Beyond the Intestinal Celiac Mucosa: Diagnostic Role of Anti-TG2 Deposits, a Systematic Review

Aim: To review the existing literature on the role and significance of intestinal transglutaminase 2 immunoglobulin A deposits (TG2 deposits) in patients with overt celiac disease (CD), potential celiac disease (PCD), and other autoimmune or gluten-related conditions.

Methods: We conducted a systematic review of studies published in English, evaluating presence and characteristics of TG2 deposits in subjects with overt CD, PCD, gluten-related diseases [dermatitis herpetiformis (DH), gluten-ataxia (GA)], autoimmune disorders (type-1 diabetes), and other conditions. Studies were identified through a MEDLINE search (1950–2013).

Results: Twenty-three studies were included in the review. Eleven studies were performed in children. Overall TG2 deposits were present in 100% of adults with overt CD, while in children prevalence ranged from 73.2 to 100%. Six studies with an established definition of PCD were considered, prevalence of deposits ranging from 64.7 to 100%. A single study followed-up PCD patients with repeated biopsies and identified presence of intestinal deposits as the best marker to reveal progression toward villous atrophy. Two studies investigated presence of deposits in DH, reporting prevalence between 63 and 79%. A single study documented TG2 deposits in 100% of patients with GA. In children with type-1 diabetes (T1D), positivity of intestinal TG2 deposits ranged from 25 to 78%.

Conclusion: Transglutaminase 2 IgA deposits seem to be a constant feature in overt CD patients and are frequently detectable in other gluten-related conditions (DH and GA). The vast majority of PCD patients express TG2 deposits at the intestinal level, but no sufficient data are available to exactly define their prognostic role as a marker of evolution toward overt CD. The frequent finding of TG2 deposits in the intestinal mucosa of patients with T1D is an interesting observation deserving further evaluation.

Oats in the diet of children with celiac disease: preliminary results of a double-blind, randomized, placebo-controlled multicenter Italian study

A gluten-free diet (GFD) is currently the only available treatment for patients with celiac disease (CD). Several clinical trials have demonstrated that most celiac patients can tolerate a medium-high quantity of oats without any negative clinical effects; however, the inclusion of oats in GFD is still a matter of debate. In this study, Italian children with CD were enrolled in a 15-month, randomized, double-blind, placebo-controlled multicenter trial. Participants were randomized in two groups following either A-B treatment (6 months of diet “A”, 3 months of standard GFD, 6 months of diet “B”), or B-A treatment (6 months of diet “B”, 3 months of standard GFD, 6 months of diet “A”). A and B diets included gluten-free (GF) products (flour, pasta, biscuits, cakes and crisp toasts) with either purified oats or placebo. Clinical data (Gastrointestinal Symptoms Rate Scale [GSRS] score) and intestinal permeability tests (IPT), were measured through the study period. Although the study is still blinded, no significant differences were found in GSRS score or the urinary lactulose/mannitol (L/M) ratio between the two groups after 6 months of treatment. These preliminary results suggest that the addition of non-contaminated oats from selected varieties in the treatment of children with CD does not determine changes in intestinal permeability and gastrointestinal symptoms.

The Novel Crohn's Disease Marker Anti-GP2 Antibody Is Associated with Ileocolonic Location of Disease

Crohn's disease (CD) is an inflammatory bowel disease (IBD) that can affect the whole gastrointestinal tract. The ileocolonic variant of CD, an inflammation of both the ileum and the large intestine, accounts for up to 50% of the cases with CD, whereas Crohn's ileitis affecting the ileum is diagnosed in about 30%. Crohn's colitis, which is confined to the large intestine and accounts for the remaining 20%, is difficult to distinguish from the large bowel inflammation seen in patients with ulcerative colitis (UC). The pathogenesis of CD is not yet completely understood. Autoimmunity is one factor that can partake in the triggering or modulation of inflammatory processes in IBD. The major zymogen-granule membrane glycoprotein 2 (GP2) has been recently identified as a major autoantigenic target in CD. Interestingly, GP2 is mainly expressed in the pancreas and has also been demonstrated to be a membrane-anchored receptor of microfold cells in the follicle-associated epithelium. Remarkably, GP2 is overexpressed at the site of CD inflammation in contrast to the one in UC. By utilizing novel enzyme-linked immunosorbent assays for the detection of GP2-specific IgA and IgG, the loss of tolerance to GP2 has been associated with a specific clinical phenotype in CD, in particular with the ileocolonic location of the disease.

A case of syndromic neutropenia and mutation in G6PC3

BACKGROUND

A previously unrecognized syndrome with congenital neutropenia and various organ abnormalities has been described recently, caused by mutations in the gene encoding glucose-6-phosphatase, catalytic subunit 3 (G6PC3).

OBSERVATION

A 10-year-old boy from Ecuador suffering from severe neutropenia and multiple nonhematopoietic abnormalities was admitted to our department. We identified a novel mutation in the G6PC3 gene (c. 765_delAG; p.S255fs).

CONCLUSIONS

This is the first case of G6PC3 deficiency in a patient from South America, caused by a novel mutation in the G6PC3 gene. Our results give insights into the molecular and clinical variability of this disease.