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: Pediatrics
A neonate with recurrent infection was diagnosed with Kostmann syndrome. Treatment is: 
Select and explain. 
A. G-CSF and HSCT, B. GM-CSF, C. Antithymocyte globulin+cyclosporine, D. Antithymocyte globulin+cyclosporine +GM-CSF
A: G-CSF and HSCT
Answer: A: G-CSF and HSCT 
Explanation: Severe congenital neutropenia (SCN) consists of a group of inherited diseases that are characterized by severely impaired neutrophil counts [ Diagnosis of SCN requires examination of the bone marrow. Subcutaneous injection of the cytokine granulocyte colony-stimulating factor (G-CSF) usually improves neutrophil development and thus prevents infection in most SCN diseases. SCN with ELA2 mutation are refractory to G-CSF and may require curative treatment allogeneic hematopoietic stem cell transplantation (HSCT). Ref: Dale D.C. (2010). Chapter 65. Neutropenia and Neutrophilia. In J.T. Prchal, K. Kaushansky, M.A. Lichtman, T.J. Kipps, U. Seligsohn (Eds), Williams Hematology, 8e.