title: Mast cells are involved in inflammatory reactions during Complex Regional Pain Syndrome type 1.
abstract: BACKGROUND
  The Complex Regional Pain Syndrome type 1 (CRPS1) is a complication of surgery or trauma but spontaneous development is also described. Although the pathogenesis remains debatable, afferent, efferent and central nervous system mechanisms are proposed. Recently we showed involvement of the proinflammatory cytokines IL-6 and TNFalpha which is direct evidence for an inflammatory process. Many types of cells, such as activated T lymphocytes, monocytes, macrophages and skin resident cells like mast cells, could contribute to the production of cytokines. Involvement of mast cells is relatively easy to detect by measurement of tryptase.
  
  
  OBJECTIVE
  To establish whether mast cells are involved in the inflammatory reactions during CRPS1.
  
  
  METHODS
  Twenty patients fulfilling the Bruehl criteria with CRPS1 in one extremity were studied. Impairment was assessed by registration of pain and measurement of differences in temperature, volume and mobility between the involved and uninvolved extremity. Blisters were made with a suction method in order to determine cytokines and mast cell derived tryptase in the involved and uninvolved extremity.
  
  
  RESULTS
  In the blister fluid a significant difference (median +/- interquartile range, Wilcoxon signed-ranks test P < 0.05) was found between the involved and uninvolved extremity in IL-6 [53.5 (17.3-225) versus 6.2 (2-20.3) pg/ml], TNFalpha [31 (15.5-131.5) versus 8 (4-39) pg/ml], and tryptase [37 (20.5-62.3) versus 12.5 (6.7-23.5) ng/ml]. There was a significant correlation (0.455) between the intensity of pain and tryptase levels in the involved extremity (Spearman's test, P < 0.05).
  
  
  CONCLUSIONS
  Mast cells are involved in inflammatory reactions during the CRPS1. Mast cells could play a role in the production of cytokines such as TNFalpha.
authors.affiliation: Pain Treatment Center, Department of Anaesthesiology, PO Box 2040, 3000 CA Rotterdam, The Netherlands. f.huygen@erasmusmc.nl
authors.forename: Frank J P M
authors.initials: FJ
authors.lastname: Huygen
authors.forename: Navin
authors.initials: N
authors.lastname: Ramdhani
authors.forename: Albert
authors.initials: A
authors.lastname: van Toorenenbergen
authors.forename: Jan
authors.initials: J
authors.lastname: Klein
authors.forename: Freek J
authors.initials: FJ
authors.lastname: Zijlstra
mesh_terms: D000328:Adult; D001768:Blister / Q000201:enzymology / Q000378:metabolism; D005260:Female; D006801:Humans; D007249:Inflammation / Q000201:enzymology / Q000276:immunology / Q000378:metabolism; D015850:Interleukin-6 / Q000276:immunology / Q000378:metabolism; D008297:Male; D008407:Mast Cells / Q000276:immunology* / Q000378:metabolism; D008875:Middle Aged; D012019:Reflex Sympathetic Dystrophy / Q000201:enzymology / Q000209:etiology / Q000276:immunology* / Q000378:metabolism; D012697:Serine Endopeptidases / Q000378:metabolism; D053802:Tryptases; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000378:metabolism
chemical_list: D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D012697:Serine Endopeptidases; D053802:Tryptases