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: Pharmacology
Siltuximab is used in treatment of ? 
Select and explain. 
A. Castlemans disease, B. Sezary syndrome, C. Ankylosing spondylitis, D. Non hodgkins lymphoma
A: Castlemans disease
Answer: A: Castlemans disease 
Explanation: Ans. is 'a' i.e., Castleman's diseaselRef: Multiple myeloma, an issue of hematology oncology clinics E boohKenneth C Anderson p. 9171Siltuximab (Anti IL-6):IL-6 is produced by the stromal cells of the bone marrow, and plays a crucial role in the proliferation and survival of multiple myeloma cells.