title: The application of a monoclonal antibody to CD62L on paraffin-embedded tissue samples in the assessment of the cutaneous T-cell infiltrates.
abstract: BACKGROUND
  A reduction in the expression of the pan T-cell markers CD7 and CD62L supports an endogenous T-cell dyscrasia. Previously, clone availability for CD62L restricted its application to frozen tissue sections.
  
  
  METHODS
  A nonavidin/biotin technique to examine CD3, CD62L, and CD7 in paraffin formalin-fixed tissue in non-neoplastic and neoplastic T-cell infiltrates.
  
  
  RESULTS
  In the reactive group, CD62L manifested a 15 and 22% reduction in epidermal and dermal staining, respectively; there was a 42 and 31% reduction in epidermal and dermal CD7 staining. In lymphomatoid hypersensitivity, CD62L showed a 24 and 9% reduction in epidermal and dermal staining, respectively; CD7 staining demonstrated reduced staining by 70 and 66% in the epidermis and dermis. In the non-lymphomatous endogenous T-cell dyscrasia and lymphoma categories, an 80% diminution in CD62L and CD7 expression was seen.
  
  
  CONCLUSIONS
  CD62L can be successfully applied in formalin-fixed tissue and exhibits enhanced specificity compared to CD7 in the evaluation of cutaneous T-cell infiltrates. Both CD62L and CD7 in paraffin-embedded, formalin-fixed tissue are useful diagnostic adjuncts, especially in regard to the discrimination of lymphomatoid hypersensitivity reactions from true endogenous T-cell dyscrasia.
authors.affiliation: Department of Pathology, The Ohio State University, Columbus, OH 43210, USA. magro-1@medctr.osu.edu
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Magro
authors.forename: Mandi P
authors.initials: MP
authors.lastname: Sachdeva
authors.forename: A Neil
authors.initials: AN
authors.lastname: Crowson
authors.forename: Alan
authors.initials: A
authors.lastname: Barusevicius
authors.forename: Peter N
authors.initials: PN
authors.lastname: Baran
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Kovatich
mesh_terms: D000911:Antibodies, Monoclonal; D005404:Fixatives; D005557:Formaldehyde; D006801:Humans; D019041:L-Selectin / Q000276:immunology / Q000378:metabolism*; D008232:Lymphoproliferative Disorders / Q000378:metabolism* / Q000473:pathology; D016612:Paraffin Embedding / Q000379:methods*; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology; D013601:T-Lymphocytes / Q000378:metabolism* / Q000473:pathology; D016707:Tissue Fixation
chemical_list: D000911:Antibodies, Monoclonal; D005404:Fixatives; D019041:L-Selectin; D005557:Formaldehyde