title: Immunocytochemical detection of Mycobacterium Tuberculosis complex specific antigen, MPT64, improves diagnosis of tuberculous lymphadenitis and tuberculous pleuritis.
abstract: BACKGROUND
  A rapid, sensitive and accurate laboratory diagnosis is of prime importance in suspected extrapulmonary tuberculosis (EPTB) cases. However, traditional techniques for the detection of acid-fast bacilli have limitations. The aim of the study was to evaluate the diagnostic value of immunocytochemical staining for detection of Mycobacterium tuberculosis complex specific antigen, MPT64, in aspirates from pleural effusions and lymph nodes, the most common presentations of EPTB.
  
  
  METHODS
  A cross-sectional study was conducted by including patients at Tikur Anbessa Specialized Hospital and the United Vision Medical Services from December 2011 to June 2012. Lymph node aspirates and pleural fluid samples were collected and analyzed from a total of 51 cases (26 tuberculous (TB) pleuritis and 25 TB lymphadenitis) and 67 non-TB controls. Each specimen was subjected to Ziehl-Neelsen (ZN) staining, culture on Lowenstein- Jensen (LJ) medium, cytological examination, Polymerase Chain Reaction (PCR) using IS1081gene sequence as a primer and immunocytochemistry (ICC) with polyclonal anti-MPT64 antibody. All patients were screened for HIV.
  
  
  RESULTS
  ICC was positive in 38 of 51 cases and in the 7 of 67 controls giving an overall sensitivity and specificity of 74.5% and 89.5%, respectively. Using IS1081-PCR as a reference method, the sensitivity and specificity, positive and negative predictive value of ICC was 88.1%, 89.5%, 82.2% and 93.2%, respectively. The case detection rate increased from 13.7% by ZN stain to 19.6% by LJ culture, to 66.7% by cytology and 74.5% by ICC.
  
  
  CONCLUSIONS
  Immunocytochemistry with anti-MPT64 antigen improved detection of TB in pleural effusion and lymph node aspirates. Further studies using monoclonal antibodies on samples from other sites of EPTB is recommended to validate this relatively simple diagnostic method for EPTB.
authors.forename: Agerie
authors.initials: A
authors.lastname: Tadele
authors.forename: Demissew
authors.initials: D
authors.lastname: Beyene
authors.forename: Jemal
authors.initials: J
authors.lastname: Hussein
authors.forename: Tuffa
authors.initials: T
authors.lastname: Gemechu
authors.forename: Asaye
authors.initials: A
authors.lastname: Birhanu
authors.forename: Tehmina
authors.initials: T
authors.lastname: Mustafa
authors.forename: Aster
authors.initials: A
authors.lastname: Tsegaye
authors.forename: Abraham
authors.initials: A
authors.lastname: Aseffa
authors.forename: Lisbet
authors.initials: L
authors.lastname: Sviland
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000276:immunology* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D010996:Pleural Effusion / Q000276:immunology* / Q000382:microbiology; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014388:Tuberculosis, Lymph Node / Q000175:diagnosis* / Q000382:microbiology; D014396:Tuberculosis, Pleural / Q000175:diagnosis* / Q000382:microbiology; D055815:Young Adult
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C080865:MPB64 protein, Mycobacterium