title: Local free light chain expression is increased in chronic rhinosinusitis with nasal polyps.
abstract: BACKGROUND
  Free light chain (FLC) concentrations are demonstrated to be increased in different inflammatory disorders and are proposed to mediate mast cell-dependent immune responses. A role for mast cells is suggested in chronic rhinosinusitis with nasal polyposis (CRSwNP), which is characterized by a local Th2 inflammatory response. However, clear mast cell-activating factors are not always apparent. In this study, the presence of FLCs in CRS patients with or without nasal polyps (CRSw/sNP) was investigated and the effect of different treatments on FLC expression was analyzed.
  
  
  METHODS
  Nasal tissue, nasal secretion, and serum of control patients, patients with CRSwNP, and CRSsNP were analyzed for the presence of kappa and lambda FLC. The expression of FLCs in nasal polyp tissue was investigated using immunohistochemistry. In addition, FLC was measured in serum and nasal secretion of nasal polyp patients treated with methylprednisolone, doxycycline, anti-IL-5, or placebo.
  
  
  RESULTS
  Free light chain concentrations were increased in nasal secretion and mucosal tissue homogenates in patients with chronic rhinosinusitis, and this effect was most prominent in CRSwNP patients. Immunohistochemical analysis confirmed the increased FLC concentrations in nasal polyp tissue. In CRSwNP patients, treatment with methylprednisolone or anti-IL-5 resulted in the reduction in systemic or local FLC concentrations, respectively.
  
  
  CONCLUSIONS
  The presence of FLC in CRSwNP and CRSsNP suggests a possible role in mediating the local immune reaction in the paranasal cavities. Furthermore, the decrease in local FLCs after treatment with anti-IL-5 presumes that IL-5 creates an environment that favors FLC production.
authors: Division of Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, the Netherlands.
authors: T
authors: T
authors: Groot Kormelink
authors: L
authors: L
authors: Calus
authors: N
authors: N
authors: De Ruyck
authors: G
authors: G
authors: Holtappels
authors: C
authors: C
authors: Bachert
authors: F A
authors: FA
authors: Redegeld
authors: P
authors: P
authors: Gevaert
mesh_terms: D002908:Chronic Disease; D005260:Female; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000276:immunology / Q000378:metabolism*; D015848:Interleukin-5 / Q000378:metabolism; D008297:Male; D008407:Mast Cells / Q000276:immunology; D009297:Nasal Mucosa / Q000276:immunology / Q000378:metabolism*; D009298:Nasal Polyps / Q000150:complications / Q000276:immunology* / Q000378:metabolism; D012220:Rhinitis / Q000150:complications / Q000276:immunology* / Q000378:metabolism; D012852:Sinusitis / Q000150:complications / Q000276:immunology* / Q000378:metabolism
chemical_list: D007147:Immunoglobulin Light Chains; D015848:Interleukin-5