Evaluating the Clinical Utility of the T-SPOT.CMV Assay for the Prediction of CMV Reactivation Among Pediatric Patients Undergoing Hematopoietic Cell Transplant

The T-SPOT.CMV test (Oxford Diagnostic Laboratories) measures the strength of T cell responses to CMV specific antigens. Using whole blood samples obtained through a standard blood collection tube, white blood cells (WBC's) are separated and purified. The cells are quantified and placed into specially designed plates where they are challenged with antigens specific to the disease under study. Disease-specific cells responding to these antigens will release immune messenger molecules, called cytokines. We then use chemistry to allow us to visualize those WBCs releasing cytokines (and hence those which react to the antigen), resulting in a spot on the bottom of the plate, corresponding to the footprint of an individual reacting WBC. Finally, we use an automated image analysis system to identify and count each of these spots to give a quantitative readout. That quantitative readout gives us the frequency of responsive disease-specific cells (Oxford Immunotec, 2017).