disease involving major organs occurs at a younger age . 12 For instance , results of a retrospective population-based primary care study in the UK showed that RA was diagnosed at 47 – 49 years of age in individuals of African-Caribbean , South Asian and Mixed-race / Other ethnicities compared with 56 years in White ethnicities . 12 Reasons for the earlier onset of IMIDs in some ethnic groups are unclear but may involve : presence of a raised inflammatory state at an earlier age in some ethnicities that may lead to accelerated immunesenescence and increased risk of autoimmunity ; differences in the composition of the gut microbiome , which is known to influence systemic inflammation ( e . g ., patients with RA have reduced gut microbiota diversity compared with healthy individuals ); and environmental factors ( e . g ., psychosocial stress , socioeconomic status ). 12
Patient burden IMIDs place a significant burden on patients and can ultimately lead to organ damage and physical disability . 13 Symptoms of individual IMIDs vary but may include pain , chronic fatigue , skin manifestations , and multiorgan dysfunction . 4 The burden of disease varies depending on the disorder and its severity ; up to half of patients with psoriatic arthritis have spinal disease , including axial spondylitis , and many also have debilitating
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