New developments in celiac disease

Frequency of HLA-DQA1*0501 and DQB1*0201 alleles in patients with coeliac disease, their first-degree relatives and controls in Jordan

BACKGROUND

The primary genetic marker associated with coeliac disease (CD) is the HLA-DQ2 molecule, encoded by the DQA1*0501 and DQB1*0201 genes.

AIM

To investigate the frequency of HLA-DQA1*0501 and DQB1*0201 alleles in Jordanian patients with CD and their first-degree relatives.

METHODS

An allele-specific DNA-based PCR-sequence-specific primer was used to investigate DQA1*0501 and DQB1*0201 alleles in 44 CD patients, 47 first-degree relatives and 53 healthy controls.

RESULTS

The mean age of the patients at the time of diagnosis was 13.5 years (range 1-39) and at the time of the study was 19.3 years (range 5-42). The DQA1/B1 (0501; 0201) haplotype was present in 80% of patients and 66% of first-degree relatives compared with 32% of controls (p<0.0001 and <0.01, respectively). The remaining 20% of CD patients who were negative for the DQ2 molecule carried the DQB1*0201 allele only. A statistically significant difference was detected in the DQ2 hetero-dimer frequency between CD patients, their first-degree relatives and controls with a higher frequency in the patients group (p<0.001).

CONCLUSION

The significant differences in the frequency of DQA1*0501, DQB1*0201 alleles in CD patients and their first-degree relatives compared with the control group demonstrated the important role of these alleles in the development of CD in the Jordanian population.

The mucocutaneous manifestations associated with celiac disease in childhood and adolescence

This study was performed to detect the prevalence of mucocutaneous manifestations of celiac disease in childhood and adolescence and to investigate the relationship between these findings and duration of disease and a gluten-free diet. The study included 55 children and adolescents with a mean age of 10.0 +/- 4.61 years (2-19 years). Mucocutaneous manifestations were evaluated with respect to age, gender, duration of illness, and of gluten-free diet and compliance with this diet. Cutaneous, mucosal, nail, and hair findings were detected in 74.5%, 27.3%, 20.0%, and 7.3% of patients, respectively. The most prevalent dermatologic diagnosis was xerosis (69.1%). No significant relationship was detected between the cutaneous findings and the duration of illness (p > 0.05). However, the duration was longer in patients with mucosal findings compared to those without mucosal findings (p < 0.05). It was found that all patients without cutaneous findings were on a strict gluten-free diet (p < 0.05). Ours is one of the few studies describing skin findings in children with celiac disease. We believe that both pediatricians and dermatologists should be aware of the various mucocutaneous manifestations of celiac disease, because a careful skin, mucosa, nail, and hair examination may lead to a diagnosis of celiac disease, particularly in atypical presentations.

VSL#3 probiotic preparation has the capacity to hydrolyze gliadin polypeptides responsible for Celiac Sprue

The native structure and distribution of gliadin epitopes responsible for Celiac Sprue (CS) may be influenced by cereal food processing. This work was aimed at showing the capacity of probiotic VSL#3 to decrease the toxicity of wheat flour during long-time fermentation. VSL#3 (10(9) cfu/ml) hydrolyzed completely the alpha2-gliadin-derived epitopes 62-75 and 33-mer (750 ppm). Two-dimensional electrophoresis, immunological (R5 antibody) and mass spectrometry analyses showed an almost complete degradation of gliadins during long-time fermentation of wheat flour by VSL#3. Gliadins non-hydrolyzed during fermentation by VSL#3 were subjected to peptic-tryptic (PT) digestion and analyzed by CapLC-ESI-Q-ToF-MS (Capillary Liquid Chromatography-Electrospray Ionization-Quadrupole-Time of Flight-Mass Spectrometry). Search for several epitopes showed the only presence of alpha2-gliadin-fragment 62-75 at a very low concentration (sub-ppm range). Compared to IEC-6 cells exposed to intact gliadins extracted from the chemically acidified dough (control), VSL#3 pre-digested gliadins caused a less pronounced reorganization of the intracellular F-actin which was mirrored by an attenuated effect on intestinal mucosa permeability. The release of zonulin from intestinal epithelial cells treated with gliadins was considerably lower when digested with VSL#3. Agglutination test on K 562 (S) cells showed that the PT-digest of wheat flour treated with VSL#3 increased the Minimal Agglutinating Activity of ca. 100 times. Wheat proteins were extracted from doughs and subjected to PT digestion. Compared to PT-digest from chemically acidified dough, celiac jejunal biopsies exposed to the PT-digest from the dough fermented by VSL#3 did not show an increase of the infiltration of CD3(+) intraepithelial lymphocytes. Proteolytic activity by probiotic VSL#3 may have an importance during food processing to produce pre-digested and tolerated gliadins for increasing the palatability of gluten-free products.

The lectin-cell interaction and its implications to intestinal lectin-mediated drug delivery

Based on the fact that oligosaccharides encode biological information, the biorecognition between lectinised drug delivery systems and glycosylated structures in the intestine can be exploited for improved peroral therapy. Basic research revealed that some lectins can mediate mucoadhesion, cytoadhesion, and cytoinvasion of drugs. Entering the vesicular pathway by receptor mediated endocytosis, part of the conjugated drug is accumulated within the lysosomes. Additionally, part of the drug is supposed to be transported across the epithelium. Moreover, factors probably adversely influencing feasibility of the concept such as toxicity, immunogenicity, and intestinal stability of plant lectins are discussed. As exemplified by lectin-grafted prodrug and carrier systems, this strategy is expected to improve absorption and probably bioavailability of poorly absorbable drugs, peptides and proteins as well as therapeutic DNA.