title: Characterisation of lymphocyte subpopulations in infantile haemangioma.
abstract: OBJECTIVE
  Interstitial CD45+ cells and T lymphocytes have previously been demonstrated within infantile haemangioma (IH). This study investigated the expression of B and T lymphocyte markers by the CD45+ population, and the expression of Thy-1, a marker of thymocyte progenitors, which have the ability to give rise to both B and T cells.
  
  
  METHODS
  Immunohistochemical (IHC) staining was performed on proliferating and involuted IHs for the expression of CD45, CD3, CD20, CD79a, Thy-1 and CD34. The presence of mRNA corresponding to CD45, CD3G, CD20 and Thy-1 was confirmed by reverse transcriptase-polymerase chain reaction in snap-frozen IH tissues. Cell counting of 3,3-diaminobenzidine IHC-stained slides was performed on CD45+ only cells and dually stained CD45+/CD3+ cells or CD45+/CD20+ cells and analysed statistically. In situ hybridisation and mass spectrometry were also performed to confirm the presence and abundance of Thy-1, respectively.
  
  
  RESULTS
  IHC staining showed a subpopulation of CD45+ interstitial cells that expressed the T lymphocyte marker, CD3, and another subpopulation that expressed the B lymphocyte marker, CD20, in proliferating and diminished in involuted IHs. The abundant expression of Thy-1 on the endothelium of proliferating, but not involuted IH, was demonstrated by IHC staining and confirmed by in situ hybridisation and mass spectrometry.
  
  
  CONCLUSIONS
  Both B and T lymphocytes are present within the interstitium of proliferating and involuted IH. The expression of Thy-1 by the endothelium suggests that B and T cells in IH may have originated from within the lesion, rather than migrating from the peripheral circulation.
authors.affiliation: Gillies McIndoe Research Institute, Wellington, New Zealand.
authors.forename: Elysia M S
authors.initials: EM
authors.lastname: Tan
authors.affiliation: Gillies McIndoe Research Institute, Wellington, New Zealand.
authors.forename: Tinte
authors.initials: T
authors.lastname: Itinteang
authors.affiliation: Gillies McIndoe Research Institute, Wellington, New Zealand.
authors.forename: Daria A
authors.initials: DA
authors.lastname: Chudakova
authors.affiliation: Gillies McIndoe Research Institute, Wellington, New Zealand.
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Dunne
authors.affiliation: Gillies McIndoe Research Institute, Wellington, New Zealand University of Auckland, Auckland, New Zealand.
authors.forename: Reginald
authors.initials: R
authors.lastname: Marsh
authors.affiliation: Gillies McIndoe Research Institute, Wellington, New Zealand.
authors.forename: Helen D
authors.initials: HD
authors.lastname: Brasch
authors.affiliation: Gillies McIndoe Research Institute, Wellington, New Zealand.
authors.forename: Paul F
authors.initials: PF
authors.lastname: Davis
authors.affiliation: Gillies McIndoe Research Institute, Wellington, New Zealand Centre for the Study & Treatment of Vascular Birthmarks, Wellington Regional Plastic, Maxillofacial & Burns Unit, Hutt Hospital, Wellington, New Zealand.
authors.forename: Swee T
authors.initials: ST
authors.lastname: Tan
mesh_terms: D018951:Antigens, CD20 / Q000032:analysis; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000235:genetics; D017252:CD3 Complex / Q000032:analysis; D019070:Cell Lineage; D049109:Cell Proliferation; D042783:Endothelial Cells / Q000276:immunology / Q000473:pathology; D006391:Hemangioma / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D017403:In Situ Hybridization; D007223:Infant; D017493:Leukocyte Common Antigens / Q000032:analysis / Q000235:genetics; D010641:Phenotype; D012333:RNA, Messenger / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000473:pathology; D053719:Tandem Mass Spectrometry; D018800:Thy-1 Antigens / Q000032:analysis / Q000235:genetics
chemical_list: D018951:Antigens, CD20; D014408:Biomarkers, Tumor; D017252:CD3 Complex; D012333:RNA, Messenger; D018800:Thy-1 Antigens; D017493:Leukocyte Common Antigens; C516769:PTPRC protein, human
keywords: HAEMATOLOGY; IMMUNOHISTOCHEMISTRY; LYMPHOCYTES; PAEDIATRIC PATHOLOGY; VASCULAR TUMOURS