title: Severe combined immunodeficiency (SCID) associated neutropenia: a lesson from monozygotic twins.
abstract: A case of severe combined immunodeficiency (SCID) in monozygotic twin sisters was detected at 3 months of age with neutropenia in one twin and a normal differential count in the other. The neutropenic twin, suffering from severe skin ulcers, was successfully treated with granulocyte colony stimulating factor (G-CSF). Discordant occurrence of neutropenia in identical twins shows that there may be a non-genetic cause for the neutropenia in SCID. Suppression of myelopoiesis was probably induced by activated maternal T cells. The neutropenia in this case may thus be classified as SCID associated neutropenia, as opposed to reticular dysgenesis, in which the neutropenia is G-CSF refractory and is most probably caused by a genetic stem cell defect. A response to G-CSF in a neutropenic child with SCID can be clinically beneficial and might help to distinguish between G-CSF unresponsive reticular dysgenesis and G-CSF responsive SCID associated neutropenia.
authors.affiliation: Department of Paediatrics, University of Düsseldorf, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Niehues
authors.forename: K
authors.initials: K
authors.lastname: Schwarz
authors.forename: M
authors.initials: M
authors.lastname: Schneider
authors.forename: H
authors.initials: H
authors.lastname: Schroten
authors.forename: E
authors.initials: E
authors.lastname: Schröder
authors.forename: V
authors.initials: V
authors.lastname: Stephan
authors.forename: V
authors.initials: V
authors.lastname: Wahn
mesh_terms: D004200:Diseases in Twins; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000627:therapeutic use; D006801:Humans; D007223:Infant; D009503:Neutropenia / Q000209:etiology* / Q000628:therapy; D016511:Severe Combined Immunodeficiency / Q000150:complications*; D014430:Twins, Monozygotic
chemical_list: D016179:Granulocyte Colony-Stimulating Factor