TNF and complex regional pain syndrome: Evaluation of plasma levels of cytokines, chemokines, and their soluble receptors in CRPS patients vs gender-matched and age matched healthy controlsSignificant changes were found in CRPS patients compared with healthy controlsTwo clusters were identified in CRPS subjectsTNF-α was the most important category for cluster separationWhen present, increased plasma levels of TNF-alpha correlated with disease duration and severity