This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunomodulator, Subject name: Pharmacology
DENOSUMAB a monoclonal antibody against RANKL receptor is used in the treatment of 
Select and explain. 
A. Rheumatoid arthritis, B. Osteoporosis, C. Osteoarthritis, D. SLE
B: Osteoporosis
Answer: B: Osteoporosis 
Explanation: Ans. is 'b' i.e. Osteoporosis Osteoclast is a cell responsible for bone resorption.Osteoclasts express RANK receptors on its surface (RANK receptor activator for nuclear factor)When RANK receptor combine with their ligands (RANKL), osteoclastogenesis is a initiated and bone resorption occurs.Denosumab is a fully humanized monoclonal antibody against RANK ligand.It prevents the activation of the osteoclasts by these ligand.Note:Osteoporosis is a disease characterized by decrease in the bone massIn osteoporosis there is increase in the osteoclast activity and there is increased expression of RANK and RANKL.