Analysis of the lineage relationship between mast cells and basophils using the c-kit D816V mutation as a biologic signature.
BACKGROUND
Mast cells and basophils share similar morphologic and functional properties; however, it is not known whether they are derived from a bilineage (basophil/mast cell)-restricted progenitor.


OBJECTIVE
To assess whether basophils and mast cells are derived from common committed progenitors using the c-kit D816V mutation as a biologic signature.


METHODS
The D816V c-kit mutation found in mast cells of patients with systemic mastocytosis is used as a trackable genetic marker to assess the lineage relationship between mast cells and basophils. Blood and bone marrow aspirates were collected from 33 consecutive patients with mastocytosis with different disease severity. Peripheral blood basophils, monocytes and neutrophils were sorted by immunomagnetic beads. Presence of the D816V c-kit mutation was analyzed by restriction fragment length polymorphism in the genomic DNA and mRNA from sorted cells in all patients and in the genomic DNA of individual basophils of 1 patient.


RESULTS
The c-kit D816V mutation was detectable in basophils of 5 patients (15%). All 5 patients had the c-kit mutation also detectable in monocytes and thus had multilineage involvement. Single cell analysis of the genomic DNA in 1 patient showed a similar degree of clonal expansion in basophils, monocytes, and neutrophils. Mutated c-kit was expressed at the mRNA level in all 5 patients. There was no difference in surface Kit expression levels in basophils.


CONCLUSIONS
Basophils carrying the D816V c-kit mutation in mastocytosis were detected only in the context of a multilineage involvement. These results argue against the presence of a bilineage-restricted committed progenitor for mast cells and basophils.
Kocabas
Can N
CN
Laboratory of Allergic Diseases, National Institute of Allergy and Infectious Diseases/NIH, Bethesda, MD 20892, USA.
Yavuz
Akif S
AS
Lipsky
Peter E
PE
Metcalfe
Dean D
DD
Akin
Cem
C
D001491:Basophils / Q000276:immunology / Q000378:metabolism*; D019070:Cell Lineage / Q000235:genetics*; D006801:Humans; D008407:Mast Cells / Q000276:immunology / Q000378:metabolism*; D008415:Mastocytosis / Q000097:blood / Q000235:genetics* / Q000276:immunology; D009154:Mutation; D012150:Polymorphism, Restriction Fragment Length; D019089:Stem Cell Factor / Q000032:analysis / Q000235:genetics* / Q000378:metabolism
D019089:Stem Cell Factor