title: Identifying HIV infection in diagnostic histopathology tissue samples--the role of HIV-1 p24 immunohistochemistry in identifying clinically unsuspected HIV infection: a 3-year analysis.
abstract: OBJECTIVE
  Because of the clinical difficulty in identifying the early stages of human immunodeficiency virus (HIV) infection, the histopathologist often has to consider the diagnosis of HIV in tissue samples from patients with no previous suspicion of HIV infection. The aim was to investigate the practicality and utility of routine HIV-1 p24 immunohistochemistry on tissue samples received at a London histopathology laboratory.
  
  
  RESULTS
  Over a 3-year period, HIV-1 p24 was evaluated immunohistochemically on 123 cases. Of these, 37 (30%) showed positive expression of p24 in lesional follicular dendritic cells (FDCs). Of these 37 cases, 11 were not clinically suspected to be HIV+ and had no prior serological evidence of HIV infection. These cases represented lymph node biopsies, tonsillar and nasopharyngeal biopsies and a parotid excision. In addition to expression on FDCs, in 22 cases (60%), p24 also highlighted mononuclear cells and macrophages. p24 was also useful in confirming the presence of HIV in lymphoid tissue in non-lymphoid organs such as the lung, anus, salivary gland and brain. Immunonegativity occurred in occasional known HIV+ cases, probably related to treatment or tissue processing.
  
  
  CONCLUSIONS
  This study confirms the usefulness of this technique in detecting unsuspected HIV infection in lymphoid and non-lymphoid organs on histopathological material and should be part of routine evaluation of lymph nodes and lymphoid tissue in other organs if morphological or clinical features suggest HIV infection.
authors.affiliation: Department of Histopathology, Guy's and St Thomas' Hospitals, Guy's & St Thomas' Foundation Trust, Westminster Bridge Road, London SE1 7EH, UK. mufaddal.moonim@gstt.nhs.uk
authors.forename: Mufaddal T
authors.initials: MT
authors.lastname: Moonim
authors.forename: Lida
authors.initials: L
authors.lastname: Alarcon
authors.forename: Janet
authors.initials: J
authors.lastname: Freeman
authors.forename: Ula
authors.initials: U
authors.lastname: Mahadeva
authors.forename: Jon D
authors.initials: JD
authors.lastname: van der Walt
authors.forename: Sebastian B
authors.initials: SB
authors.lastname: Lucas
mesh_terms: D000293:Adolescent; D000328:Adult; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D003581:Cytodiagnosis / Q000379:methods*; D042241:Early Diagnosis; D005260:Female; D016655:HIV Core Protein p24 / Q000032:analysis* / Q000276:immunology; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D008221:Lymphoid Tissue / Q000378:metabolism / Q000473:pathology / Q000821:virology; D008297:Male; D008875:Middle Aged; D016612:Paraffin Embedding; D012189:Retrospective Studies
chemical_list: D016655:HIV Core Protein p24