title: Establishment of a healthy human range for the whole blood 'OX40' assay for the detection of antigen-specific CD4+ T cells by flow cytometry.
abstract: Background: Clinical investigation of antigen-specific T cells in potentially immunodeficient patients is an important and often challenging aspect of patient diagnostic work up. Methods for detection of microbial exposure to the T cell compartment exist but are laborious and time consuming. Recently, a whole blood technique involving flow cytometry and detection of CD25 and OX40 (CD134) expression on the surface of activated CD4+ T cells was shown to be accurate and concordant when compared with more traditional methods of antigen-specific T cell detection. Methods: Whole heparinised blood was collected from healthy donors and set up using the 'OX40' assay to detect antigen specific CD4+ T cell responses to Varicella Zoster Virus (VZV), Epstein-Barr Virus (EBV), Cytomegalovirus (CMV), Candida albicans and Streptococcus pneumoniae. Results: The 'OX40' assay technique was clinically validated for routine use in an NHS clinical immunology laboratory by analysis of incubation length (40-50 hours), sample transport time (up to 24 hours at room temperature), concordance with serology testing, proliferation and IFN-γ production. In addition, 63 healthy controls (age range 21-78) were tested for responses to generate a healthy control reference range. Conclusions: The OX40 assay, as presented in this report, represents an economical, rapid, robust whole blood technique to detect antigen-specific T cells which is suitable for clinical immunology diagnostic laboratory use. © 2013 Clinical Cytometry Society.
authors: Department of Immunology, Churchill Hospital, Oxford University Hospitals NHS Trust, Oxford, UK.
authors: Ross
authors: R
authors: Sadler
authors: Elizabeth Al
authors: EA
authors: Bateman
authors: Victoria
authors: V
authors: Heath
authors: Smita Y
authors: SY
authors: Patel
authors: Phillip P
authors: PP
authors: Schwingshackl
authors: Alice C
authors: AC
authors: Cullinane
authors: Lisa
authors: L
authors: Ayers
authors: Berne L
authors: BL
authors: Ferry
keywords: CD4+T cells; Co-stimulation/Co-stimulatory; Diagnostics; Flow cytometry