title: Histamine H1and H4receptor expression on the ocular surface of patients with chronic allergic conjunctival diseases.
abstract: BACKGROUND
  This study investigated the histamine H1and H4receptors mRNA (H1R and H4R, respectively) expression on the ocular surface of patients with chronic forms of allergic conjunctival diseases to determine whether they can serve as biomarkers for allergic inflammation in the conjunctiva.
  
  
  METHODS
  We examined 19 patients with vernal or atopic keratoconjunctivitis (AKC/VKC group) and 15 healthy volunteers (control group). The AKC/VKC group was divided into active and stable stage subgroups. Specimens were obtained from the upper tarsal conjunctiva of each participant using a modified impression cytology method. H1R, H4R, and eotaxin-1, -2, and -3 mRNA (eotaxin-1, eotaxin-2, eotaxin-3, respectively) expression was determined by real-time RT-PCR. Immunohistochemical analysis for eosinophil cationic protein (ECP), eosinophil major basic protein (MBP), eotaxin-2, and histamine H4receptor (H4R) were performed using conjunctival smears.
  
  
  RESULTS
  The number of H4R-positive patients was higher in the active than the stable stage subgroup and control group, whereas no difference was observed for H1R. H1R levels were higher in the active than in the stable stage subgroup, while those of H4R were higher in the active stage subgroup than in the control group. H1R and H4R levels were correlated with eotaxin-2 level. In immunohistochemical analysis, H4R revealed their expression on eosinophils in conjunctival smears of patients with AKC/VKC.
  
  
  CONCLUSIONS
  H4R is useful as biomarkers of allergic inflammation on ocular surfaces. Most notably, H4R expressed on eosinophils is useful as a biomarker of eosinophilic inflammation of the ocular surface.
authors.affiliation: Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Tokyo, Japan. Electronic address: inada.noriko@nihon-u.ac.jp.
authors.forename: Noriko
authors.initials: N
authors.lastname: Inada
authors.affiliation: Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Shoji
authors.affiliation: Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Shiraki
authors.affiliation: Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Aso
authors.affiliation: Division of Ophthalmology, Department of Visual Sciences, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Yamagami
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers; D016022:Case-Control Studies; D054413:Chemokine CCL11 / Q000235:genetics / Q000378:metabolism; D054423:Chemokine CCL24 / Q000235:genetics / Q000378:metabolism; D002648:Child; D002908:Chronic Disease; D003233:Conjunctivitis, Allergic / Q000175:diagnosis / Q000188:drug therapy / Q000235:genetics* / Q000276:immunology*; D018450:Disease Progression; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011969:Receptors, Histamine H1 / Q000235:genetics* / Q000378:metabolism; D000074040:Receptors, Histamine H4 / Q000235:genetics* / Q000378:metabolism; D055815:Young Adult
chemical_list: D015415:Biomarkers; D054413:Chemokine CCL11; D054423:Chemokine CCL24; D012333:RNA, Messenger; D011969:Receptors, Histamine H1; D000074040:Receptors, Histamine H4
keywords: Atopic keratoconjunctivitis; Histamine receptor; Ocular surface; Real-time RT-PCR; Vernal keratoconjunctivitis