Biochemical Abnormalities Among Celiac Disease Patients Referred for Antibody Testing

Celiac disease (CD) is a chronic disease occurring in all age groups and affecting approximately 1% of the population, although many cases of CD remain undiagnosed. This condition is caused by an abnormal immune response in genetically susceptible individuals triggered by the ingestion of gluten proteins from wheat, rye and barley.

Celiac disease primarily affects the small intestine, often leading to malabsorption and micronutrient deficiencies. A small intestinal biopsy with recognition of villus atrophy and inflammation has been the gold standard for diagnosis; however, serological testing is increasingly used in the diagnostic process and screening for CD, mainly by the detection of CD-specific antibodies.

Clinical Scientists at the Copenhagen University Hospital (Copenhagen, Denmark) and their colleagues included in an observational cohort study 706 individuals that had received a positive CD antibody result; 72.7% were women and the mean age was 26 years. The team compared the results of those with CD-positive antibodies with individuals with CD-negative antibodies.

Tissue transglutaminase antibody (IgA) (TTG-IgA), tissue transglutaminase antibody (IgG) (TTG-IgG), deamidated gliadin peptide antibody (IgA) (DGP-IgA) and deamidated gliadin peptide antibody (IgG) (DGP-IgG) were measured in serum by fluorescence enzyme immunoassay (EIA) on the UniCAP 100 and ImmunoCAP 250 platforms (Phadia Laboratory Systems, Thermo Fisher Scientific, Hvidovre, Denmark).

Other variables used from the CopLab database were hemoglobin, erythrocytes, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), transferrin, hematocrit, ferritin, alanine transaminase (ALAT), alkaline phosphate, 25-OH vitamin D, folic acid, cobalamin, C-reactive protein (CRP), reticulocyte, mean corpuscular hemoglobin (ReticMCH), erythrocyte volume, relative distribution width (RDW), and immunoglobulin A.

The investigators reported a most remarkable difference between the groups was the markedly lower ferritin among CD antibody-positive individuals compared with CD antibody-negative individuals (women: 13.8 µg/L versus. 35.9 µg/L; men: 34.3 µg/L versus 80.4 µg/L), Also, CD antibody-positive individuals had a tendency for lower hemoglobin (women: 7.8 mmol/L versus 8.1 mmol/L; men: 8.5 mmol/L versus 8.8 mmol/L). The team reported lower cobalamin and folic acid levels and higher levels of transferrin, alanine transaminase and alkaline phosphate among CD antibody-positive individuals.

Compared with CD-negative individuals, the scientists reported that a greater proportion of tests among CD antibody-positive individuals exhibited hemoglobin (10.2% versus 2.7%), mean corpuscular volume (7.1% versus 2.9%), mean corpuscular hemoglobin concentration (6.8% versus 1.2%) and ferritin (37.6% versus7.6%) below the reference level, while transferrin (20.7% versus 9.5%) was above the reference interval. CD antibody-positive individuals were also more likely to have a deficiency for cobalamin and folic acid.

Line Lund Kårhus, MD, PhD, the lead author of the study, said, “This study identified several biochemical abnormalities associated with celiac disease (CD) antibody positivity in a primary care setting among individuals referred to CD antibody testing. The pattern of abnormalities suggested that micronutrient deficiencies were prevalent among CD antibody-positive individuals.”

The authors concluded that their study showed more measurements below the reference interval for hemoglobin, MCV, MCHC, ferritin, cobalamin and folic acid among the individuals with a positive CD antibody test. The pattern of the included biomarkers suggested that micronutrient deficiencies were common among CD antibody-positive individuals and confirmed malabsorption as a sign of CD. The study was published on April 18, 2022 in the journal Scientific Reports.

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