This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Gluten-sensitive enteropathy is most strongly associated with - \nSelect and explain. \nA. HLA-DQ2, B. HLA-DR4, C. HLA-DQ3, D. Blood group B', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Almost all individuals with celiac disease share the major histocompatibility complex II\xa0HLA-DQ 2 or HLA - DQ8.\nGliadin is deamidated by the enzyme transglutaminase and deamidated gliadin peptides bind\xa0to DQ2 and DQ8.\nRecognition of these peptides by CD4 + T cells leads to secretion of IFN-γ, which damages the intestinal wall.\n\nPathophysiology\n\nCeliac disease is caused by the action of acidic peptides containing the gliadin fraction of wheat.\nThe basic abnormality is thought to be an increased rate of loss of epithelial cells. Crypt cells show increased activity. This causes hypertrophy of crypt. But even this increased activity cannot keep pace with the loss of cells, resulting in a progressive decrease in height of villi causing villous atrophy\n\xa0The epithelial cells show decreased cytoplasm and mucus\nThe intestinal biopsy shows a decrease in the villas: crypt ratio. Normally the villi are 3-4 times the height of the crypts (ratio of 3-4: 1); in celiac disease, the ratio decreases progressively (partial, subtotal and total villous atrophy). Total villous atrophy is seen in severe celiac disease and is quite characteristic of celiac disease (partial villous atrophy may be seen in many other conditions).', 'role': 'assistant'}]