Which of the following is typically associated with normal complement levels in GN?

• A. Wegener's granulomatosis
• B. Churg-Strauss
• C. IgA nephropathy
• D. All of the above

Answer: (D)

Normal complement levels in glomerulonephritis usually point to diseases without significant immune complex–mediated consumption of complement. Wegener’s granulomatosis (granulomatosis with polyangiitis) and Churg-Strauss (eosinophilic granulomatosis with polyangiitis) are pauci-immune forms of GN, meaning there is little immune complex deposition in the glomeruli, so complements are typically not consumed and stay in the normal range. IgA nephropathy also commonly presents with normal serum complement levels despite IgA deposition in the mesangium; while complement can be involved, consumption is not a dominant feature in most cases. Because each of these conditions is typically associated with normal complement levels, the best overall answer is that all of the listed conditions fit this pattern.