Bronchial eosinophils, neutrophils, and CD8 + T cells influence asthma control and lung function in schoolchildren and adolescents with severe treatment-resistant asthma

• Published in: Respiratory Research 2022, Vol.23 (1)
• Main Authors: Eller, Miriam Cardoso Neves, Pierantozzi Vergani, Karina, Saraiva-Romanholo, Beatriz Mangueira, de Souza Xavier Costa, Natália, de Brito, Jôse Mára, Antonangelo, Leila, Faria, Caroline Silvério, Rodrigues, Joaquim Carlos, Mauad, Thais
• Format: Report
• Language: English
• Subjects: Asthma in children; Care and treatment; Health aspects; Patient outcomes; T cells
• ISSN: 1465-9921
• DOI: 10.1186/s12931-022-02259-4

Studies in adult severe treatment-resistant asthma (STRA) have demonstrated heterogeneous pathophysiology. Studies in the pediatric age group are still scarce, and few include bronchial tissue analysis. We investigated 6-18-year-old patients diagnosed with STRA in Sao Paulo, Brazil, by characterizing the different lung compartments and their correlations with asthma control and lung function. Inflammatory profiles of 13 patients with a confirmed diagnosis of STRA were analyzed using blood, induced sputum, bronchoalveolar lavage, viral and bacterial screens and endobronchial biopsy. Inflammatory cells, cytokines, and basement membrane thickening were tested for correlations with the asthma control test (ACT) and spirometry and plethysmography parameters. Endobronchial biopsy specimens from 11 patients were viable for analysis. All biopsies showed eosinophilic infiltration. Submucosal (SM) eosinophils and neutrophils were correlated with worse lung function (pre-BD FEV1), and SM neutrophils were correlated with fixed obstruction (post-BD FEV1). Intraepithelial (IE) neutrophils were positively correlated with lung function (pre-BD sGaw). CD8 + T cells had the highest density in the IE and SM layers and were positively correlated with ACT and negatively correlated with the cytokines IL1[beta], IL2, IL5, IL7, IL10, IL12, IL17, GCSF, MCP-1, INF-[delta], and TNF[alpha] in sputum supernatant. The ASM chymase + mast cell density correlated positively with quality-of-life score (pAQLQ) and ACT. Eosinophils and SM neutrophils correlated with worse lung function, while IE neutrophils correlated with better lung function. Most importantly, CD8 + T cells were abundant in bronchial biopsies of STRA patients and showed protective associations, as did chymase + mast cells.