title: Discordant CD38 measurement of CD8+ T lymphocytes using fluorescein conjugates in comparison with phycoerythrin conjugates.
abstract: BACKGROUND
  We have previously shown that monitoring of CD38 expression can be used as a marker for antiretroviral drug efficacy in HIV infected patients. However, the detection of CD38 expression may be affected by the sensitivity of the fluorochrome conjugated reagent.
  
  
  OBJECTIVE
  In this study, we determined the level of CD38 expression using PE and FITC conjugated anti-CD38 monoclonal antibodies in different groups of HIV infected patients.
  
  
  METHODS
  The frequency and mean fluorescence intensity of CD38 expression using PE and FITC conjugated anti-CD38 monoclonal antibodies were detected by flow cytometry either alone or in combination with HLA-DR. A correlation between CD38 expression and CD4 count, the percentage of CD4 or viral load in antiretroviral drug naive HIV infected patients was performed. The results were compared with those for antiretroviral treated HIV infected patients who responsed to therapy and patients with virological failure.
  
  
  RESULTS
  We found that while both reagents had the ability to detect a high frequency of CD38 expressing cells in untreated patients, only PE conjugated reagent provided correlation with markers for disease progression. More importantly, FITC conjugated reagent cannot monitor the increase in CD38 expression in patients who showed virological failure.
  
  
  CONCLUSIONS
  The results from this study suggest that a cautious selection of fluorochrome conjugated reagents and a method for utilizing the data are extremely critical in the use of CD38 expression as a monitoring tool for ART efficacy.
authors: Center of Excellence for Flow Cytometry, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand. sinol@mahidol.ac.th
authors: Nattawat
authors: N
authors: Onlamoon
authors: Sutchana
authors: S
authors: Tabprasit
authors: Kasama
authors: K
authors: Sukapirom
authors: Korakot
authors: K
authors: Polsira
authors: Palanee
authors: P
authors: Ammaranond
authors: Somying
authors: S
authors: Loharungsikul
authors: Kovit
authors: K
authors: Pattanapanyasat
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000378:metabolism*; D023241:Antiretroviral Therapy, Highly Active; D054316:Biomarkers, Pharmacological / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology / Q000821:virology; D002469:Cell Separation; D018450:Disease Progression; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D006678:HIV / Q000472:pathogenicity / Q000502:physiology*; D015658:HIV Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000276:immunology / Q000473:pathology; D006801:Humans; D010799:Phycoerythrin / Q000378:metabolism; D012680:Sensitivity and Specificity; D019562:Viral Load
chemical_list: D054316:Biomarkers, Pharmacological; D010799:Phycoerythrin; D051997:ADP-ribosyl Cyclase 1; D016650:Fluorescein-5-isothiocyanate