Antigliadin and antireticulin antibodies in children with dermatitis herpetiformis

Bullous dermatoses in childhood: part II

Bullous dermatoses are commonly encountered in childhood practice. Much confusion exists among clinicians because of the similarity of clinical lesions, paucity of relevant literature, and varied nomenclature used for these diseases. For a better understanding of the proposed classification, this second part is a review of diseases with nonhereditary characteristics of subepidermal cleavage and hereditary characteristics with intraepidermal and subepidermal cleavage.

Affinity maturation of immunoglobulin A anti-tissue transglutaminase autoantibodies during development of coeliac disease

Coeliac disease (CD) is an immune-mediated enteropathy triggered by ingestion of wheat gluten and related cereals in genetically predisposed individuals. Circulating immunoglobulin A (IgA) class autoantibodies against tissue transglutaminase (IgA-TGA) are highly specific and sensitive serological markers for CD, which is ultimately confirmed by duodenal biopsy. Although CD is considered a life-long disorder, transient or fluctuating IgA-TGA seropositivity has been observed in asymptomatic individuals on a gluten-containing diet. We set out to explore possible differences in the maturation of IgA-TGA avidity between individuals progressing to CD and subjects remaining healthy despite occasional expression of autoantibodies. We developed a time-resolved fluorometric IgA-TGA assay based on human recombinant tissue transglutaminase (tTG), and further modified the method to also measure urea-dependent avidity of the autoantibodies. We measured the autoantibody titres and avidities of sequential serum samples from 10 children developing CD and 10 children presenting transient or fluctuating autoantibodies. Both the initial titres at seroconversion and peak values of transient/fluctuating IgA-TGA were significantly lower than corresponding autoantibody titres in samples drawn from individuals with progressing CD (P = 0.004 and P = 0.0002, respectively). However, there were no statistically significant differences in the initial or peak avidity index values between the two groups of children. The avidity index values increased during the follow-up period (P = 0.013 for both groups) with no significant difference in the rate of avidity maturation between children with transient/fluctuating IgA-TGA and children developing CD. According to our results, high autoantibody titres have a higher predictive value than avidity maturation of TGA-IgA in screening for CD.

Oats in the treatment of childhood coeliac disease: a 2-year controlled trial and a long-term clinical follow-up study

BACKGROUND

The exclusion of oats from the diet in coeliac disease is controversial.

AIM

To study the long-term safety of oats in the treatment of children with coeliac disease.

METHODS

Altogether 32 children with coeliac disease were enrolled in a 2-year controlled trial. Twenty-three children in remission were randomized either to oats or gluten challenge; when small bowel histological relapse was evident after gluten challenge, a gluten-free diet including oats was started. Furthermore, nine newly detected coeliac patients adopted an oat-containing gluten-free diet. Small bowel mucosal morphology, CD3+, alphabeta+ and gammadelta+ intraepithelial lymphocytes, human leucocyte antigen (HLA) DR expression and coeliac serology were determined. After the trial, the children were allowed to eat oats freely; follow-up was extended up to 7 years.

RESULTS

In coeliac children in remission, oats had no detrimental effect on intestinal histology or serology during the 2-year trial. In contrast, the gluten-challenge group relapsed after 3-12 months. Complete recovery from the disease was accomplished in all relapsed and newly detected patients on an oat-containing gluten-free diet. After the trial, 86% of the children preferred to consume oats and they all remained in remission.

CONCLUSION

In most children with coeliac disease, long-term consumption of oats is well tolerated, and it does not result in small bowel mucosal deterioration or immune activation.

Binding to human jejunum of serum IgA antibody from children with coeliac disease

Jejunal histology and the presence of serum IgA antibodies (JAB) binding to human jejunum in vitro were studied in 139 children with severe malabsorptive symptoms. Among 33 children with confirmed coeliac disease (ESPGAN criteria), 13 (93%) of 14 sampled before starting on a gluten-free diet had JAB, none of 21 sampled had JAB while on a gluten-free diet of long duration, and 90% of 30 sampled during gluten challenge had JAB. 53 children had severe jejunal villous atrophy (probable coeliac disease): 71% of those younger than 2 years and 94% of those aged 2-18 years had JAB during gluten intake. JAB could not be detected in 53 disease control patients (normal jejunal histology) and in 3 coeliac disease patients with selective IgA deficiency. Simultaneous determination of antigliadin (AGA) and antiendomysium (EMA) levels, and gliadin and tissue absorption studies, showed that JAB and AGA are different, whereas JAB and EMA are probably identical. IgA JAB could be the target-organ-related autoantibodies in coeliac disease.

Comparison of IgA-class reticulin and endomysium antibodies in coeliac disease and dermatitis herpetiformis

The occurrence of IgA class reticulin and endomysium antibodies was examined with the standard immunofluorescence method in coeliac disease and dermatitis herpetiformis. Similar high antibody frequencies were detected in 32 untreated adults (91%) and 18 children (100%) with coeliac disease and in 14 dermatitis herpetiformis patients with subtotal villous atrophy (reticulin antibodies 93% and endomysium antibodies 100%). The specificity of IgA class reticulin antibodies and endomysium antibodies was high because all 45 adult patients with ulcerative colitis or Crohn's disease, 24 non-coeliac children with abdominal symptoms and 99/100 healthy blood donors were negative for these antibodies. The only positive blood donor had both IgA class reticulin antibodies and endomysium antibodies but also she was found to have coeliac disease. IgA class reticulin antibodies and endomysium antibodies declined in parallel during treatment with a gluten free diet and increased on gluten challenge. This suggests that these antibodies can be used to screen for gluten sensitive enteropathy and to monitor dietary treatment. To characterise the tissue specificity of reticulin antibodies and endomysium antibodies four positive sera were absorbed with human and several rodent liver homogenates. Absorption with rat or other rodent livers removed the rodent-specific reticulin antibodies but not the reticulin antibodies detectable with human tissues or the endomysium antibodies detectable with monkey oesophagus. These results show that reticulin antibodies can be divided into the rat and human subtypes. The human subtype could not be separated from endomysium antibodies in the present absorption experiments.

IgA anti-endomysial antibodies in dermatitis herpetiformis: correlation with jejunal morphology, gluten-free diet and anti-gliadin antibodies

Circulating IgA-class anti-endomysium antibodies (EmA) can be detected by indirect immunofluorescence on monkey oesophagus sections. We found EmA in 22 (76%) of 29 patients with dermatitis herpetiformis (DH) on a normal, gluten-containing diet. The highest frequency (100%) of EmA was observed in patients with sub-total villous atrophy. IgA-class antigliadin antibodies (AGA) were found using an ELISA method in 59% of 29 DH patients and in 86% of those with sub-total villous atrophy. There was a significant correlation between EmA titres and AGA levels in individual patients. Gluten-free diet (GFD) treatment caused a rapid decrease in EmA titres; only three of the 12 patients still showed raised EmA after 6-12 months on a GFD and two of these three had failed to adhere to a strict diet. In contrast, no decrease in EmA titres occurred in four patients maintained on a normal diet, and two of the three patients with initially negative EmA developed positive titres when continuing on a normal diet. These results show that both IgA-class EmA and AGA are good indicators of jejunal damage in DH. The rapid fall of EmA titres after gluten withdrawal indicates that this test is also useful for monitoring a patient's adherence to a GFD.