Airway remodeling and inflammation in symptomatic infants with reversible airflow obstruction.
BACKGROUND
We hypothesized that the epithelial reticular basement membrane (RBM) thickening and eosinophilic inflammation characteristic of asthma would be present in symptomatic infants with reversible airflow obstruction.


METHODS
RBM thickness and numbers of inflammatory cells were determined in ultrathin sections of endobronchial biopsies obtained from 53 infants during clinical bronchoscopy for severe wheeze and/or cough. Group A: 16 infants with a median age of 12 months (range 3.4-26 months), with decreased specific airway conductance (sGaw) and bronchodilator reversibility; Group B: 22 infants with a median age of 12.4 months (5.1-25.9 months), with decreased sGaw but without bronchodilator reversibility; and Group C: 15 infants with a median age of 11.5 months (3.4-24.3 months) with normal sGaw. Additional comparisons were made with the following groups. Group D: 17 children, median age 10.3 years (6-16 years), with difficult asthma; Group E: 10 pediatric control subjects without asthma, median age 10 years (6-16 years); and Group F: nine adult normal, healthy control subjects, median age 27 years (21-42 years).


RESULTS
There were no significant differences in RBM thickness or inflammatory cell number between the infant groups. RBM thickness was similar in the infants and Groups E and F. However, the RBM in all infant groups (Group A: median 4.3 microm [range 2.8-9.2 microm]; Group B: median 4.15 microm [range 2.7-5.8 microm]; Group C: median 3.8 microm [range 2.7-5.5 microm]) was significantly less thick than that in the older children with asthma (Group D: median 8.3 microm [range 5.3-12.7 microm]; p < 0.001).


CONCLUSIONS
RBM thickening and the eosinophilic inflammation characteristic of asthma in older children and adults are not present in symptomatic infants with reversible airflow obstruction, even in the presence of atopy.
Saglani
Sejal
S
Lung Pathology, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.
Malmström
Kristiina
K
Pelkonen
Anna S
AS
Malmberg
L Pekka
LP
Lindahl
Harry
H
Kajosaari
Merja
M
Turpeinen
Markku
M
Rogers
Andrew V
AV
Payne
Donald N
DN
Bush
Andrew
A
Haahtela
Tari
T
Mäkelä
Mika J
MJ
Jeffery
Peter K
PK
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000402:Airway Obstruction / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology*; D001485:Basement Membrane / Q000473:pathology; D001707:Biopsy, Needle; D016535:Bronchial Hyperreactivity / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology; D001999:Bronchoscopy; D016022:Case-Control Studies; D002675:Child, Preschool; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007249:Inflammation / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D011336:Probability; D011379:Prognosis; D018570:Risk Assessment; D012737:Sex Factors
D018927:Anti-Asthmatic Agents