Serological markers identify histologically latent coeliac disease among first-degree relatives

BACKGROUND AND AIM

Serological markers detect asymptomatic coeliac disease among first-degree relatives of patients with sprue. However, some relatives with coeliac disease-related antibodies have 'normal' jejunal mucosa by conventional histology. Whether these serological abnormalities represent false-positives or are consequences of gluten sensitivity is not known. Our aim was to evaluate, through quantitative histology, intestinal biopsies of asymptomatic relatives of probands seeking abnormalities consistent with latent coeliac disease.

MATERIALS

Fifty-nine intestinal biopsies obtained from asymptomatic relatives were evaluated; 40 samples were suitable for histological quantification. Seven samples showed severe mucosal atrophy (coeliac disease) and 33 were considered as 'normals'. In the 'normal' group, nine samples were obtained from patients with one or more positive serological tests and 24 from those with negative tests. Morphometry was compared for samples obtained from healthy control individuals (n = 10) and for those from coeliac patients (n = 7).

METHODS

Serological tests used were: antigliadin antibodies type immunoglobulin (Ig)A and IgG (enzyme-linked immunosorbent assay), antirrecticulin antibody (immuno-fluorescence) and endomysial antibody (immunofluorescence). Biopsy samples were obtained with endoscopic forceps from the distal duodenum (second portion). Quantitative histology of duodenal biopsies was performed with a computerized image analysis system.

RESULTS

Relatives with positive serology showed shorter villi (P < 0.05) and higher number (P < 0.01) and numerical density (P < 0.01) of intraepithelial lymphocytes in crypts than healthy controls. Numerical density of intraepithelial lymphocytes in crypts in antibody-positive patients was significantly higher than that observed in relatives with negative serology (P < 0.03). Four of nine (44%) relatives with positive serology had a number of intraepithelial lymphocytes in crypts within the range of coeliac disease patients. However, only one patient with negative serology (4%) was in this range.

CONCLUSION

Our study shows quantitative histological evidence that relatives of probands with positive coeliac disease-related serology are not false-positives, and that they should be considered as individuals with latent coeliac sprue.

Screening for asymptomatic celiac sprue in families

We evaluated the reliability of IgA and IgG antigliadin antibodies (AGA-A, AGA-G), antireticulin antibody (ARA), endomysial antibodies (EmA), and alpha 1-antitrypsin clearance (alpha 1-AT CL) in the detection of celiac sprue (CS) in 59 first-degree asymptomatic relatives of celiac patients who had duodenal biopsy. Twenty-four relatives who had normal results of screening tests were selected at random for biopsy; 35 relatives with at least one abnormal test result were biopsied. Eleven relatives were noted to have villous atrophy at biopsy; the diagnosis of celiac sprue was confirmed by histological improvement after gluten-free diet in six. AGA-G, alpha 1-AT CL, and EmA had sensitivities of 73%, 73%, and 64%, respectively, with very high levels of specificity. Sensitivity was improved by the combination of two serological markers (AGA-G + alpha 1-AT CL = 91%; AGA-G + EmA = 82%; EmA + ARA = 82%). Furthermore, combination of EmA and ARA has shown the best specificity and positive predictive value. AGA-G, alpha 1-AT CL, and EmA are reliable individual markers for the detection of asymptomatic celiac sprue. However, a combination of two of them, including ARA, was more sensitive than the individual tests.