title: Post-operative recurrent trachomatous trichiasis is associated with increased conjunctival expression of S100A7 (psoriasin).
abstract: BACKGROUND
  Surgery for trachomatous trichiasis (TT) is a key component of the SAFE Strategy for trachoma control. Unfortunately, recurrent TT following surgery is common, probably due to various surgical and disease factors. To develop strategies to reduce recurrence rates it is necessary to understand its pathological basis. In this study we investigated the relationship between recurrent trichiasis and the expression of various cytokines and fibrogenic genes during a two-year follow-up period.
  
  
  RESULTS
  Individuals undergoing surgery for TT were examined at baseline (pre-operative), 6, 12, 18 and 24 months. Conjunctival swab samples were collected from the tarsal conjunctiva for RNA isolation on each occasion. Individuals who developed recurrent TT with at least 3 lashes touching the eye on one or more occasion were designated "cases" and an equal number of "controls" were randomly selected from those without recurrent TT, frequency matched for age and baseline TT severity. The expression of the following genes was measured by quantitative RT-PCR: S100A7, IL1B, CXCL5, TNFA, NOS2A, CTGF, MMP7, MMP9 and MMP12. Thirteen hundred individuals were enrolled and underwent surgery. By two years 122 had developed recurrent TT with at least 3 lashes touching the eye. Recurrent TT was consistently associated across multiple time points with about a 2-fold increase in S100A7 expression (p = 0.008). Clinically visible conjunctival inflammation was associated with increased S100A7, IL1B, CXCL5, MMP9 and MMP12 expression.
  
  
  CONCLUSIONS
  Increased S100A7 expression was associated with trachomatous conjunctival scarring and may be linked to the pathophysiology of recurrent TT. S100A7 expression could be a potential biomarker for this disease process. As part of the epithelial innate immune response S100A7 has multiple actions, potentially contributing to a chronic pro-inflammatory response, which may lead to ongoing tissue damage and increased scarring.
authors.affiliation: London School of Hygiene and Tropical Medicine, London, United Kingdom. matthew.burton@lshtm.ac.uk
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Burton
authors.forename: Saul N
authors.initials: SN
authors.lastname: Rajak
authors.forename: Athumani
authors.initials: A
authors.lastname: Ramadhani
authors.forename: Helen A
authors.initials: HA
authors.lastname: Weiss
authors.forename: Esmael
authors.initials: E
authors.lastname: Habtamu
authors.forename: Bayeh
authors.initials: B
authors.lastname: Abera
authors.forename: Baye
authors.initials: B
authors.lastname: Abera
authors.forename: Paul M
authors.initials: PM
authors.lastname: Emerson
authors.forename: Peng T
authors.initials: PT
authors.lastname: Khaw
authors.forename: David C W
authors.initials: DC
authors.lastname: Mabey
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Holland
authors.forename: Robin L
authors.initials: RL
authors.lastname: Bailey
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers; D016022:Case-Control Studies; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012008:Recurrence; D000075023:S100 Calcium Binding Protein A7; D009418:S100 Proteins / Q000096:biosynthesis* / Q000235:genetics; D014141:Trachoma / Q000150:complications* / Q000175:diagnosis / Q000235:genetics*; D058457:Trichiasis / Q000175:diagnosis / Q000235:genetics*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D000075023:S100 Calcium Binding Protein A7; D009418:S100 Proteins; C089242:S100A7 protein, human