Bone marrow contribution to eosinophilic inflammation.
Allergen-induced bone marrow responses are observable in human allergic asthmatics, involving specific increases in eosinophil-basophil progenitors (Eo/B-CFU), measured either by hemopoietic assays or by flow cytometric analyses of CD34-positive, IL-3R alpha-positive, and/or IL-5-responsive cell populations. The results are consistent with the upregulation of an IL-5-sensitive population of progenitors in allergen-induced late phase asthmatic responses. Studies in vitro on the phenotype of developing eosinophils and basophils suggest that the early acquisition of IL-5R alpha, as well as the capacity to produce cytokines such as GM-CSF and IL-5, are features of the differentiation process. These observations are consistent with findings in animal models, indicating that allergen-induced increases in bone marrow progenitor formation depend on hemopoietic factor(s) released post-allergen. The possibility that there is constitutive marrow upregulation of eosinophilopoiesis in allergic airways disease is also an area for future investigation.
Department of Medicine, McMaster University, Hamilton, Ontario, Canada. denburg@fhs.mcmaster.ca
J A
JA
Denburg
L
L
Wood
G
G
Gauvreau
R
R
Sehmi
M D
MD
Inman
P M
PM
O'Byrne
D000485:Allergens; D000818:Animals; D001249:Asthma / Q000503:physiopathology*; D001491:Basophils; D001853:Bone Marrow / Q000502:physiology*; D004195:Disease Models, Animal; D004802:Eosinophilia / Q000503:physiopathology*; D004804:Eosinophils / Q000502:physiology*; D006410:Hematopoiesis / Q000276:immunology; D006801:Humans; D006969:Hypersensitivity, Immediate; D015848:Interleukin-5
D000485:Allergens; D015848:Interleukin-5