<prompt> Late onset hemorrhagic cystitis after bone marrow transplanatation is caused by:CyclophosphamideIfosfamideAdeno virusCytomegalo virus  <response>: After bone marrow transplantation BMT, early-onset hemorrhagic cystitis is related to drugs in the treatment regimen e.g., cyclophosphamide, ifosfamide, and late-onset hemorrhagic cystitis is usually due to the polyoma virus BKV or adenovirus type 11. Ref: Harrisons principles of internal medicine, 18th edition, Page: 2275. 