HPE Autoimmune disease: The fundamentals | Page 22

disease ), latent ( which includes both symptoms of the typical and silent form ) or potential ( having symptoms of typical and silents forms but more reduced ). 18

Non-responsive coeliac disease has persistent symptoms and enteropathy that do not respond after 6 – 12 months on a self-reported gluten-free diet . 19
Refractory coeliac disease has persistent or recurrent symptoms and villous atrophy on duodenal biopsy , despite strict adherence to a gluten-free diet for at least 12 months . 19
Alongside genetic predisposition and gluten exposure , loss of intestinal barrier function , a pro-inflammatory innate immune response triggered by gluten and an imbalanced gut microbiome all appear to be important elements of the autoimmune response in coeliac disease . 17
Some 27 % of people with coeliac disease present with classical symptoms of diarrhoea , weight loss and malabsorption but 21 % have no symptoms and 52 % present with non-classical symptoms . 17 Women are often diagnosed at an earlier age than men and present more often with constipation , bloating , and iron-deficiency anaemia . 1
Complications are rare with coeliac disease – occurring in about 1 % of people diagnosed – but can include hyposplenism , intestinal lymphoma and ulcerative jejunoileitis . 17
Incidence and prevalence In western countries , the prevalence of coeliac disease is around 1 % with serological screening of the general population and 0.6 % in histologically confirmed cases ; however , it is believed to be underdiagnosed 19 and only 36 % of people with the condition are currently clinically diagnosed . 20 It affects all age groups , including the elderly , with more than 70 % of new cases diagnosed in people over 20 years of age . Coeliac disease is diagnosed more frequently in women than in men . A metaanalysis of 50 studies found that the global pooled female incidence was 17.4 per 100,000 person-years , compared with 7.8 in males . 21
In common with other autoimmune diseases , coeliac disease has a strong hereditary component . There is high familial recurrence ( 10 %– 15 %) and a concordance ( 75 %– 80 %) among monozygotic twins . 17
Genetic susceptibility Coeliac disease occurs in genetically susceptible individuals who have HLA-DQ8 or HLADQ2 . Approximately 25 %– 35 % of the general population has HLA-DQ2 / DQ8 but only 3 % of these will go on to develop coeliac disease . 17
Intestinal microbial flora Studies have shown an association between coeliac disease and changes in the composition of the gut microbiome . However , further investigations to define if , and how , the composition of the microbiota and metabolomic profiles might influence the onset of coeliac disease in genetically susceptible subjects are required . 17
Environmental factors In coeliac disease , exposure to dietary gluten causes the immune system to attack host tissues ( in this case , the small bowel mucosa ), damaging the intestinal villi in the small bowel . The consequent
Current and future research will further improve understanding and point the way to new options for treatment and / or prevention of these debilitating conditions . reduction in absorbing surface can lead to malabsorption of nutrients .
Key components of gluten are the gliadins , which are complex proteins rich in prolines and glutamines and which can only be digested partially by intestinal enzymes . The resultant product of this partial digestion triggers host responses ( such as increased gut permeability and innate and adaptive immune responses ). 17 Moreover , there is evidence that gluten can also cross the intestinal barrier once tolerance to gluten has been broken . 17
Immune dysregulation tTG is believed to play a key role in the pathogenesis of coeliac disease . It enhances the immunostimulatory effect of gluten and acts as a target autoantigen in the immune response . Gliadin peptides are excellent substrates for tTG , and the resulting deamidated peptides have a much greater affinity for HLA-DQ2 and HLA-DQ8 . 22
Conclusions Current thinking suggests that the main autoimmune gastrointestinal diseases involve an interplay between genetic predisposition , environmental factors and the gut microbiome , thereby resulting in inflammatory disease and gut malfunction . Current and future research will further improve understanding of these factors and point the way to new options for treatment and / or prevention of these debilitating conditions .
