Immunohistochemical detection of human basophils in late-phase skin reactions.
BACKGROUND
Human basophils are difficult to detect with classic histochemical stains at sites of allergic inflammation. The 2D7 anti-basophil monoclonal antibody was used to identify basophils in skin during the late-phase response to a cutaneous allergen challenge.


METHODS
The 2D7 monoclonal antibody was used on protease-digested sections of skin biopsy specimens obtained 6 and 24 hours after an allergen or buffer challenge. The skin chamber technique was used to compare buffer- and allergen-challenged sites at 6 hours, and intradermal injection of allergen was used to compare allergen-challenged sites at 6 and 24 hours.


RESULTS
Dramatic increases in the numbers of 2D7+ cells and in tissue staining by 2D7 were observed 6 hours after allergen challenge compared with buffer challenge. Histamine levels in skin chamber fluid varied with 2D7+ cell concentrations. By 24 hours, 2D7+ cells and tissue staining appeared to diminish but were still detectable in the allergen-challenged sites. Basophils localized primarily in and around blood vessels, whereas mast cells remained mostly in the superficial dermis. Mast cells were 2D7- in both the allergen- and buffer-challenged skin. Metachromatic staining of 2D7+ basophils with toluidine blue was absent in these tissue sections.


CONCLUSIONS
The 2D7 monoclonal antibody provides a more sensitive and precise marker than histochemical staining for human basophil involvement during the late-phase response to an allergen challenge. Basophil infiltration was observed at 6 hours only after allergen challenge and persisted at similar levels by 24 hours.
Irani
A M
AM
Department of Pediatrics, Virginia Commonwealth University, Richmond 23298, USA.
Huang
C
C
Xia
H Z
HZ
Kepley
C
C
Nafie
A
A
Fouda
E D
ED
Craig
S
S
Zweiman
B
B
Schwartz
L B
LB
D000485:Allergens / Q000276:immunology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001491:Basophils / Q000276:immunology* / Q000378:metabolism; D001706:Biopsy; D001808:Blood Vessels / Q000276:immunology; D003876:Dermatitis, Atopic / Q000276:immunology* / Q000378:metabolism; D010450:Endopeptidases / Q000276:immunology / Q000494:pharmacology; D006632:Histamine / Q000032:analysis / Q000378:metabolism; D006651:Histocytochemistry; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008407:Mast Cells / Q000276:immunology; D051379:Mice; D006109:Poaceae / Q000276:immunology; D011058:Pollen / Q000276:immunology; D012867:Skin / Q000276:immunology* / Q000378:metabolism; D012882:Skin Tests
D000485:Allergens; D000911:Antibodies, Monoclonal; D006632:Histamine; D010450:Endopeptidases