title: Elevated levels of substance P in tears of patients with allergic conjunctivitis and vernal keratoconjunctivitis.
abstract: BACKGROUND
  Recent studies have suggested that the nervous system may participate in inflammatory processes. Substance P (SP) acts as a chemical mediator as well as a neurotransmitter.
  
  
  OBJECTIVE
  In order to clarify the pathogenesis of ocular allergic diseases, we assessed the concentration of SP in tears.
  
  
  METHODS
  Using a highly sensitive and specific double-antibody enzyme immunoassay (EIA), we determined the SP concentration in tears of 10 patients with seasonal allergic conjunctivitis, 10 with atopic dermatitis without keratoconjunctivitis (AD), 13 with vernal keratoconjunctivitis (VKC) and 65 normal controls. Giemsa's staining for brush cytology samples and histocytological study by immunocytochemical staining of giant papillary conjunctival cells from VKC and normal controls was conducted.
  
  
  RESULTS
  The mean SP level was low in the normal controls and AD, whereas patients with seasonal allergic conjunctivitis and VKC showed significant elevation of SP (P < 0.01). Brush cytology samples showed conjunctival epithelial cells with lymphocytes, neutrophils and eosinophils that were not seen in normal subjects. Histocytological examination demonstrated SP positive cells in the conjunctiva of patients with VKC, but not in normal controls.
  
  
  CONCLUSIONS
  This study suggests that the increased level of SP in tears may contribute to the pathogenesis and severity of ocular allergic diseases.
authors.affiliation: Department of Ophthalmology, Tokyo Dental College, Chiba, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Fujishima
authors.forename: M
authors.initials: M
authors.lastname: Takeyama
authors.forename: T
authors.initials: T
authors.lastname: Takeuchi
authors.forename: I
authors.initials: I
authors.lastname: Saito
authors.forename: K
authors.initials: K
authors.lastname: Tsubota
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D002851:Chromatography, High Pressure Liquid; D003228:Conjunctiva / Q000378:metabolism / Q000473:pathology; D003233:Conjunctivitis, Allergic / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D013373:Substance P / Q000378:metabolism*; D013666:Tears / Q000378:metabolism*
chemical_list: D013373:Substance P