Neutropenic fever of unknown origin and disseminated granulomatous disease in a patient with acute lymphoblastic leukemia.

An 18-year-old male was admitted for his second induction chemotherapy treatment for an acute lymphoblastic leukaemia with cyclophosphamide, cytarabine, and mercaptopurine. He presented with high fever, abdominal pain, non-bloody diarrhoea, portal hypertension and leukopenia. Stool sample analysis, blood cultures and extensive work-up were negative. The only microbiologic evidence was the presence of cytomegalovirus DNA detected by PCR. A profound hypogammaglobulinemia was documented. Pathology material reported non-caseating granulomas in liver, bone marrow, duodenum and colon with negative cytomegalovirus immunostaining. What is your diagnosis?