title: Immunohistochemical Analysis of Scarring Trachoma Indicates Infiltration by Natural Killer and Undefined CD45 Negative Cells.
abstract: The phenotype and function of immune cells infiltrating the conjunctiva in scarring trachoma have yet to be fully characterized. We assessed tissue morphology and immunophenotype of cellular infiltrates found in trachomatous scarring compared to control participants.
  
  
  
  Clinical assessments and conjunctival biopsy samples were obtained from 34 individuals with trachomatous scarring undergoing trichiasis surgery and 33 control subjects undergoing cataract or retinal detachment surgery. Biopsy samples were fixed in buffered formalin and embedded in paraffin wax. Hematoxylin and eosin (H&E) staining was performed for assessment of the inflammatory cell infiltrate. Immunohistochemical staining of single markers on individual sections was performed to identify cells expressing CD3 (T-cells), CD4 (helper T-cells), CD8 (suppressor/cytotoxic T-cells and Natural Killer, NK, cells), NCR1 (NK cells), CD20 (B-cells), CD45 (nucleated hematopoietic cells), CD56 (NK and T-cells), CD68 (macrophages/monocytes) and CD83 (mature dendritic cells). The degree of scarring was assessed histologically using cross-polarized light to visualize collagen fibres.
  
  
  
  Scarring, regardless of clinical inflammation, was associated with increased inflammatory cell infiltrates on H&E and CD45 staining. Scarring was also associated with increased CD8+ and CD56+ cells, but not CD3+ cells, suggestive of a NK cell infiltrate. This was supported by the presence of NCR1+ cells. There was some increase in CD20+ cells, but no evidence for increased CD4+, CD68+ or CD83+ cells. Numerous CD45 negative cells were also seen in the population of infiltrating inflammatory cells in scarred conjunctiva. Disorganization of the normal collagen architecture was strongly associated with clinical scarring.
  
  
  
  These data point to the infiltration of immune cells with a phenotype suggestive of NK cells in conjunctival trachomatous scarring. A large proportion of CD45 negative inflammatory cells were also present. Future work should seek to understand the stimuli leading to the recruitment of these cells and their role in progressive scarring.
authors.affiliation: International Centre for Eye Health, Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.|Kilimanjaro Christian Medical Centre, Moshi, Tanzania.
authors.forename: Victor H
authors.initials: VH
authors.lastname: Hu
authors.affiliation: UCL Institute of Ophthalmology, London, United Kingdom.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Luthert
authors.affiliation: Kilimanjaro Christian Medical Centre, Moshi, Tanzania.|Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Tamsyn
authors.identifier: 0000-0002-1458-6503
authors.initials: T
authors.lastname: Derrick
authors.affiliation: UCL Institute of Ophthalmology, London, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Pullin
authors.affiliation: Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Helen A
authors.initials: HA
authors.lastname: Weiss
authors.affiliation: Kilimanjaro Christian Medical Centre, Moshi, Tanzania.
authors.forename: Patrick
authors.initials: P
authors.lastname: Massae
authors.affiliation: International Centre for Eye Health, Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.|Kilimanjaro Christian Medical Centre, Moshi, Tanzania.
authors.forename: Tara
authors.initials: T
authors.lastname: Mtuy
authors.affiliation: Kilimanjaro Christian Medical Centre, Moshi, Tanzania.
authors.forename: William
authors.initials: W
authors.lastname: Makupa
authors.affiliation: UCL Institute of Ophthalmology, London, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Essex
authors.affiliation: Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: David C W
authors.initials: DC
authors.lastname: Mabey
authors.affiliation: Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Robin L
authors.initials: RL
authors.lastname: Bailey
authors.affiliation: Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Holland
authors.affiliation: International Centre for Eye Health, Department of Clinical Research, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.|Kilimanjaro Christian Medical Centre, Moshi, Tanzania.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Burton
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology; D001706:Biopsy; D019002:CD56 Antigen / Q000032:analysis; D002692:Chlamydia trachomatis / Q000276:immunology; D002921:Cicatrix / Q000276:immunology / Q000473:pathology*; D003228:Conjunctiva / Q000276:immunology / Q000473:pathology; D003713:Dendritic Cells / Q000276:immunology; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000032:analysis; D007150:Immunohistochemistry; D016130:Immunophenotyping; D007249:Inflammation / Q000276:immunology*; D007694:Killer Cells, Natural / Q000276:immunology*; D017493:Leukocyte Common Antigens / Q000032:analysis* / Q000276:immunology; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis; D013194:Staining and Labeling; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D014141:Trachoma / Q000276:immunology* / Q000469:parasitology; D058457:Trichiasis / Q000276:immunology / Q000469:parasitology / Q000473:pathology; D000097802:CD83 Antigen
chemical_list: D015703:Antigens, CD; D019002:CD56 Antigen; D007136:Immunoglobulins; D017493:Leukocyte Common Antigens; D008562:Membrane Glycoproteins; D000097802:CD83 Antigen; C522918:NCAM1 protein, human; C516769:PTPRC protein, human