title: Increased complement C1q level marks active disease in human tuberculosis.
abstract: BACKGROUND
  Complement functions as an important host defense system and complement C5 and C7 have been implicated in immunopathology of tuberculosis. However, little is known about the role of other complement components in tuberculosis.
  
  
  METHODS
  Complement gene expression in peripheral blood mononuclear cells of tuberculosis patients and controls were determined using whole genome transcriptional microarray assays. The mRNA and protein levels of three C1q components, C1qA, C1qB, and C1qC, were further validated by qRT-PCR and enzyme-linked immunosorbent assay, respectively. The percentages of C1q expression in CD14 positive cells were determined by flow cytometry. Finally, C1qC protein level was quantified in the pleural fluid of tuberculosis and non-tuberculosis pleurisy.
  
  
  RESULTS
  C1q expression increases significantly in the peripheral blood of patients with active tuberculosis compared to healthy controls and individuals with latent TB infection. The percentage of C1q-expressing CD14 positive cells is significantly increased in active TB patients. C1q expression in the peripheral blood correlates with sputum smear positivity in tuberculosis patients and is reduced after anti-tuberculosis chemotherapy. Notably, receiver operating characteristic analysis showed that C1qC mRNA levels in peripheral blood efficiently discriminate active from latent tuberculosis infection and healthy controls. Additionally, C1qC protein level in pleural effusion shows improved power in discriminating tuberculosis from non-tuberculosis pleurisy when compared to other inflammatory markers, such as IL-6 and TNF-α.
  
  
  CONCLUSIONS
  C1q expression correlates with active disease in human tuberculosis. C1q could be a potential diagnostic marker to discriminate active tuberculosis from latent tuberculosis infection as well as tuberculosis pleurisy from non-tuberculosis pleurisy.
authors.affiliation: Department of Infectious Diseases, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China; Shenzhen Key Laboratory of Infection and Immunity, Shenzhen Third People's Hospital, Guangdong Medical College, Shenzhen, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Guangdong Key Laboratory for Emerging Infectious Diseases, Shenzhen Third People's Hospital, Shenzhen, China; Shenzhen Key Laboratory of Infection and Immunity, Shenzhen Third People's Hospital, Guangdong Medical College, Shenzhen, China.
authors.forename: Qianting
authors.initials: Q
authors.lastname: Yang
authors.affiliation: Guangdong Key Laboratory for Emerging Infectious Diseases, Shenzhen Third People's Hospital, Shenzhen, China; Shenzhen Key Laboratory of Infection and Immunity, Shenzhen Third People's Hospital, Guangdong Medical College, Shenzhen, China.
authors.forename: Yueqiang
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Guangdong Key Laboratory for Emerging Infectious Diseases, Shenzhen Third People's Hospital, Shenzhen, China.
authors.forename: Mingxia
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Institute of Pathogen Biology, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: Haiying
authors.initials: H
authors.lastname: Liu
authors.affiliation: Guangdong Key Laboratory for Emerging Infectious Diseases, Shenzhen Third People's Hospital, Shenzhen, China.
authors.forename: Guoliang
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Shenzhen Key Laboratory of Infection and Immunity, Shenzhen Third People's Hospital, Guangdong Medical College, Shenzhen, China.
authors.forename: Qunyi
authors.initials: Q
authors.lastname: Deng
authors.affiliation: Shenzhen Key Laboratory of Infection and Immunity, Shenzhen Third People's Hospital, Guangdong Medical College, Shenzhen, China; Shanghai-MOST Key Laboratory of Disease and Health Genomics, National Engineering Center for Biochip at Shanghai, Shanghai, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Infectious Diseases, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Gao
authors.affiliation: Guangdong Key Laboratory for Emerging Infectious Diseases, Shenzhen Third People's Hospital, Shenzhen, China.
authors.forename: Boping
authors.initials: B
authors.lastname: Zhou
authors.affiliation: Department of Infectious Diseases and Immunology, Sydney Medical School, The University of Sydney University, Australia.
authors.forename: Carl G
authors.initials: CG
authors.lastname: Feng
authors.affiliation: Guangdong Key Laboratory for Emerging Infectious Diseases, Shenzhen Third People's Hospital, Shenzhen, China; Shenzhen Key Laboratory of Infection and Immunity, Shenzhen Third People's Hospital, Guangdong Medical College, Shenzhen, China.
authors.forename: Xinchun
authors.initials: X
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000378:metabolism*; D015922:Complement C1q / Q000378:metabolism*; D005260:Female; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D014376:Tuberculosis / Q000378:metabolism* / Q000473:pathology*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D015922:Complement C1q