Expression of FcgammaRIII (CD16) on human peripheral blood eosinophils increases in allergic conditions.
BACKGROUND
Blood eosinophils have mRNA for FcgammaRIIIB (CD16) but no or minimal spontaneous CD16 expression. Because IFN-gamma and chemotactic factors induce eosinophil CD16 expression in vitro, we postulated that blood eosinophils could express CD16.


OBJECTIVE
Blood of nonallergic controls and subjects with allergic rhinitis, allergic and nonallergic asthma, or hypereosinophilia of various etiologies were analyzed for leukocyte CD16 surface expression.


METHODS
CD16(+) eosinophils were identified on the basis of physico-optic characteristics, major basic protein, CD49b expression, and sorting by flow cytometry and microscope examination.


RESULTS
Subjects with allergic rhinitis and subjects with asthma had higher median percentages of CD16(+) eosinophils (8.1% [1% to 48.6%] and 7.3% [1.4% to 31.1%], respectively) than nonallergic controls and nonallergic asthmatics (3% [0% to 11%] and 4.6% [2.9% to 5.1%], respectively). In subjects with hypereosinophilia, CD16(+) eosinophils were increased only in a case of drug allergy. When subjects with mild allergic asthma were challenged with a relevant aeroallergen, blood CD16(+) eosinophils further increased during or after the late-phase response (6 to 48 hours after challenge; mean +/- SEM, 9.4% +/- 2.5% to 20.0% +/- 3.0%). CD16(+) eosinophils expressed more IL-5 receptor but less CD11b and IL-12p35 than did CD16(-) eosinophils.


CONCLUSIONS
Upregulation of blood CD16(+) eosinophils in allergic conditions and its association with a modified phenotype suggest that CD16 receptor could play a role in eosinophil activation in allergy.
Davoine
Francis
F
Unité de recherche en pneumologie, Centre de recherche de l'Hôpital Laval, Institut universitaire de cardiologie et de pneumologie de l'Université Laval, Sainte-Foy, Québec, Canada.
Lavigne
Sophie
S
Chakir
Jamila
J
Ferland
Claudine
C
Boulay
Marie-Eve
ME
Laviolette
Michel
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000485:Allergens / Q000008:administration & dosage / Q000276:immunology; D001249:Asthma / Q000276:immunology* / Q000503:physiopathology; D004802:Eosinophilia / Q000276:immunology; D004804:Eosinophils / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000276:immunology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D017452:Receptors, IgG / Q000378:metabolism*; D012221:Rhinitis, Allergic, Perennial / Q000276:immunology* / Q000503:physiopathology
D000485:Allergens; D017452:Receptors, IgG