Altered regulation of the T-cell system in patients with CRPS.

The aim of this study was to investigate T-cell subsets and immunomodulatory factors in patients with complex regional pain syndrome (CRPS). We found decreased numbers of pro-inflammatory Th17 cells in patients with CRPS as compared to healthy volunteers. The expression of Th17 related RORγT mRNA was also significantly decreased. Patients with CRPS showed an increased proportion of CD39+ Tregs. CD39 is a known inhibitor of Th17 cell differentiation. Systemic cytokine levels were almost unchanged in patients with CRPS. These findings suggest that the decrease in Th17 cells in CRPS is regulated by an increase in CD39+ Tregs and that this anti-inflammatory T-cell shift may be a mechanism to control inflammation in CRPS. GERMAN CLINICAL TRIAL REGISTER: Registration Trial DRKS00005954.