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Background: Neutrophilic asthma (NA) is a clinically important asthma phenotype, the cellular and molecular basis of which is not completely understood. Airway macrophages are long‐lived immune cells that exert important homeostatic and inflammatory functions which are dysregulated in asthma. Unique transcriptomic programmes reflect varied macrophage phenotypes in vitro. We aimed to determine whether airway macrophages are transcriptomically altered in NA. Methods: We performed RNASeq analysis on flow cytometry‐isolated sputum macrophages comparing NA (n = 7) and non‐neutrophilic asthma (NNA, n = 13). qPCR validation of RNASeq results was performed (NA n = 13, NNA n = 23). Pathway analysis (PANTHER, STRING) of differentially expressed genes (DEGs) was performed. Gene set variation analysis (GSVA) was used to test for enrichment of NA macrophage transcriptomic signatures in whole sputum microarray (cohort 1 ‐ controls n = 16, NA n = 29, NNA n = 37; cohort 2 U‐BIOPRED ‐ controls n = 16, NA n = 47, NNA n = 57). Results: Flow cytometry‐sorting significantly enriched sputum macrophages (99.4% post‐sort, 44.9% pre‐sort, p <.05). RNASeq analysis confirmed macrophage purity and identified DEGs in NA macrophages. Selected DEGs (SLAMF7, DYSF, GPR183, CSF3, PI3, CCR7, all p <.05 NA vs. NNA) were confirmed by qPCR. Pathway analysis of NA macrophage DEGs was consistent with responses to bacteria, contribution to neutrophil recruitment and increased expression of phagocytosis and efferocytosis factors. GSVA demonstrated neutrophilic macrophage gene signatures were significantly enriched in whole sputum microarray in NA vs. NNA and controls in both cohorts. Conclusions: We demonstrate a pathophysiologically relevant sputum macrophage transcriptomic programme in NA. The finding that there is transcriptional activation of inflammatory programmes in cell types other than neutrophils supports the concept of NA as a specific endotype. [ABSTRACT FROM AUTHOR]

Keywords: asthma; bioinformatics; endotypes; precision medicine; systems biology EN asthma bioinformatics endotypes precision medicine systems biology 380 383 4 01/09/21 20210101 NES 210101 I To the Editor, i Asthma is a complex heterogeneous disease that presents with varying degrees of severity. We identified four optimal clusters (TAC*1, TAC*2, TAC*3a and TAC*3b) (Figure S3), in agreement with our previous clustering1 where TAC*3a and TAC*3b were combined. Asthma, bioinformatics, endotypes, precision medicine, systems biology. [Extracted from the article]

Influenza vaccine effectiveness and immunogenicity can be compromised with repeated vaccination. We assessed immunological markers in a cohort of healthcare workers (HCW) from six public hospitals around Australia during 2020-2021. Sera were collected pre-vaccination and ~14 and ~ 180 days post-vaccination and assessed in haemagglutination inhibition assay against egg-grown vaccine and equivalent cell-grown viruses. Responses to vaccination were compared by the number of prior vaccinations. Baseline sera were available for 595 HCW in 2020 and 1031 in 2021. 5% had not been vaccinated during five years prior to enrolment and 55% had been vaccinated every year. Post-vaccination titres for all vaccine antigens were lowest among HCW vaccinated in all 5-prior years and highest among HCW with 0 or 1 prior vaccinations, even after adjustment. This was observed for both influenza A subtypes and was dependent on pre-vaccination titre. Expanded cohorts are needed to better understand how this translates to vaccine effectiveness., Competing Interests: Declarations Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: AF, AK, SGS report financial support was provided by National Institutes of Health. AF reports funding/grants from Sanofi Aventis, France. HM reports funding/grants from bioCSL, Pfizer Inc, GlaxoSmithKline. PW reports funding/grants from GlaxoSmithKline Inc, Krystal Biotech, Inc. Vertex Pharmaceuticals, Sanofi. SGS reports consulting for Pfizer Inc, Moderna Inc, Seqirus, Evo Health and Novavax. ACC, CCB are previous Chairs of the Australian Technical Advisory Group on Immunisation (ATAGI). The opinions in this study may not reflect the policy of ATAGI or the Australian Government regarding COVID-19 vaccines.