BACKGROUND AND OBJECTIVE: Asthma can be classified as eosinophilic or non-eosinophilic based on the cell profile of induced sputum. This classification can help determine whether corticosteroid treatment is indicated. We assessed the stability of these phenotypes over time and with different treatment regimens. METHODS: Clinically stable, non-smoking, asthmatic adults were enrolled in one of two studies. In study one, induced sputum cell counts from 28 subjects were analysed after 4 weeks without corticosteroid treatment and after 6 week treatments with placebo, regular inhaled beta-agonist, inhaled corticosteroid, and combined beta-agonist and corticosteroid. In study two, sputum from 26 subjects with non-eosinophilic asthma was analysed after 12 weeks of placebo and after four 2-week corticosteroid washouts. Sputum with <2% eosinophils was classified as non-eosinophilic. RESULTS: Sputum classification changed frequently in both studies. In study one, only one of eight participants with non-eosinophilic sputum after placebo treatment remained non-eosinophilic throughout. In study two, all of participants had at least one eosinophilic sputum sample, despite the fact that all had been non-eosinophilic at recruitment. Neutrophilic asthma was uncommon in both studies and was also inconsistent. CONCLUSIONS: The phenotypic classification of asthma changes frequently. A diagnosis of non-eosinophilic asthma should not be based on a single sputum sample.
BACKGROUND AND OBJECTIVE:Asthma can be classified as eosinophilic or non-eosinophilic based on the cell profile of induced sputum. This classification can help determine whether corticosteroid treatment is indicated. We assessed the stability of these phenotypes over time and with different treatment regimens. METHODS: Clinically stable, non-smoking, asthmatic adults were enrolled in one of two studies. In study one, induced sputum cell counts from 28 subjects were analysed after 4 weeks without corticosteroid treatment and after 6 week treatments with placebo, regular inhaled beta-agonist, inhaled corticosteroid, and combined beta-agonist and corticosteroid. In study two, sputum from 26 subjects with non-eosinophilic asthma was analysed after 12 weeks of placebo and after four 2-week corticosteroid washouts. Sputum with <2% eosinophils was classified as non-eosinophilic. RESULTS: Sputum classification changed frequently in both studies. In study one, only one of eight participants with non-eosinophilic sputum after placebo treatment remained non-eosinophilic throughout. In study two, all of participants had at least one eosinophilic sputum sample, despite the fact that all had been non-eosinophilic at recruitment. Neutrophilic asthma was uncommon in both studies and was also inconsistent. CONCLUSIONS: The phenotypic classification of asthma changes frequently. A diagnosis of non-eosinophilic asthma should not be based on a single sputum sample.
Authors: Wendy C Moore; Annette T Hastie; Xingnan Li; Huashi Li; William W Busse; Nizar N Jarjour; Sally E Wenzel; Stephen P Peters; Deborah A Meyers; Eugene R Bleecker Journal: J Allergy Clin Immunol Date: 2013-12-09 Impact factor: 10.793
Authors: Collin R Brooks; Christine J Van Dalen; Elizabeth Harding; Ian F Hermans; Jeroen Douwes Journal: BMC Pulm Med Date: 2017-12-04 Impact factor: 3.317
Authors: Lucy Pembrey; Mauricio L Barreto; Jeroen Douwes; Philip Cooper; John Henderson; Harriet Mpairwe; Cristina Ardura-Garcia; Martha Chico; Collin Brooks; Alvaro A Cruz; Alison M Elliott; Camila A Figueiredo; Sinéad M Langan; Beatrice Nassanga; Susan Ring; Laura Rodrigues; Neil Pearce Journal: ERJ Open Res Date: 2018-08-22