Non-classical Celiac Disease: Often Missed

Emerging Biomarkers for Screening and Management of Celiac Disease

Celiac disease (CeD) is a chronic, immune-mediated enteropathy that is precipitated by dietary gluten in genetically predisposed individuals expressing HLA-DQ2 and/or HLA-DQ8. In the current clinical practice, there are many serologic studies to aid in the diagnosis of CeD which include autoantibodies like IgA antitissue transglutaminase, antiendomysium, and antideamidated forms of gliadin peptide antibodies. Small intestinal biopsy has long been considered an essential step for the diagnosis of CeD. However, in the recent era, researchers have explored the possibility of CeD screening and diagnosis without endoscopy or biopsy. The newer emerging biomarkers of CeD appear promising in diagnostic evaluation and subsequent monitoring of disease. In this review of literature, we have explored the emerging biomarker-based diagnostic evaluation and monitoring of CeD.

Coeliac disease

Coeliac disease (CD) develops in genetically susceptible individuals who, in response to unclear environmental triggers, develop an immune response triggered by gluten ingestion. It is now recognised as a global disease affecting about 0.7% of the world's population. The clinical presentation ranges from malabsorption to asymptomatic individuals diagnosed by screening high-risk groups. Diagnosis requires the demonstration of small intestinal villous atrophy in the presence of circulating coeliac auto-antibodies and/or an unequivocal response to a gluten-free diet (GFD). Recent guidelines suggest that, in a subset of children, duodenal biopsies can be avoided in the presence of strict symptomatic and serological criteria. While the majority of patients respond to a GFD, up to 20% of patients with CD have persistent or recurrent symptoms. There are several aetiologies for residual or new symptoms in a patient with CD on a GFD, with inadvertent exposure to gluten being the most common. Following a GFD can be challenging for patients with CD and understanding the barriers/challenges faced by patients in maintaining a GFD is crucial for compliance. Abbreviations: AGA: anti-gliadin antibodies; Anti-DGP-ab: anti-deamidated gliadin peptide antibodies; Anti-tTG-ab: anti-tissue transglutaminase antibodies; ATD: auto-immune thyroid disorders; BMD: bone mineral density; CD: coeliac disease; DH: dermatitis herpetiformis; EMA: anti-endomysial antibodies; FDR: first-degree relatives; GFD: gluten-free diet; HbA1c: haemoglobin A1c; HLA: human leucocyte antigen; IBS: irritable bowel syndrome; LMIC: low- and middle-income countries; NPV: negative predictive value; NRCD: non-responsive coeliac disease; POCT: point-of-care tests; SDR: second-degree relatives; SIBO: small intestinal bacterial overgrowth; T1DM: type 1 diabetes mellitus; ULN: upper limit of normal.