Genetic difference in HLA-DR phenotypes between coeliac disease and transitory gluten intolerance

High Incidence of Celiac Disease in a Long-term Study of Adolescents With Susceptibility Genotypes

BACKGROUND & AIMS

Little is known about the incidence of celiac disease in the general population of children in the United States. We aimed to estimate the cumulative incidence of celiac disease in adolescents born in the Denver metropolitan area.

METHODS

We collected data on HLA-DR, DQ genotypes of 31,766 infants, born from 1993 through 2004 at St. Joseph's Hospital in Denver, from the Diabetes Autoimmunity Study in the Young. Subjects with susceptibility genotypes for celiac disease and type 1 diabetes were followed up for up to 20 years for development of tissue transglutaminase autoantibodies (tTGA). Outcomes were the development of celiac disease autoimmunity (CDA) or celiac disease. CDA was defined as persistence of tTGA for at least 3 months or development of celiac disease. Celiac disease was defined based on detection of Marsh 2 or greater lesions in biopsy specimens or persistent high levels of tTGA. For each genotype, the cumulative incidence of CDA and celiac disease were determined. To estimate the cumulative incidence in the Denver general population, outcomes by each genotype were weighted according to the frequency of each of these genotypes in the general population.

RESULTS

Of 1339 subjects followed up, 66 developed CDA and met criteria for celiac disease and 46 developed only CDA. Seropositivity for tTGA resolved spontaneously, without treatment, in 21 of the 46 subjects with only CDA (46%). The estimated cumulative incidence for CDA in the Denver general population at 5, 10, and 15 years of age was 2.4%, 4.3%, and 5.1%, respectively, and incidence values for celiac disease were 1.6%, 2.8%, and 3.1%, respectively.

CONCLUSIONS

In a 20-year prospective study of 1339 children with genetic risk factors for celiac disease, we found the cumulative incidence of CDA and celiac disease to be high within the first 10 years. Although more than 5% of children may experience a period of CDA, not all children develop celiac disease or require gluten-free diets.

Association of human leucocyte-DR and DQ antigens in coeliac disease: a family study

BACKGROUND AND AIMS

No family studies regarding the association of coeliac disease with the human leucocyte antigen (HLA)-DQ locus are available. Moreover, no HLA studies have been carried out in coeliac disease patients from India. The aim of this study was to study the HLA class II (DR and DQ) antigens in children with coeliac disease and in their first-degree relatives.

METHODS

Fifteen children with coeliac disease and their first-degree relatives (birth parents of all the coeliac disease patients and fifteen siblings) were studied. A group of 123 healthy unrelated and ethnically matched subjects were used as controls. The HLA-DR and -DQ typing was carried out by a complement-dependent microlymphocytotoxicity assay. The transmission disequilibrium test was used for analysis of results.

RESULTS

There was no association of coeliac disease with DR phenotypes. Ninety-three per cent of patients (14/15) carried the DQ2 allele. DQ2 was transmitted in 15 of 19 informative cases (transmission probability of 79%, chi2 6.368 with 1 df, nominal P=0.012 and P value corrected for multiple test=0.035). The haplotype relative risk associated with DQ2 was 5.71 (95% confidence interval 1.71-16.28).

CONCLUSION

Coeliac disease in Indian children is predominantly associated with HLA-DQ2.

Genetic differences in HLA-DQA1* and DQB1* allelic distributions between celiac and control children in Santiago, Chile

Celiac disease is a permanent gluten intolerance strongly associated with HLA class II antigens. The over presentation of particular HLA alleles and haplotypes has been described in several populations. Different lines of evidence obtained during the last years suggest that a particular HLA-DQ heterodimer, encoded by the DQA1*0501 and DQB1*0201 genes in cis or trans conformation, confers the primary disease susceptibility. We report the HLA class II allelic distribution and DQA1/ DQB1 genotypes in 62 Chilean celiac patients compared with 124 control subjects in Santiago, Chile. We found a pronounced increase of the "susceptible" alleles :DQA1*0501 (0.480 vs 0.169, Pc < 0.0005), DQB1*0302 (0.430 vs 0.242, Pc = 0.002) and DQB1*0201 (0.250 vs 0.125, Pc = 0.037) in celiac patients in comparison with control children. As for "protective" alleles, we detected a high frequency of DQA1*0101 (0.310 vs 0.160, Pc = 0.01), DQA1*0201 (0.105 vs 0.010, Pc < 0.0075) and DQB1*0301 (0.250 vs 0.100, Pc = 0.010) in controls. In relation to risk haplotypes, the main combination observed was the conformation DQ8 (DQB1*0302/DQA1*0301) over DQ2 (DQB1*0201/DQA1*0501). In conclusion, results show that celiac disease in Chilean patients is primarily associated with DQ8 conformation. This is concordant with the high frequency of DR4 alleles (in linkage disequilibrium with DQB1*0302) detected in Amerind groups in Chile, where DQB1*0302 is more frequent than DQB1*0201.

