Which type of ANCA is typically positive in Wegener's granulomatosis?

In Wegener's granulomatosis, now known as granulomatosis with polyangiitis (GPA), the type of ANCA (anti-neutrophil cytoplasmic antibody) that is typically positive is C-ANCA, which stands for cytoplasmic ANCA. This specific antibody is primarily directed against proteinase 3 (PR3), an enzyme found in neutrophils.

The presence of C-ANCA in patients with GPA correlates strongly with the disease and can serve as a useful marker for diagnosis and monitoring disease activity. The immune response related to this condition often results in small- to medium-sized vessel vasculitis, which can affect multiple organ systems including the lungs, kidneys, and sinuses.

While P-ANCA (perinuclear ANCA) is associated with other types of vasculitis, such as microscopic polyangiitis and Churg-Strauss syndrome, it is not typically prevalent in patients with Wegener's granulomatosis. This distinction is clinically significant, as the presence of C-ANCA can aid healthcare providers in making a more accurate diagnosis and determining appropriate treatment strategies for affected individuals.