All CRPS patients were evaluated and blood samples obtained while taking their current medications. Medical

history and self-reported values for height and weight were obtained from normal healthy control subjects. Thermal detection thresholds were determined using the TSA-II NeuroSensory Analyzer (Medoc Advanced Medical Systems US, Minneapolis, MN, USA). The device consists of a computer-controlled thermoelectric probe with a surface area of 9 cm2 that is attached using a Velcro strap to the area of skin to be tested (thenar eminence in the hands and the dorsal foot). For each trial the thermal stimulator starts at a thermoneutral baseline temperature of 32°C, and increases for warming thresholds, or decreases for cooling thresholds, linearly at a rate of 1°C per second, until the subject pushes a button that stops and records the temperature DMXAA ic50 and returns the unit to the baseline temperature. Three trials are averaged for cool and warm detection thresholds for each site tested. Thermal pain thresholds were determined at the same sites and using the same method described above for thermal detection thresholds. The only difference was that for thermal pain trials, the subject was instructed to push the control button (which immediately resets the stimulator back to baseline temperature) when

the thermal stimulus (cold or hot) becomes painful. The TSA-II hardware automatically resets if the temperature reaches −10°C (for cooling) or 50°C (for heating) and the control button has not been pushed. This temperature range has been determined to selleck products not cause damage to skin or underlying tissue. Normative values for thermal detection and pain thresholds were obtained from published studies [32,33]. Venous blood samples were collected into ethylenediamine tetraacetic

acid (EDTA)-coated vacutainers between 08:00 h and 12:00 h. Following centrifugation, the buffy coat was resuspended in RPMI-1640 (Mediatech Lck Inc, Manassas, VA, USA) and layered onto Histopaque-1077 (Sigma-Aldrich, St Louis, MO, USA) for separation of peripheral blood mononuclear cells (PBMCs) by gradient centrifugation. The plasma was split into 0·25-ml aliquots and stored at −70°C for cytokine level determination. Isolated PBMCs were washed and resuspended in phosphate-buffered saline (PBS) containing combinations of fluorescent-conjugated antibodies (eBioscience, San Diego, CA, USA) to the following cell surface markers: CD4 [fluorescence activated cell sorter (FITC)], CD8 [phycoerythrin-cyanine5 (PE-Cy5)], CD19 (PE), CD56 (PE), CD14 [allophycocyanin (APC)] and CD16 (FITC). PBMCs were incubated in staining cocktails for 30 min on ice in the dark. After multiple washes to minimize random antibody binding, PBMCs were fixed with 1% paraformaldehyde (Sigma-Aldrich). Samples were then acquired on a FACSCanto flow cytometer (BD Biosciences, San Jose, CA, USA) and analysed using FlowJo Software (Tree Star, Ashland, OR, USA).