Biomarkers of airways inflammation in patients with severe asthma in a real clinical practice

Abstract

The aim of this study was to assess the biomarkers of eosinophilic airways inflammation in patients with severe asthma in a single secondary care center.

Methods: We examined 73 outpatients (32% male, aged 18-82 yr, mean age 55 yrs) with severe asthma (ERS/ATS 2014), among them 14% had orally streroid-dependent asthma. Patients did not receive any biologicals for ≥6 months. Blood eosinophils (Eos) were measured by automatic haemoanalyser and serum total IgE levels were assessed by immunofluorescence assay. FeNO was measured by a chemiluminescence analyzer (LR4000; UK). Eos≥150 cell/μl, IgE≥100 IU/ml and FeNO≥25 ppb were considered as elevated markers.

Results: In patients with severe asthma level of blood Eos was 392±53 cell/μl and 67% patients had Eos ≥150 cell/μl. FeNO was 33±4.3 ppb and 38% of patients had FeNO≥25 ppb. Concentration of IgE was 379±70 IU/ml and in 62% of patients level of IgE was ≥100 IU/ml. Eighty nine percent of patients had at least one or more elevated marker. Increased Eos were the single marker in 16% patients with severe asthma, IgE – in 12% (p>0.05) and FeNO – in 4% (p<0.05 compared with Eos). Two elevated markers (Eos≥150 cell/μl and IgE≥100 IU/ml) were diagnosed in 22%, Eos≥150 cell/μl and FeNO≥25 ppb - in 7% (p<0.05), FeNO≥25 ppb and IgE≥100 IU/ml - in 5% patients (p<0.01). All three elevated biomarkers were revealed in 22% of patients with severe asthma.

Conclusion: The majority of patients with severe asthma have at least one or more elevated biomarkers (blood Eos or IgE or FeNO) of eosinophilic airway inflammation. Blood eosinophils are increased most frequently. Many patients with severe asthma have an overlap of indications for prescription of biologicals.