CD206 upregulation in monocytes within whole blood cultures correlates with lung function in Cystic Fibrosis: a pilot study

Chronic inflammation dominates disease pathogenesis in Cystic Fibrosis (CF) and there is a need to characterise CF immunity. Whole blood cultures offer a cost-effective and non-invasive approach to investigate immune responses within the host environment. Here we used whole blood cultures to investigate the differentiation potential of monocytes (CD45+CD14+ cells) in CF (N=10) and controls (N=8) in the presence and absence of exogenous macrophage-colony stimulatory factor (M-CSF) or granulocyte-macrophage (GM)-CSF with and without interleukin (IL)-4. In CF and control cultures, CD45+CD14+ cells upregulated HLA-DR expression in all instances, and increased CD206 in the presence of GM-CSF with and without IL-4, and CD209 in the presence of GM-CSF and IL-4. In CF, we consistently observed reduced upregulation of CD206 in response to GM-CSF and a positive correlation between CD206 expression and lung function (FEV1). This was unique to cultured monocytes, and not seen with any other marker. These results highlight the potential of whole blood cultures to reveal cellular characteristics in differentiating monocytes related to clinical parameters that could guide the identification of novel biomarkers in CF. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was funded by UKRI-MRC grant [Award number MR/P001033/1] to Luisa Martinez-Pomares, Miguel Camara and Paul Williams, and the National Biofilms Innovation Centre (NBIC) which is an Innovation and Knowledge Centre funded by the Biotechnology and Biological Sciences Research Council, Innovate UK and Hartree Centre [Awards Numbers BB/R012415/1 to MC, LMP and PW and BB/X002950/1 to MC]. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved by the Health Research Authority, REC reference: 17/LO/117, IRAS project ID: 190057. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present work are contained in the manuscript