title: Lichen planus and lichenoid drug-induced eruption: a histological and immunohistochemical study.
abstract: BACKGROUND
  Lichenoid drug eruption (LDE) shares similar features with lichen planus (LP), that could reflect the same pathogenesis. In LP, an autoimmune attack is accepted and cytotoxic T-lymphocytes (CD8+) predominate, especially in late lesions. Apoptosis of keratinocytes may be mediated by CD8+ T and NK cells in two distinct ways: by the release of cytotoxic molecules such as perforin and granzyme B or by the Fas/FasL system. The immunological mechanisms involved in LDE are not yet fully established.
  
  
  OBJECTIVE
  Investigate immunohistological features in LP and LDE to add clues to better understand their pathogenesis.
  
  
  METHODS
  Twenty-two patients fulfilled all clinical, laboratory, histopathological, and follow-up features of lichen planus (n = 16) and lichenoid drug eruption (n = 6). Classic histological features favoring LP or LDE were evaluated by two observers. HAM56, MAC387, UCHL-1, OPD4, CD8, Granzyme B, Perforin, and ICAM-1 antibodies were used to decorate the immune infiltrate. Results were analyzed through Pearson correlation, Student's t-test, and linear discriminant analysis.
  
  
  RESULTS
  A higher number of necrotic keratinocytes as well as plasma cells and eosinophils within inflammatory cells were associated with LDE diagnosis. Only in LDE, a correlation was found between the number of T and CD8+ cells and between the number of granzyme B+ cells and apoptotic keratinocytes.
  
  
  CONCLUSIONS
  Our findings suggest a more important role of CD8+ granzyme B-containing cells in LDE group, being its synthesis associated with more intense apoptosis. So, LP and LDE may have a somewhat distinct pathogenesis.
authors.affiliation: Department of Pathology Dermatology, Medical School, UNICAMP, Brazil.
authors.forename: Denise
authors.initials: D
authors.lastname: Lage
authors.forename: Priscila Bianchini
authors.initials: PB
authors.lastname: Juliano
authors.forename: Konradin
authors.initials: K
authors.lastname: Metze
authors.forename: Elemir Macedo
authors.initials: EM
authors.lastname: de Souza
authors.forename: Maria Letícia
authors.initials: ML
authors.lastname: Cintra
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D016923:Cell Death / Q000187:drug effects / Q000276:immunology; D003879:Dermatologic Agents / Q000009:adverse effects* / Q000276:immunology; D003875:Drug Eruptions / Q000276:immunology / Q000473:pathology*; D004804:Eosinophils / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D008010:Lichen Planus / Q000188:drug therapy* / Q000276:immunology; D017512:Lichenoid Eruptions / Q000139:chemically induced / Q000276:immunology / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010950:Plasma Cells / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D055815:Young Adult
chemical_list: D003879:Dermatologic Agents