Purpose: The aim of this paper was to identify differentially expressed long non-coding RNAs (lncRNAs) in peripheral blood mononuclear cells (PBMCs) influenced by the infection of multidrug-resistant tuberculosis (MDR-TB).
Materials and methods: IncRNA and mRNA expression profiles in PBMCs derived from healthy controls (HCs) and individuals with MDR-TB and drug-sensitive tuberculosis (DS-TB) were analyzed and compared by microarray assay. Six lncRNAs were randomly selected for validation by using real-time quantitative polymerase chain reaction (RT-qPCR). The biological functions and signaling pathways affected by the differentially expressed mRNAs were investigated by using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway-based approaches. 
Results: Compared with the HC group, 1,429 lncRNAs (983 mRNAs) and 2,040 lncRNAs (1,407 mRNAs) were identified to be deregulated in the MDR-TB group and in the DS-TB group, respectively, and 1,511 lncRNAs and 1,047 mRNAs were identified to be differentially expressed in both MDR-TB and DS-TB groups. Between the three groups, 22 lncRNAs and 38 mRNAs were found deregulated. Most deregulated lncRNAs were from intergenic regions (~55% of the total), natural antisense to protein-coding loci (~32% of the total), or intronic antisense to protein-coding loci (~5% of the total). Significantly enriched signaling pathways regulated by the deregulated mRNAs were mainly associated with natural killer cell-mediated cytotoxicity, antigen processing and presentation, graft-vs-host disease, the transforming growth factor-β signaling pathway, and the Hippo signaling pathway. 
Conclusion: This study is the first to report differentially expressed lncRNAs in PBMCs in response to MDR-TB infection. It revealed that some lncRNAs might be associated with regulating host immune response to MDR-TB infection. Further elucidation of the potential of these deregulated lncRNAs in MDR-TB and its reactivation requires further study.
Keywords: mycobacterium tuberculosis, MDR, molecular characterization, lncRNA, infection