This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urinary tract, Subject name: Pathology
Crescent are derived from which of the following 
Select and explain. 
A. Epithelial cells+fibrin+macrophage, B. Mesangial cell+fibrin+macrophage, C. Tubular cell+mesangialcell+fibtrin, D. Neutrophil +tubular cell +fibrin
A: Epithelial cells+fibrin+macrophage
Answer: A: Epithelial cells+fibrin+macrophage 
Explanation: Refer Robbins page no Pg 921dahe glomeruli are large and hypercellular. The hypercellu- larity is produced both by proliferation of cells in the mesangium and so-called endocapillary proliferation involving capillary endothelium and infiltrating leukocytes. The glomeruli have an accentuated "lobular" appearance due to the proliferating mesangial cells and increased mesangial matrix (Fig. 20-16). The GBM is thickened, and often shows a "double- contour" or "tram-track" appearance, especially evident in silver or PAS stains. This is caused by "duplication" of the basement membrane (also commonly referred to as splitting), usually as the result of new basement membrane synthesis in response to subendothelial deposits of immune complexes. Between the duplicated basement membranes there is inclu- sion or interposition of cellular elements, which can be of mesangial, endothelial, or leukocytic origin. Such interposition also gives rise to the appearance of "split" basement mem- branes (Fig. 20-17A). Crescents are present in many cases