CD8A and complex regional pain syndrome: FlowSOM analysis identified significantly higher numbers of central memory CD8+ T lymphocytes (CD3+CD8+CD45RO+CCR7+) in the CRPS group compared to controls (t26 = 2.163, P < 0.05), whereas the number of naïve, effector and effector memory CD8+ cells were stable across both groups (Fig. 2a).