Researchers have uncovered a potentially new treatment approach forsevere asthma, by blocking a powerful immune system chemical, presentin large amounts in patients with the severe form of the disease, asmall study in Thorax reveals.
Around one in 10 asthmatics has the severe form of the disease,which frequently requires progressively higher doses of steroids in abid to control symptoms.
Severe asthma is also associated with a much higher risk of illness anddeath than milder forms and accounts for almost a third of healthservice costs for asthma
The research team investigated tumour necrosis factor alpha (TNFalpha), which is found in a range of chronic inflammatory conditions,including rheumatoid arthritis, Crohn's disease, and psoriasis.
Included in the study were 26 healthy people, 67 mild asthmatics, and 51 severe asthmatics.Bronchial fluid and lung tissue samples were taken from the participants to discover their levels of TNF alpha.
Levels were significantly higher in those with severe disease and concentrated in one particular type of immune cell(mast cells) which are recognised components of the inflammatory reaction in asthma.
TNF alpha levels were low and similar in those with no asthma or who only had mild symptoms.
This suggests that the high levels of TNF alpha in severe disease arecharacteristic of more chronic disease that is resistant to steroidtreatment, rather than a feature of the disease itself, say theauthors.
Seventeen people with severe asthma who still had symptoms, despitebeing treated with a range of drugs, were also given 25 mg of a drugthat blocks TNF alpha production (etanercept) twice weekly, injectedbelow the skin for 12 weeks. Fifteen completed the course.
At the end of the study period, these patients experienced asignificant improvement in symptoms and lung function. Two patientswere able to discontinue one of their drugs.
The treatment also curbed the inflammatory reaction in the lungs, knownas bronchial hyperresponsiveness. And there were few side effects.
The authors caution that further research will be required before thisapproach can be recommended, but they say that it offers a potentiallynew avenue of treatment for severe asthma.
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