Antigliadin and antiendomysial antibodies in children with Down's syndrome

Systematic review: worldwide variation in the frequency of coeliac disease and changes over time

BACKGROUND

Coeliac disease (CD), originally thought to be largely confined to Northern Europe and Australasia and uncommon in North America and the Middle East, is now recognised to be equally common in all these countries. It is still thought to be rare in the Orient and Sub-Saharan Africa.

AIM

To assess geographical differences and time trends in the frequency of CD.

METHODS

Medline and Embase searches were conducted on 10 November 2012, from 1946 and 1980 respectively, using the key words: coeliac disease or celiac disease + prevalence or incidence or frequency.

RESULTS

There were significant intra- and inter-country differences in the prevalence and incidence of CD. Only 24 ethnic Chinese and Japanese patients have been reported in the English literature. Of CD-associated HLA DQ antigens, DQ2 occurs in 5-10% of Chinese and sub-Saharan Africans, compared to 5-20% in Western Europe. DQ8 occurs in 5-10% of English, Tunisians and Iranians, but in <5% of Eastern Europeans, Americans and Asians. The prevalence and incidence of both clinically and serologically diagnosed CD increased in recent years. These geographical and temporal differences seem genuine, although variable indices of suspicion and availability of diagnostic facilities are confounding factors.

CONCLUSIONS

Coeliac disease is increasing in frequency, with significant geographical differences. Although few cases have been described to date in the Orient and Sub-Saharan Africa, there is a significant prevalence of HLA DQ2 and wheat consumption is of the same order as that in Western Europe. CD may therefore become more common in the future in these countries.

Evaluation of cytokine polymorphisms (TNFalpha, IFNgamma and IL-10) in Down patients with coeliac disease

BACKGROUND

In Down syndrome there is an increased prevalence of coeliac disease, but the reasons for this association are yet unknown.

AIMS

To evaluate a possible correlation between TNFalpha, IFNgamma and IL-10 genotype polymorphisms with the susceptibility to coeliac disease in Down syndrome patients.

METHODS

Single nucleotide polymorphisms of TNFalpha (-308G-->A promoter region), IFNgamma (+874T-->A promoter region) and IL-10 (-1082G-->A promoter region) have been studied in 10 Down patients with coeliac disease, in 40 Down patients without coeliac disease and in 220 healthy controls. Clinical features were also studied in coeliac disease-Down syndrome patients.

RESULTS

The 10 coeliac disease-Down syndrome patients had a biopsy proven coeliac disease afterward a serological testing positive to antigliadin, antiendomysium and antitransglutaminase antibodies. Intestinal biopsy showed total atrophy in 6/10 and partial villous atrophy in 4/10 of them. All coeliac disease-Down syndrome patients had silent forms of coeliac disease and classical trisomy 21. No significant differences were observed for the IFNgamma and IL-10 polymorphisms in the studied groups. A significant trend for increase of TNFalpha -308A positive frequency was observed in coeliac disease-Down syndrome patients compared to healthy controls (p=0.043).

CONCLUSIONS

Single nucleotide polymorphisms of IFNgamma and IL-10 do not play a role in predisposing Down syndrome patients to coeliac disease, while the TNFalpha -308 allele could be an additional genetic risk factor for coeliac disease in trisomy 21.

Evaluation of coeliac disease serological markers in Down syndrome patients

BACKGROUND

The increased incidence of coeliac disease in patients with Down syndrome makes screening of coeliac disease in this population advisable.

AIM

Evaluation of efficiency of different serological markers to detect coeliac disease in Down syndrome patients.

PATIENTS

A total of 56 Down syndrome patients (aged: 1-17 years) were included in study.

METHODS

Patients were evaluated for both IgG and IgA anti-transglutaminase antibodies and for anti-gliadin IgA and IgG antibodies using either purified omega-gliadin, wheat ethanol extract or commercial gliadin. Patients who had at least one positive result were evaluated for antiendomysium antibodies using either monkey oesophagus or human umbilical cord by indirect immunofluorescence. Coeliac disease was diagnosed by typical histological changes on duodenal mucosa.

RESULTS

Increased levels of at least one anti-gliadin IgA and IgG antibody marker were found in 27 out of 56 cases (26 for IgG and 9 for IgA). 11/56 were positive for IgG anti-transglutaminase antibodies and two of them were also positive for IgA anti-transglutaminase antibodies and anti-endomysium antibodies. These two patients were finally diagnosed as coeliacs. Gliadin antigenic fractions employed produced differences in the performance of the anti-gliadin IgA and IgG antibody test. The use of commercial gliadin or wheat ethanol extract showed low sensitivity in IgA anti-gliadin IgA and IgG antibody determination, whereas good sensitivity and specificity were observed with omega-gliadins. IgG anti-transglutaminase antibodies showed a high proportion of false positive results (9 out of 56), whereas anti-endomysium antibodies and IgA anti-transglutaminase antibodies presented an excellent correlation with presence of active coeliac disease.

CONCLUSIONS

Two out of 56 Down syndrome patients were diagnosed as coeliacs, corresponding to an incidence of 3.6%. The use of omega-gliadin presented the best efficiency in anti-gliadin IgA and IgG antibody determination whereas IgA anti-transglutaminase antibodies and anti-endomysium antibody determination showed an absolute correlation with presence of active coeliac disease.