Which of the following is true about celiac sprue: September 2009
First, the core concept here is celiac disease. It's an autoimmune disorder triggered by gluten in genetically predisposed individuals. The immune response damages the small intestine's villi, leading to malabsorption. The main HLA types involved are HLA-DQ2 and HLA-DQ8.
The correct answer is likely related to the association with HLA types. Let's say the options include HLA-DQ2, which is correct. The other options might mention other HLA types like HLA-B27 (associated with ankylosing spondylitis), HLA-DR3 (maybe linked to other autoimmune conditions), or HLA-A2 (not typically associated with celiac).
Each wrong option needs to be explained. For example, if an option says HLA-B27, that's incorrect because it's not linked to celiac. Another option might claim it's a type I hypersensitivity, which is wrong since celiac is autoimmune, not IgE-mediated.
The clinical pearl should highlight the importance of HLA testing in diagnosis, even though it's not definitive on its own. Also, noting that most patients are HLA-DQ2 positive is key.
I need to structure the explanation with the required sections, making sure each part is concise and fits within the character limit. Check for any possible errors in the reasoning, like mixing up other autoimmune diseases with celiac. Ensure that the explanation is accurate and uses proper medical terminology.
**Core Concept**
Celiac sprue (celiac disease) is an autoimmune disorder triggered by gluten ingestion in genetically susceptible individuals (HLA-DQ2/HLA-DQ8). It causes mucosal damage in the small intestine, leading to malabsorption and systemic symptoms. Diagnosis relies on serology (anti-tTG IgA), biopsy, and response to gluten withdrawal.
**Why the Correct Answer is Right**
The correct option likely states that celiac disease is associated with **HLA-DQ2** (or HLA-DQ8). These HLA class II molecules are present in >90% of celiac patients. Gluten peptides bind to these HLA molecules, activating T-cells and initiating an immune response that destroys intestinal villi. HLA typing is not diagnostic alone but confirms genetic predisposition.
**Why Each Wrong Option is Incorrect**
**Option A:** If it claims celiac is a type I hypersensitivity, this is incorrect. Celiac is a T-cell-mediated (type IV) autoimmune reaction, not IgE-driven.
**Option B:** If it states "associated with HLA-B27," this is wrong. HLA-B27 is linked to ankylosing spondylitis, not celiac disease.
**Option C:** If it mentions "IgE-mediated," this is incorrect. Celiac lacks IgE involvement; it relies on CD4+ T-cells and autoantibodies (anti-tTG, anti-endomysial).
**Clinical Pearl / High-Yield Fact**
Remember: **HLA-DQ2/DQ8 are required for celiac disease**—if absent, celiac is excluded. However, presence alone is