Peripheral oxygenation and anemia in preterm babies

A measurement of tissue oxygenation may be a better marker of transfusion need than the Hb concentration. Peripheral fractional oxygen extraction, oxygen consumption, and oxygen delivery were measured noninvasively using near infrared spectroscopy in babies, some of whom were given blood transfusions. The above indicators of oxygenation were measured in 96 preterm babies. The decision to transfuse was based on a standard protocol. Transfusions were not considered necessary for babies in group 1 but were given to those in groups 2 (asymptomatic) and 3 (symptoms attributed to anemia). Hb and Hb fraction F (HbF) were measured in each baby. Oxygenation, Hb, and HbF measurements were made again 12-24 h after transfusion, and red cell volume (RCV) was calculated. Fractional oxygen extraction was significantly higher in symptomatic (0.43 +/- 0.06) but not asymptomatic (0.33 +/- 0.05) babies compared with control subjects (0.35 +/- 0.06). Oxygen consumption and oxygen delivery were similar in the three groups before transfusion. After transfusion the mean fractional oxygen extraction fell significantly in symptomatic but not in asymptomatic babies. There was no significant change in either oxygen consumption or oxygen delivery in symptomatic babies. The asymptomatic group had no change in oxygen extraction or oxygen consumption after transfusion, although oxygen delivery increased significantly. Fractional oxygen extraction correlated with HbF (n = 66, r = 0.49, p < 0.001) and RCV (n = 19, r = -0.48, p = 0.04) and there was a weak correlation with Hb (n = 94, r = -0.21, p = 0.04). Peripheral fractional oxygen extraction monitored noninvasively correlated with variables known to determine oxygen availability to the tissues, namely RCV and HbF, and was higher in babies with symptomatic anemia and decreased after transfusion.

Lack of correlation between genotype and phenotype in celiac disease

BACKGROUND

Celiac disease has a wide range of clinical features. The goal of this study was to evaluate whether specific HLA genotypes are associated with particular clinical appearances.

METHODS

One hundred forty-five patients with confirmed celiac disease were oligotyped for DR and DQ HLA genes. Clinical notes, physical examination, and a questionnaire provided their personal data. Patients were grouped into nine genotypic categories, according to the presence of the specific DQ heterodimer DQA1*0501-DQB1*0201 (hence termed alpha0beta0), in single or double dose, and the presence of the DRB4 antigen.

RESULTS

Age at first symptoms and age at beginning of gluten-free diet were not significantly different in the nine groups. The initial symptoms of the disease had a similar distribution in all groups. In twenty-seven patients, disease was diagnosed by family screening: they shared a similar HLA genotype with those who had relevant symptoms. The actual growth status-evaluated by standardized height, percentage of median weight for age, and percentage of median weight for height--was not different in the nine groups. Presence of unusual health complaints was not associated with a specific genotype.

CONCLUSIONS

There is no evidence that clinical features of celiac disease are associated with different HLA genotypes. Genes outside the HLA may play a relevant role.

The spectrum of coeliac disease in children

Coeliac disease is the life-long intolerance to dietary gluten, usually characterized by severe damage to the small-intestinal mucosa. The widespread use of sensitive diagnostic tools, such as the serum anti-gliadin and the anti-endomysial antibodies, has shown not only that coeliac disease is one of the commonest disorders in Western countries but also that this condition is characterized by a higher degree of clinical variability than previously thought (typical, atypical and silent forms). The existence of a latent-potential coeliac disease and even a gluten-sensitive disease with immunological activation of an otherwise normal small-intestinal mucosa has recently been postulated. An increased prevalence of coeliac disease in a number of other disorders has also been reported in both children and adults. The reasons for such a wide clinical heterogeneity are still poorly understood but are likely to depend on both genetic and environmental factors. Further investigations are required to evaluate the impact of undiagnosed, clinically milder forms of coeliac disease on the well-being of the population.