title: The universal detection of antigens from one skin biopsy specimen.
abstract: BACKGROUND
  Immunohistochemistry is an important tool in dermatology but is limited. Certain antigens can only be preserved in formalin-fixed paraffin-embedded sections, while others can only be detected on frozen sections, resulting in situations where two biopsies are needed. We aimed to develop a technique for universal detection of different antigens out of just one biopsy specimen.
  
  
  METHODS
  Single biopsies were obtained from lesional skin of patients with psoriasis. Standard sample procedures for frozen and paraffin-embedded sections were used. To convert frozen tissue into paraffin-embedded sections, the biopsy specimen was disposed of the embedding medium and subsequently fixed in 10% neutral buffered formalin. We applied various antigen retrieval techniques with alkaline solutions. The differential expression of keratin 10, keratin 15, CD3, CD26 and human beta defensin-2 (HBD-2) was examined using immunohistochemical staining.
  
  
  RESULTS
  We showed that keratin 10 and 15 can be stained on both frozen and paraffin-embedded sections. Staining of paraffin-embedded sections required unmasking with trypsin and Tris-buffered saline Tween solution, respectively. CD3 and CD26 can only be detected on frozen sections, while HBD-2 can only be detected on paraffin-embedded sections.
  
  
  CONCLUSIONS
  We have described a straightforward technique that gives us the opportunity to use just one biopsy specimen to obtain frozen sections as well as paraffin-embedded sections.
authors.affiliation: Department of Dermatology, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands. H.vanderVelden@derma.ucmn.nl
authors.forename: Haike M J
authors.initials: HM
authors.lastname: van der Velden
authors.forename: Peter C M
authors.initials: PC
authors.lastname: van de Kerkhof
authors.forename: Marcel C
authors.initials: MC
authors.lastname: Pasch
authors.forename: Roelie T
authors.initials: RT
authors.lastname: de Boer-van Huizen
authors.forename: Rosanne G
authors.initials: RG
authors.lastname: van Lingen
authors.forename: Piet E J
authors.initials: PE
authors.lastname: van Erp
mesh_terms: D001706:Biopsy; D017252:CD3 Complex / Q000378:metabolism; D018819:Dipeptidyl Peptidase 4 / Q000378:metabolism; D005629:Frozen Sections / Q000379:methods*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D053550:Keratin-10 / Q000378:metabolism; D053569:Keratin-15 / Q000378:metabolism; D016612:Paraffin Embedding / Q000379:methods*; D012871:Skin Diseases / Q000175:diagnosis* / Q000378:metabolism; D013194:Staining and Labeling / Q000379:methods; D023083:beta-Defensins / Q000378:metabolism
chemical_list: D017252:CD3 Complex; C106641:DEFB4A protein, human; D053569:Keratin-15; D023083:beta-Defensins; D053550:Keratin-10; D018819:Dipeptidyl Peptidase 4