Respiratory Infections and the Risk of Celiac Disease

BACKGROUND AND OBJECTIVES

The increasing incidence of celiac disease (CD) suggests that common infections before the onset of autoimmune diseases could be an important factor in switching the immune response. We aimed to explore the relationship between early clinical events and the development of CD in genetically predisposed infants.

METHODS

In this study, 373 newborns from families with at least 1 relative with CD were recruited, and human leukocyte antigen DQ2- or DQ8-positive infants were followed up with clinical and serological evaluations. Cross tabulation and odds ratios were used to explore the risk associated with single variables, and logistic regression analysis was performed to determine the variables that contributed to the risk of developing CD. Stepwise discriminant analysis was used to determine which variables could distinguish case patients from controls before diagnosis.

RESULTS

The cumulative incidence of CD in this cohort was 6% at 3 years and 13.5% at 5 years of age, and l34 children (14%) developed CD before the sixth year of life. An analysis of adverse events showed a higher frequency of respiratory tract infections among CD patients during the first 24 months of life. In a stepwise discriminant analysis, which included sex and human leukocyte antigen risk class, only respiratory infections in the second and first years of life significantly contributed to discrimination of case patients versus controls.

CONCLUSIONS

A multivariate model of discriminant analysis showed that the frequency of respiratory infections in the first 2 years of life could distinguish children who developed CD from those who did not.

Introduction of gluten, HLA status, and the risk of celiac disease in children

BACKGROUND

The relationship between the risk of celiac disease and both the age at which gluten is introduced to a child's diet and a child's early dietary pattern is unclear.

METHODS

We randomly assigned 832 newborns who had a first-degree relative with celiac disease to the introduction of dietary gluten at 6 months (group A) or 12 months (group B). The HLA genotype was determined at 15 months of age, and serologic screening for celiac disease was evaluated at 15, 24, and 36 months and at 5, 8, and 10 years. Patients with positive serologic findings underwent intestinal biopsies. The primary outcome was the prevalence of celiac disease autoimmunity and of overt celiac disease among the children at 5 years of age.

RESULTS

Of the 707 participants who remained in the trial at 36 months, 553 had a standard-risk or high-risk HLA genotype and completed the study. At 2 years of age, significantly higher proportions of children in group A than in group B had celiac disease autoimmunity (16% vs. 7%, P=0.002) and overt celiac disease (12% vs. 5%, P=0.01). At 5 years of age, the between-group differences were no longer significant for autoimmunity (21% in group A and 20% in group B, P=0.59) or overt disease (16% and 16%, P=0.78 by the log-rank test). At 10 years, the risk of celiac disease autoimmunity was far higher among children with high-risk HLA than among those with standard-risk HLA (38% vs. 19%, P=0.001), as was the risk of overt celiac disease (26% vs. 16%, P=0.05). Other variables, including breast-feeding, were not associated with the development of celiac disease.

CONCLUSIONS

Neither the delayed introduction of gluten nor breast-feeding modified the risk of celiac disease among at-risk infants, although the later introduction of gluten was associated with a delayed onset of disease. A high-risk HLA genotype was an important predictor of disease. (Funded by the Fondazione Celiachia of the Italian Society for Celiac Disease; CELIPREV ClinicalTrials.gov number, NCT00639444.).

Can food protein induced enterocolitis syndrome shift to immediate gastrointestinal hypersensitivity? A report of two cases

Food protein induced enterocolitis syndrome (FPIES) is a food-related non-IgE-mediated gastrointestinal hypersensitivity disorder. Atypical FPIES is characterized by the presence of specific IgE for the causative food. The guidelines suggested for diagnostic oral food challenge in pediatric patients affected by suspected FPIES are different from the ones for children with IgE-mediated food allergy. We describe two cases of atypical FPIES that turned into IgE-mediated gastrointestinal anaphylaxis. Our experience suggests to adapt OFC according to the outcome of specific IgE for the causative food When causative food-related IgE werepositive, we suggest to follow the guidelines for IgE mediated food allergy.

HLA related genetic risk for coeliac disease

BACKGROUND

Several studies have shown an elevated prevalence of coeliac disease (CD) in sibs of coeliac patients (risk 8-12%).

AIM AND METHOD

We evaluated the risk that sibs of children with CD will also develop CD. This cohort of 188 Italian families was composed of probands with CD, at least one sib and both parents. CD status was determined and human leucocyte antigen (HLA)-DQ genotyping performed in all family members. The study also used a dataset of Italian triads (127 probands and both their parents) also genotyped for HLA-DQ.

