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: Pathology
Pauci immune glomerulonephritis is seen in aEUR' 
Select and explain. 
A. After transplant in alpos, B. Microscopic polyangiitis, C. Henoch-Schonlein nephritis, D. Lupus
B: Microscopic polyangiitis
Answer: B: Microscopic polyangiitis 
Explanation: Microscopic polyangitis fRef Bobbin's Th/e p. 976] Rapidly progressive glomerulonephritis may be caused by number of different diseases, some restricted to the kidneys and others systemic. Although no single mechanism can explain all cases, there is little doubt that in most cases, the glomerular injury is immunologically mediated. Thus a practical classification divides rapidly progressive glomerulonephritis into three groups on the basis of immunological findings. RAPIDLY PROGRESSIVE GLOMERULONEPHRITIS II Type RPGN Type I RPGN (anti GBM antibody) m (Immune (I complex) Type III RPGN (Pauci immune) * Idiopathic * Idiopathic * ANCA associated * Goodpasture * Post infectious * Idiopathic syndrome * Systemic lupus * Wegener erythematous granulomatosis * Henoch schnolein * Microscopic PAN purpura * Microscopic polyangitis