This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Marker for the renal vasculitis in children is 
Select and explain. 
A. Increased IgA level, B. Low complement level, C. | Antineutrophilic cytoplasmic antibody titre, D. Increase antinuclear antibody
A: Increased IgA level
Answer: A: Increased IgA level 
Explanation: Answer is A (Increased IgA levels): The most common systemic vasculitis in children is Henoch Schonlein Purpura, and the most common primary of glomerular disease is IgA Nephropathy. H.S purpura and IgA nephropathy may actually represent spectra of same disease and both are associated with elevated levels of IgA which is the single best answer of choice.