C-ANCA is/are associated with: (PGI June 2008)
**Core Concept**
C-ANCA, or cytoplasmic antineutrophil cytoplasmic antibodies, is a type of autoantibody associated with vasculitis, particularly granulomatosis with polyangiitis (GPA). This condition is characterized by inflammation of blood vessels, leading to damage in various organs.
**Why the Correct Answer is Right**
C-ANCA is most commonly associated with granulomatosis with polyangiitis (GPA), a form of vasculitis that primarily affects the respiratory tract and kidneys. The presence of C-ANCA is a strong indicator of GPA, although it can also be seen in other forms of vasculitis. The mechanism behind C-ANCA-associated vasculitis involves the activation of neutrophils and the release of granules, leading to vascular damage and inflammation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because P-ANCA (perinuclear ANCA) is associated with microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA), not C-ANCA.
**Option B:** This option is incorrect because MPO-ANCA (myeloperoxidase-ANCA) is also associated with MPA and EGPA, not C-ANCA.
**Option C:** This option is incorrect because this is not a recognized association with C-ANCA.
**Clinical Pearl / High-Yield Fact**
It is essential to remember that the presence of C-ANCA in a patient with symptoms of vasculitis, particularly those affecting the respiratory tract and kidneys, should raise a high index of suspicion for GPA.
**Correct Answer:** B.