Background: Deregulation of microRNAs (miRNAs)has been associated with various human pathologies including bacterial infections.Aim: To investigate the role of miRNAs as blood biomarkers for the diagnosis of active pulmonary tuberculosis (TB).Materials and methods: We studied 50 patients, classified into 3 groups:(i) 17individuals with latent tuberculosis infection (LTBI) (ii) 17 active pulmonary TB patients (iii) 16 healthy individuals. Blood was collected in a PAXgene Blood RNA tubefor thelater isolation oftotal RNA. MiRNA quantification was performed with SurePrint G3 8x60K miRNA microarrays (Agilent). Real time-quantitative polymerase chain reaction (RT-qPCR)with the miScript PCR System (Qiagen) was used to validateselectedmiRNAexpression levels.Results: MiRNA expression patternswere comparedin whole blood from active TBpatients, LTBI individuals and healthy controls. Aset of miRNAs differentially deregulated during active pulmonary TB vs.LTBI and healthy controlswas identified. We then selected nine miRNAsfor validation in a larger patient cohort. The set of miRNAs consisting of miR-150, miR-21, miR-29cand miR-194 enabled to rapidly diagnose pulmonary TB with 91.21% sensitivity and 87.95% specificity.Conclusions:Theidentified novel miRNA signature opens the possibility of developinga simple, rapid and cheap TB diagnostic test from blood

This work was supported by agrant from the Spanish Ministerio de Ciencia e Innovación SAF2010–21336. Andreas Meyerhans is a researcher founded from the Institucio Catalana de Recerca i Estudis Avancats (ICREA). Irene Latorre wasthe recipient of a joint ERS/SEPAR Long-Term fellowship (LTRF 82-2012)during this work