An absolute neutrophil count (ANC) chronically less than 500/mm3, usually less than 200/mm3, is the main sign of Kostmann's. Other elements include the<unk> ty of<unk> , the chronology (from birth; not emerging later), and other normal findings (hemoglobin, platelets, general body health). Isolated<unk>  in infants can occur in viral infections, autoimmune<unk>  of infancy, bone marrow suppression from a drug or toxin, hypersplenism, and passive placental transfer of maternal IgG. A bone marrow test can assist in diagnosis. The bone marrow usually shows early granulocyte precursors, but myelopoietic development stops ("arrests") at the promyelocyte and/or myelocyte stage, so that few maturing forms are seen. Neutrophil survival is normal.
Severe congenital neutropenia
Autoimmune neutropenia
Bare lymphocyte syndrome
Diffuse infiltrative lymphocytosis syndrome
Adult-onset immunodeficiency syndrome
Refractory cytopenia of childhood
Leukocyte adhesion deficiency
Myelodysplastic syndrome