Kinetics of IL-10 production after segmental antigen challenge of atopic asthmatic subjects.
BACKGROUND
IL-10 is an anti-inflammatory cytokine made by lymphocytes, monocytes-macrophages, and eosinophils, and it may have an important role in regulating the asthmatic inflammatory response. IL-10 levels have been reported to be reduced in asthmatic airways, potentially contributing to more intense inflammation.


OBJECTIVE
We sought to determine whether IL-10 levels were deficient in patients with mild asthma compared with controls and to determine whether IL-10 levels were associated with the resolution of eosinophilic inflammation.


METHODS
We quantified IL-10 levels in the bronchoalveolar lavage (BAL) fluid (ELISA), BAL cells (quantitative immunocytochemistry), purified alveolar macrophages-monocytes studied ex vivo (ELISA), before (day 1) and after (24 hours [day 2], 1 week [day 9], and 2 weeks [day 16]) segmental antigen challenge (SAC), and investigated the effect of glucocorticoid treatment on ex vivo macrophage-monocyte IL-10 production.


RESULTS
IL-10 levels were significantly higher in the BAL fluid of mild asthmatic subjects who demonstrated a dual reaction (both early and late) after whole lung ragweed inhalation challenge compared with nonallergic, nonasthmatic control subjects before and 24 hours and 1 week after SAC. Macro-phages-monocytes obtained before and after SAC from asthmatic patients also secreted increased amounts of IL-10 ex vivo than those from controls. Dexamethasone did not significantly change spontaneous IL-10 secretion from macrophages-monocytes in vitro. Quantitative immunocytochemical analysis of BAL cells demonstrated increased IL-10 in macrophages 24 hours after SAC and a similar trend in eosinophils.


CONCLUSIONS
IL-10 is not deficient in mild asthma. Furthermore, BAL IL-10 levels are significantly higher in asthmatic subjects with a dual response than in control subjects before and after SAC. The increase in IL-10 was coincident with the initial increase in BAL eosinophils, although BAL eosinophilia persisted after IL-10 levels had returned to baseline, suggesting that the increased IL-10 levels could not promptly terminate this localized eosinophilic response.
Colavita
A M
AM
Division of Critical Care, Pulmonary, Allergic, and Immunologic Diseases, Department of Medicine, Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA 19107-5083, USA.
Hastie
A T
AT
Musani
A I
AI
Pascual
R M
RM
Reinach
A J
AJ
Lustine
H T
HT
Galati
S A
SA
Zangrilli
J G
JG
Fish
J E
JE
Peters
S P
SP
D000485:Allergens / Q000276:immunology*; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D052179:Antigens, Plant; D001249:Asthma / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology; D004804:Eosinophils / Q000166:cytology / Q000276:immunology; D005938:Glucocorticoids / Q000494:pharmacology; D006801:Humans; D016753:Interleukin-10 / Q000096:biosynthesis*; D007700:Kinetics; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D010940:Plant Proteins / Q000276:immunology*; D006109:Poaceae / Q000276:immunology; D011058:Pollen / Q000276:immunology*
D000485:Allergens; C026967:Amb a I protein, Ambrosia artemisiifolia; D000893:Anti-Inflammatory Agents; D052179:Antigens, Plant; D005938:Glucocorticoids; D010940:Plant Proteins; D016753:Interleukin-10; D003907:Dexamethasone