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Updated: Mar 12, 2026

Bronchial Thermoplasty: A Novel Therapeutic Approach to Severe Asthma
Published on: November 4, 2010
Mepolizumab in the management of severe eosinophilic asthma in adults: current evidence and practical experience
Gilda Varricchi1, Diego Bagnasco2, Matteo Ferrando2
1Department of Translational Medical Sciences, Division of Clinical Immunology and Allergy, University of Naples Federico II, Naples, Italy.
Eosinophils represent approximately 1% of peripheral blood leukocytes in normal donors and their maturation and differentiation in the bone marrow are mainly regulated by interleukin (IL)-5 [Broughton et al. 2015]. IL-5, a cytokine that belongs to the β common-chain family, together with IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF), stimulates also the activation and survival of eosinophils and, to some extent, of basophils. IL-5 binds to a heterodimer receptor composed of the specific subunit IL-5Rα and a common subunit βc shared with IL-3 and GM-CSF. Human eosinophils express approximately a three-fold higher level of IL-5Rα compared with basophils. Major sources of IL-5 are T-helper 2 (Th2) cells, mast cells, CD34+ progenitor cells, invariant natural killer (NK) T-cells, group 2 innate lymphoid cells (ILC2s), and eosinophils themselves. ILC2s control not only eosinophil number but also their circadian cycling through the production of IL-5.
Eosinophils represent approximately 1% of peripheral blood leukocytes in normal donors and their maturation and differentiation in the bone marrow are mainly regulated by interleukin (IL)-5 [Broughton et al. 2015]. IL-5, a cytokine that belongs to the β common-chain family, together with IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF), stimulates also the activation and survival of eosinophils and, to some extent, of basophils. IL-5 binds to a heterodimer receptor composed of the specific subunit IL-5Rα and a common subunit βc shared with IL-3 and GM-CSF. Human eosinophils express approximately a three-fold higher level of IL-5Rα compared with basophils. Major sources of IL-5 are T-helper 2 (Th2) cells, mast cells, CD34+ progenitor cells, invariant natural killer (NK) T-cells, group 2 innate lymphoid cells (ILC2s), and eosinophils themselves. ILC2s control not only eosinophil number but also their circadian cycling through the production of IL-5.
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