Continuous exposure to house dust mite elicits chronic airway inflammation and structural remodeling.
It is now fully appreciated that asthma is a disease of a chronic nature resulting from intermittent or continued aeroallergen exposure leading to airway inflammation. To investigate responses to continuous antigen exposure, mice were exposed to either house dust mite extract (HDM) or ovalbumin intranasally for five consecutive days, followed by 2 days of rest, for up to seven consecutive weeks. Continuous exposure to HDM, unlike ovalbumin, elicited severe and persistent eosinophilic airway inflammation. Flow cytometric analysis demonstrated an accumulation of CD4+ lymphocytes in the lung with elevated expression of inducible costimulator a marker of T cell activation, and of T1/ST2, a marker of helper T Type 2 effector cells. We also detected increased and sustained production of helper T cell Type 2-associated cytokines by splenocytes of HDM-exposed mice on in vitro HDM recall. Histologic analysis of the lung showed evidence of airway remodeling in mice exposed to HDM, with goblet cell hyperplasia, collagen deposition, and peribronchial accumulation of contractile tissue. In addition, HDM-exposed mice demonstrated severe airway hyperreactivity to methacholine. Finally, these responses were studied for up to 9 weeks after cessation of HDM exposure. We observed that whereas airway inflammation resolved fully, the remodeling changes did not resolve and airway hyperreactivity resolved only partly.
Department of Pathology and Molecular Medicine, Center for Gene Therapeutics, Millennium Pharmaceuticals, Cambridge, Massachusetts, USA.
Jill R
JR
Johnson
Ryan E
RE
Wiley
Ramzi
R
Fattouh
Filip K
FK
Swirski
Beata U
BU
Gajewska
Anthony J
AJ
Coyle
José-Carlos
JC
Gutierrez-Ramos
Russ
R
Ellis
Mark D
MD
Inman
Manel
M
Jordana
D000403:Airway Resistance; D000485:Allergens / Q000009:adverse effects*; D000818:Animals; D001249:Asthma / Q000276:immunology* / Q000473:pathology; D001707:Biopsy, Needle; D016535:Bronchial Hyperreactivity / Q000276:immunology* / Q000473:pathology; D002908:Chronic Disease; D016207:Cytokines / Q000032:analysis; D004195:Disease Models, Animal; D004391:Dust; D005260:Female; D007136:Immunoglobulins / Q000032:analysis; D007150:Immunohistochemistry; D007249:Inflammation / Q000503:physiopathology*; D018836:Inflammation Mediators / Q000032:analysis*; D051379:Mice; D008807:Mice, Inbred BALB C; D008925:Mites; D011336:Probability; D011657:Pulmonary Eosinophilia / Q000276:immunology / Q000503:physiopathology; D012680:Sensitivity and Specificity
D000485:Allergens; D016207:Cytokines; D004391:Dust; D007136:Immunoglobulins; D018836:Inflammation Mediators