High Transcriptional Activity and Clinical Correlations in Eosinophils of Patients with Late-Onset Asthma

BACKGROUND: The immunological features of eosinophils in early-onset asthma (EOA) differ from those in late-onset asthma (LOA).

Clinical trials of anti-interleukin-5 (IL-5) treatment for severe eosinophilic asthma showed a better response for LOA patients than EOA patients.

We wonder if the transcriptional activity of activated eosinophils was different in EOA and LOA.

METHODS: Eosinophils obtained from well-controlled EOA and LOA patients and normal subjects were compared in terms of the mRNA expression of activation-related genes and specific markers related to cell functions in eosinophils activated by IL-5 or IL-17.

The correlation between mRNA expression and clinical features and lung function was further analyzed.

RESULTS: The transcriptional expression of most genes was higher in activated eosinophils from LOA patients than in those from EOA patients and normal subjects.

After IL-17 stimulation, the expression of certain genes was higher in atopic EOA patients than in non-atopic EOA patients.

Similar observation was noted in obese EOA patients.

After IL-5 stimulation, the transcriptional expression of most genes in eosinophils from LOA patients was negatively correlated with indicators of lung function.

These correlations were less pronounced in EOA patients: After IL-17 stimulation, some genes in EOA patients were negatively correlated with post-bronchodilator changes in lung function.

CONCLUSION: This study describes differences in the transcriptional active patterns of eosinophils and their correlation to atopy and obesity by age of onset.

High transcriptional activity in activated eosinophils and a negative correlation to lung function indicate the importance of eosinophils in the pathogenesis of LOA.