@article {FernandezERJ-01826-2015, author = {Isis E. Fernandez and Flavia R. Greiffo and Marion Frankenberger and Julia Bandres and Katharina Heinzelmann and Claus Neurohr and Rudolf Hatz and Dominik Hartl and J{\"u}rgen Behr and Oliver Eickelberg}, title = {Peripheral blood myeloid-derived suppressor cells reflect disease status in idiopathic pulmonary fibrosis}, elocation-id = {ERJ-01826-2015}, year = {2016}, doi = {10.1183/13993003.01826-2015}, publisher = {European Respiratory Society}, abstract = {Idiopathic pulmonary fibrosis (IPF) is a fibroproliferative disease with irreversible lung function loss and poor survival. Myeloid-derived suppressor cells (MDSC) are associated with poor prognosis in cancer, facilitating immune evasion. The abundance and function of MDSC in IPF is currently unknown.Fluorescence-activated cell sorting was performed in 170 patients (IPF: n=69; non-IPF interstitial lung disease (ILD): n=56; chronic obstructive pulmonary disease (COPD): n=23; healthy controls: n=22) to quantify blood MDSC and lymphocyte subtypes. MDSC abundance was correlated with lung function, MDSC localisation was performed by immunofluorescence. Peripheral blood mononuclear cell (PBMC) mRNA levels were analysed by qRT-PCR.We detected increased MDSC in IPF and non-IPF ILD compared with controls (30.99{\textpm}15.61\% versus 18.96{\textpm}8.17\%, p<=0.01). Circulating MDSC inversely correlated with maximum vital capacity (r= -0.48, p<=0.0001) in IPF, but not in COPD or non-IPF ILD. MDSC suppressed autologous T-cells. The mRNA levels of co-stimulatory T-cell signals were significantly downregulated in IPF PBMC. Importantly, CD33+CD11b+ cells, suggestive of MDSC, were detected in fibrotic niches of IPF lungs.We identified increased MDSC in IPF and non-IPF ILD, suggesting that elevated MDSC may cause a blunted immune response. MDSC inversely correlate with lung function only in IPF, identifying them as potent biomarkers for disease progression. Controlling expansion and accumulation of MDSC, or blocking their T-cell suppression, represents a promising therapy in IPF.Circulating myeloid-derived suppressor cells are increased in IPF and inversely correlate with lung function http://ow.ly/6rDm301BpvC}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/early/2016/08/31/13993003.01826-2015}, eprint = {https://erj.ersjournals.com/content/early/2016/08/31/13993003.01826-2015.full.pdf}, journal = {European Respiratory Journal} }