Neutrophilic inflammation as a possible explanation for a reduced treatment response in obese patients with asthma

Increased number of neutrophils are present in the airways during the late-phase reaction after allergen challenge, in fatal or nocturnal asthma, and in severe asthma.

The incidence of asthma and obesity is increasing worldwide, and reports suggest that obese patients may have more severe asthma or reduced response to therapy. This study from the Netherlands included data from four asthma cohorts.

At baseline, FEV(1)  and bronchial hyperresponsiveness were comparable in 63 obese (BMI equal or more than 30 kg/m(2) ) and 213 lean patients (BMI  lower than 25 kg/m(2) ).

After a two-week treatment with corticosteroids, there was less corticosteroid-induced improvement in FEV(1) in obese patients (median 1.7% vs 6.3% respectively, P = 0.04). The percentage of sputum eosinophils improved significantly less with higher BMI.

The smaller improvement in FEV(1) and sputum eosinophils suggests a worse corticosteroid treatment response in obese asthmatics.

Editor’s note: Previous studies of anti-IL-5 agents showed benefit only in some asthmatic patients with predominantly eosinophilic inflammation. As a future research avenue, it would be interesting to see if localized anti-neutrophilic therapies can bring improvement in obese patients with asthma.

Question & Answer

In patients with asthma and chronic productive cough, polymorphonuclear (PMN) neutrophil leukocytes in sputum suggest:

(A) infection
(B) GERD
(C) presence of a foreign body
(D) exercise-induced asthma
(E) extrinsic asthma

Correct answers: A, B, C

References:

Obesity in asthma: more neutrophilic inflammation as a possible explanation for a reduced treatment response. Telenga ED, Tideman SW, Kerstjens HA, Hacken NH, Timens W, Postma DS, van den Berge M. Allergy. 2012 Aug;67(8):1060-8. doi: 10.1111/j.1398-9995.2012.02855.x. Epub 2012 Jun 12.

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