title: Flow cytometric CD4 enumeration of four different HIV-infected blood samples at the cost of one monoclonal antibody reagent.
abstract: BACKGROUND
  The frequency and absolute number of CD4+ T-lymphocytes continue to be one of the major clinical markers for management of HIV/AIDS. The present standard dual-platform (DP) three-color and two-color PanLeucogating flow cytometric (FCM) methods for most developing countries are either expensive if manufacturers' monoclonal antibody reagents are used or limited due to an insufficient supply of generic reagents. Clearly, more affordable FCM methods are needed.
  
  
  OBJECTIVE
  To develop a novel DP FCM method using biotin-streptavidin-fluorochrome labeling in combination with the two standard DP methods for 4 different white blood cells (WBC) using only one monoclonal antibody reagent.
  
  
  METHODS
  The percentage of CD4+ T-lymphocytes in 116 HIV-infected blood samples was determined using our new method. Results were compared with the two standard methods. Correlation and agreement of the pair method were determined using linear regression, Bland-Altman and percent similarity analysis.
  
  
  RESULTS
  Our study showed that percentage of CD4+ T-lymphocyte values obtained from the new method correlated highly with the standard three-color and the two-color methods (r2 = 0.95 {n=52} and 0.97 {n=64}). The mean bias and percent similarity for the new method compared with the two standard methods were -0.53% (limit of agreement {LOA}:-5.22% to +4.16% with percent similarity of 99.28; and -0.22% with LOA of -3.42% to +2.98%, the percent similarity of 98.15, respectively.
  
  
  CONCLUSIONS
  Our FCM method using biotin to label 4 different WBC samples followed by streptavidin staining is reliable for determination of CD4+ T-lymphocytes. Such an approach will significantly reduce the cost for monitoring HIV-infected patients in resource-limited settings.
authors: Center of Excellence for Flow Cytometry, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors: Egarit
authors: E
authors: Noulsri
authors: Surada
authors: S
authors: Lerdwana
authors: Kasama
authors: K
authors: Sukapirom
authors: Charin
authors: C
authors: Thepthai
authors: Nattawat
authors: N
authors: Onlamoon
authors: Boonrat
authors: B
authors: Tassaneetrithep
authors: Kovit
authors: K
authors: Pattanapanyasat
mesh_terms: D000911:Antibodies, Monoclonal / Q000191:economics; D015496:CD4-Positive T-Lymphocytes; D002452:Cell Count; D003362:Cost-Benefit Analysis; D005434:Flow Cytometry; D006678:HIV / Q000276:immunology* / Q000472:pathogenicity; D015658:HIV Infections / Q000175:diagnosis* / Q000191:economics / Q000276:immunology; D006295:Health Resources; D006403:Hematologic Tests / Q000191:economics* / Q000379:methods; D006801:Humans
chemical_list: D000911:Antibodies, Monoclonal