Deposition of Anti DS (Double stranded) DNA Ab in kidney, skin, choroid plexus and joints is seen in:
First, the core concept here is about systemic lupus erythematosus (SLE) and its pathogenesis. The question is testing knowledge on where anti-dsDNA antibodies deposit and the resulting pathology. I should mention the immune complex deposition leading to inflammation and tissue damage.
Next, explaining why lupus is correct. The presence of anti-dsDNA antibodies is a hallmark of SLE. These antibodies form immune complexes that get deposited in the basement membranes of various organs. The kidneys (glomeruli), skin, choroid plexus, and joints are common sites. The complement system gets activated, leading to inflammation and damage. I should specify the organs and the mechanism.
For the incorrect options, I need to think about other autoimmune diseases. For example, Sjögren's syndrome might involve other antibodies like anti-SSA/SSB. SLE is the only one associated with anti-dsDNA. Maybe options could include Sjögren's, rheumatoid arthritis, or others. Each of these has different antibody profiles and target tissues.
Clinical pearl: Highlight that anti-dsDNA is specific for SLE and its presence in renal deposits is a key diagnostic feature. Also, mention that lupus nephritis is a common manifestation.
I need to structure the explanation with the required sections, using bold labels. Keep each section concise, under the character limit. Make sure the correct answer is clearly stated at the end. Let me check the character count as I go to stay within 2500. Also, use precise terms like "immune complex deposition," "complement activation," and "glomerulonephritis."
**Core Concept**
The question assesses knowledge of systemic lupus erythematosus (SLE) pathogenesis, specifically the role of anti-dsDNA antibodies in immune complex-mediated tissue damage. Anti-dsDNA antibodies are hallmark autoantibodies in SLE, forming immune complexes that deposit in basement membranes of organs like the kidneys, skin, choroid plexus, and joints.
**Why the Correct Answer is Right**
Anti-dsDNA antibodies are highly specific for SLE and are central to its pathophysiology. These antibodies bind to nuclear antigens, forming immune complexes that deposit in basement membranes via the complement system. In the kidneys, this leads to glomerulonephritis (lupus nephritis). Deposition in skin causes cutaneous lupus lesions, in the choroid plexus leads to meningeal inflammation, and in joints results in arthralgia/arthritis. The pattern of deposition aligns with SLE’s systemic vasculitis and immune complex deposition.
**Why Each Wrong Option is Incorrect**
**Option A:** Sjögren’s syndrome is characterized by anti-SSA/SSB antibodies, not anti-dsDNA, and primarily affects exocrine glands.
**Option B:** Rheumatoid arthritis involves anti-citrullinated protein antibodies and rheumatoid factors, targeting synovium, not choroid plexus or kidneys via dsDNA.
**Option C:** Systemic sclerosis (scler