Study Objective: to track the laboratory dynamics in children with mild persistent bronchial asthma (BA) at various stages of disease with or without baseline therapy.
Study Design: prospective cohort study.
Materials and Methods. The study included 42 patients with mild persistent BA aged 5 to 16 years. Each child was followed up for 3 years. At initiation of the study and during each visit, all patients had their blood eosinophils, nasal discharge (ND) and induced sputum (IS), as well as serum eosinophil cation protein (ECP) tested; and their respiratory function was assessed. All children were prescribed baseline therapy with low doses of inhalative glucocorticosteroids (GCS); 18 children also received allergen-specific immunotherapy (ASIT).
Study Results. Inhalative GCS for BA exacerbations facilitated normalisation of sputum, ND and blood eosinophils. During periods of BA remission, ND and IS eosinophil levels increased, but patients did not have rhinitis and BA symptoms. Eosinophil levels in IS were higher vs. BA control (р = 0.05) and lower vs. disease exacerbations (р < 0.05). We did not find any differences in laboratory results in children with or without ASIT who were treated with low doses of inhalative and nasal GCS.
Conclusion. Eosinophile inflammatory phenotype in patients did not charge depending on disease duration and control therapies. According to the study data, eosinophile levels in IS, when BA exacerbation was recorded, were 8.0% [3.0–16.0%]. This value can be used as an additional predictor for the need in increased therapy (a step forward). Irrespective of the disease stage and therapy, there was correlation between blood eosinophile level and IS eosinophile level and between IS eosinophile level and blood ECP concentration.
Contributions: Fedorov, I.A. — study design and planning; approval of the manuscript for publication; Rybakova, O.G. — patient examination, raw materials collection for manuscript, information analysis, statistical data processing, manuscript preparation.
Conflict of interest: The authors declare that they do not have any conflict of interests.
I.A. Fedorov (Corresponding author) — South Ural State Medical University of the Ministry of Health of the Russian Federation; 64 Vorovsky Str., Chelyabinsk, Russian Federation 454092. eLIBRARY.RU SPIN: 4305-6948. E-mail: firstname.lastname@example.org
O.G. Rybakova — South Ural State Medical University of the Ministry of Health of the Russian Federation; 64 Vorovsky Str., Chelyabinsk, Russian Federation 454092. eLIBRARY.RU SPIN: 1334-6396. E-mail: email@example.com