A chronic malabsorptive disease of the small intestine
resulting from ingestion of gluten.
Celiac Sprue; Gluten-Sensitive Enteropathy; Herter
Disease; Herter-Heubner Disease.
For symptomatic gluten-sensitive enteropathy, the
incidence is 1:150-1000 in Europe, but a greater proportion of individuals
(1:200-400) may have clinically silent disease. The incidence appears to be
much lower in the black and Asian population, which is explained by a lower
frequency of human leukocyte antigen (HLA)-DQ2 or HLA-DQ8.
Multifactorial. The causative genetic
component involves an assortment of major histocompatibility complex genes
interacting with environmental factors. Celiac disease is the first
HLA-associated disease for which the “at-risk genotypes” have been
delineated. In the vast majority (>93%) of patients with celiac disease,
genetic susceptibility has been associated with the HLA-DQ2 heterodimer,
encoded by the DQA1*0501 and DQB1*02 genes. The remaining minority not
expressing DQ2 is positive for DR4 and shows the DQ8 heterodimer, which is
encoded by DQA1*0301/DQB1*0302 genes. The two heterodimers DQ2 and DQ8 are
located on the surface of antigen-presenting cells and are involved in
binding of peptides to be presented to CD4+ T lymphocytes. This association
supports the importance of CD4+ T lymphocytes in the pathogenesis of celiac
disease, as a T-cell-mediated inflammatory response in the proximal small
bowel is made responsible for the intestinal problems.
The mucosal lesion represents an immunologically
mediated injury triggered by gluten. The amino acid residue of gliadin
triggers the abnormal immune response. Gluten is found in wheat, rye,
barley, triticale, and oats. The alcohol-soluble prolamine fraction is the
component of gluten that is responsible for the symptoms of celiac disease.
Depending on the cereal, this prolamine fraction has different names:
gliadin in wheat, secalin in rye, avenin in oats, and hordein in barley
(newer research suggests avenin is tolerated). Tissue transglutaminase,
the major target of autoantibodies in celiac disease, converts glutamine
residues of gluten to glutamic acid. This deamination results in
significantly increased DQ binding and T-cell recognition.
Malabsorption usually begins at approximately 4 to
20 months of age (although later onset has been reported), but 10 to 20% of
patients become “tolerant” to gluten during adolescence. The disease is
permanent, even if no symptoms are present. The best combination of
serologic tests for the diagnosis is anti-gliadin IgA, anti-gliadin IgG, and
anti-endomysium IgA. The high serum count of intraepithelial lymphocytes
suggests activated mucosal cell-mediated immunity. The final diagnosis of
celiac disease must always rely on the results of an intestinal biopsy
showing villous atrophy. Serologic tests usually are performed at the onset
of clinical symptoms. If the results are positive, then an intestinal biopsy
is indicated to confirm the diagnosis. Serologic tests can be used to
control the response to treatment with a gluten-free diet.
Clinical signs start in early infancy a few weeks
after a diet containing gluten is added to breast-feeding. Intestinal
symptoms are variable, including diarrhea, nausea, vomiting, bloating,
steatorrhea, and constipation. Other features include failure ...