Induction of corticosteroid resistance in vitro

Macrophage migration inhibitory factor (MIF) in bronchial asthma

BACKGROUND

Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine favouring the secretion of TNFalpha and IL-8 and counteracts anti-inflammatory effects of corticosteroids. Airways inflammation is a central feature of bronchial asthma and is characterized by the accumulation of eosinophils.

OBJECTIVE

The aim of this study was to investigate whether MIF is related to asthma symptoms and eosinophil accumulation in the airways.

METHODS

Serum MIF levels were measured by an enzyme-linked immunosorbent assay in 44 healthy subjects and 44 asthmatics. Levels of MIF in induced sputum were measured in 10 healthy subjects and 15 asthmatics. Levels of eosinophil cationic protein (ECP) in induced sputum were measured by a radioimmunosorbent assay. Fluorescence double immunostaining was conducted to examine cellular source and localization of MIF.

RESULTS

Serum MIF levels were significantly increased in asthmatic patients compared with age and sex-matched control subjects. Symptomatic patients had a higher MIF level than asymptomatic patients. Induced sputum obtained from asthmatics contained higher levels of MIF than those from control subjects. MIF levels in induced sputum were correlated with ECP levels in induced sputum. MIF was colocalized with eosinophil peroxidase staining in the cytoplasm of sputum cells.

CONCLUSION

Increased MIF levels are associated with asthma symptoms and one of the cellular sources of MIF in the airways are eosinophils.

Glucocorticoids inhibit proliferation and interleukin-4 and interleukin-5 secretion by aeroallergen-specific T-helper type 2 cell lines

BACKGROUND

Glucocorticoids play an important role in the treatment of allergic disease. The atopic process, itself, may reduce the response of peripheral blood mononuclear cells (PBMC) to these drugs.

OBJECTIVE

In this study we compared the effect of hydrocortisone (HC), beclomethasone (BDP), and mometasone (MF) on interleukin (IL)-4 and IL-5 secretion by aeroallergen-specific T-helper type 2 cells (Th2) and proliferation of PBMC from atopic donors.

METHODS

Cells were incubated with drug before stimulating with phytohemagglutinin and assessing proliferation (PBMC) and cytokine secretion (Th2).

RESULTS

The glucocorticoids concentration dependently inhibited proliferation and cytokine secretion, but had less effect on proliferation of cells from severe atopics than on cells from those whose symptoms required little treatment. The rank order of potency was MF (average IC50 0.01 nM) > BDP (4.0 nM) > HC (250 nM).

CONCLUSIONS

These experiments demonstrate glucocorticoid inhibition of IL-4 and IL-5 secretion by human Th2-like cells and proliferation of PBMC from severely and mildly allergic donors.