References 1 Al Ruweidi M et al . Autoimmune Diseases of the GI Tract Part I : Etiology and Pathophysiology . Immunology of the GI Tract – Recent Advances [ Internet ]. 2022 Dec 21 . 2 Goodnow CC . Multistep pathogenesis of autoimmune disease . Cell 2007 ; 130 ( 1 ): 25 – 35 . 3 Zheng D , Liwinski T , Elinav E . Interaction between microbiota and immunity in health and disease . Cell Res 2020 ; 30:492 – 506 . 4 Fasano A . All disease begins in the ( leaky ) gut : role of zonulin-mediated gut permeability in the pathogenesis of some chronic inflammatory diseases . F1000Res 2020 Jan 31 ; 9 . 5 Hammer T , Langholz E . The epidemiology of inflammatory bowel disease : balance between East and West ? A narrative review . Dig Med Res 2020 ; 3:48 . 6 Fletcher J et al . The Role of Vitamin
D in Inflammatory Bowel Disease : Mechanism to Management . Nutrients 2019 May 7 ; 11 ( 5 ): 1019 . 7 Danese S , Sans M , Fiocchi C . The CD40 / CD40L costimulatory pathway in inflammatory bowel disease . Gut 2004 ; 53:1035 – 43 . 8 Yamamoto S , Ma X . Role of Nod2 in the development of Crohn ’ s disease . Microbes Infect 2009 ; 11:912 – 18 . 9 Kalla R et al . Crohn ’ s disease . BMJ 2014 ; 349:1 – 11 . 10 Peyrin-Biroulet L et al . The natural history of adult Crohn ’ s disease in population-based cohorts . Am J Gastroenterol 2010 ; 105 ( 2 ): 289 – 97 11 Ruemmele FM et al . Consensus guidelines of ECCO / ESPGHAN on the medical management of pediatric Crohn ’ s disease . J Crohn ’ s Colitis 2014 ; 8 ( 10 ): 1179 – 207 . 12 Bewtra M et al . Crohn ’ s disease and ulcerative colitis are associated with elevated standardized mortality ratios :
a meta-analysis . Inflamm Bowel Dis 2013 ; 19 ( 3 ): 599 – 613 . 13 Ford AC , Moayyedi P , Hanauer SB . Ulcerative colitis . BMJ 2013 ; 346:1 – 9 . 14 Turner D et al . Management of paediatric ulcerative colitis , Part 1 : Ambulatory care - an evidence-based guideline from European Crohn ’ s and Colitis Organization and European Society of Paediatric Gastroenterology , Hepatology and Nutrition . J Paediatr Gastroenterol Nutr 2018 ; 67 ( 2 ): 257 – 91 . 15 Sarlos P et al . Genetic update in inflammatory factors in ulcerative colitis : Review of the current literature . World J Gastrointest Pathophysiol 204 ; 5 ( 3 ): 304- 21 . 16 Shen ZH et al . Relationship between intestinal microbiota and ulcerative colitis : Mechanisms and clinical application of probiotics and faecal microbiota transplantation . World J Gastroenterol 2018 ; 24:5 – 14 . 17 Caio G et al . Celiac disease : a
comprehensive current review . BMC Med 2019 ; 17:142 . 18 Perrotta G , Guerrieri E . Celiac disease : definition , classification , historical and epistemological profiles , anatomopathological aspects , clinical signs , differential diagnosis , treatments and prognosis . Proposed diagnostic scheme for celiac disease ( DSCNC ). Arch Clin Gastroenterol 2022 ; 8 ( 1 ): 008-019 . 19 National Institute for Health and Care Excellence . Coeliac disease . Last revised May 2020 . https :// cks . nice . org . uk / topics / coeliac-disease / ( accessed Feb 2023 ). 20 Coeliac UK . www . coeliac . org . uk / home / ( accessed March 2023 ). 21 King JA et al . Incidence of celiac disease is increasing over time : a systematic review and meta-analysis . Am J Gastroenterol 2020 ; 115:507 – 25 . 22 Di Sabatino A et al . The function of tissue transglutaminase in celiac disease . Autoimmun Rev 2012 ; 11 : 746 – 53 .
22 | hospitalpharmacyeurope . com