RESULTS

The overall risk that a sib of a CD patient will develop the disease was estimated at 10% in this sample. The risk estimate ranged from 0.1% to 29% when HLA-DQ information of the proband, parents and sib was considered. We found a negligible risk (lower than 1%) for 40% of the sibs of probands, a risk greater than 1% but less than 10% for 30%, and finally a high or very high risk (above 25%) in one-third of families.

CONCLUSION

These results make it possible to provide more accurate information to parents with a child with CD about the real risk for another child. An antenatal estimate of the order of risk of CD is now possible. Specific follow-up can thus be offered for babies at high risk.

A family-based study does not confirm the association of MYO9B with celiac disease in the Italian population

Association between Myosin IXB (MYO9B) gene polymorphisms and celiac disease (CD) was recently detected by a case-control association study in the Dutch, but not confirmed in the British and Swedish/Norwegian populations. We tested the association between CD and the three most associated single nucleotide polymorphisms (SNPs) in the Dutch study by the transmission disequilibrium test in the Italian population. A total of 252 pediatric patients and 504 parents were genotyped. No transmission distortion was detected either for the single SNPs or for their haplotypic combinations. Control allele frequencies, calculated from untransmitted alleles, were significantly different from those of the Dutch control population. Conversely, allele frequencies were very similar in Italian, British, Swedish/Norwegian and Dutch patients. In conclusion, MYO9B is not involved in CD susceptibility in the Italian population. The difference with the Dutch result might be explained by an imperfect selection of the Dutch controls.

Concordance, disease progression, and heritability of coeliac disease in Italian twins

BACKGROUND AND AIMS

We adopted the twin method to disentangle the genetic and environmental components of susceptibility to coeliac disease (CD). We estimated disease concordance rate by zygosity and HLA genotypes, discordance times, progression rates to disease, and heritability.

METHODS

We crosslinked the Italian Twin Registry with the membership lists of the Italian Coeliac Disease Association and recruited 23 monozygotic (MZ) and 50 dizygotic (DZ) twin pairs with at least one affected member. Zygosity was assigned by DNA fingerprinting, and HLA-DQ and DR alleles were genotyped. Disease status was ascertained by antiendomysial, anti-human tissue transglutaminase antibodies, and bowel biopsy.

RESULTS

Concordance was significantly higher in MZ (83.3% probandwise, 71.4% pairwise) than in DZ (16.7% probandwise, 9.1% pairwise) pairs. Concordance was not affected by sex or HLA genotype of the co-twin and being MZ was significantly associated with the occurrence of CD (Cox adjusted hazard ratio 14.3 (95% confidence interval 4.0-50.3)). In 90% of concordant pairs the discordance time was <or=2 years. MZ and DZ co-twins had 70% and 9% cumulative probability of having symptomatic or silent forms of CD, respectively, within five years. Under ACE (additive genetic, common, and unshared environmental factors) models, with CD population prevalences of 1/91 and 1/1000, heritability estimates were 87% and 57%, respectively.

CONCLUSION

MZ pairs have a high probability of being concordant, regardless of sex or HLA genotype. Most of the affected co-twins receive a diagnosis within two years. A remarkable proportion of phenotypic variance is due to genetic factors.

The first large population based twin study of coeliac disease

BACKGROUND AND AIMS

The genetic load in coeliac disease has hitherto been inferred from case series or anecdotally referred twin pairs. We have evaluated the genetic component in coeliac disease by estimating the concordance rate for the disease among twin pairs in a large population based study.

METHODS

The Italian Twin Registry was matched with the membership lists of a patient support group. Forty seven twin pairs were recruited and screened for antiendomysial (EMA) and antihuman-tissue transglutaminase (anti-tTG) antibodies; zygosity was verified by DNA fingerprinting and twins were typed for HLA class II DRB1 and DQB1 molecules.

RESULTS

Concordance rates for coeliac disease differ significantly between monozygotic (MZ) (0.86 probandwise and 0.75 pairwise) and dizygotic (DZ) (0.20 probandwise and 0.11 pairwise) twins. This is the highest concordance so far reported for a multifactorial disease. A logistic regression model, adjusted for age, sex, number of shared HLA haplotypes, and zygosity, showed that genotypes DQA1*0501/DQB1*0201 and DQA1*0301/DQB1*0302 (encoding for heterodimers DQ2 and DQ8, respectively) conferred to the non-index twin a risk of contracting the disease of 3.3 and 1.4, respectively. The risk of being concordant for coeliac disease estimated for the non-index twin of MZ pairs was 17 (95% confidence interval 2.1-134), independent of the DQ at risk genotype.

CONCLUSION

This study provides substantial evidence for a very strong genetic component in coeliac disease, which is only partially due to the HLA region.