This program will give an update on congenital and acquired neutropenia. The first session will focus on neutropenia associated with newer cancer treatments such as anti-CD20 and other antibodies, with presentation of new insights into pathogenesis (including the role of cytokines and mannose-binding proteins), evolving pathogen and resistance patterns, and strategies for prevention and treatment. In the subsequent talks, the speakers will address current knowledge about the molecular basis of congenital neutropenia syndromes and the use of granulocyte colony-stimulating factor (GCSF) in these syndromes, including data on transformation to myelodysplasia and acute myelogenous leukemia. The discussion should aid the clinician in understanding the short and long-term risks and benefits of G-CSF therapy in congenital neutropenias.