title: Skin basement membrane zone: a depository for circulating microbial antigen evoking psoriasis and autoimmunity.
abstract: BACKGROUND
  Elevated levels of antibody to streptococcal exoenzymes have been found in patients with psoriasis or psoriatic arthritis. Research on the role of streptococcal antigen in psoriasis has been hampered by a potential molecular mimicry between streptococcal epitopes and human epidermal keratin.
  
  
  OBJECTIVE
  Evidence of microbial product was sought in skin biopsies of psoriasis patients thought clinically to have either streptococcal carrier state or gastrointestinal candidal colonization. A polyclonal antibody to streptococcal-derived exoenzymes unlikely to share antigenic structures with normal human skin, and an anticandidal antibody, were used with linked streptavidin biotin amplification stain.
  
  
  RESULTS
  The predicted microbial product appeared heavily in lesional epidermis, but unexpectedly also as a thin deposit along the skin basement membrane zone (SBMZ) of apparently unaffected skin. Staining was negative for nonpsoriatic subjects.
  
  
  CONCLUSIONS
  The findings support a direct effect of microbial antigen in psoriasis. They also suggest an important role for SBMZ as a very large adhesive surface in the first step of a process of percutaneous epidermal elimination of foreign antigens and microbial toxins. The many autoimmune phenomena seen so often at the SBMZ are probably a physiologic part of this important immune function. Efforts to enhance the adhesive properties of SBMZ should be exploitable for both diagnostic and therapeutic benefit.
authors.affiliation: Department of Medicine (Dermatology) and Preventive Medicine, University of Tennessee, Memphis, TN 38104-7514, USA.
authors.forename: Patricia W
authors.initials: PW
authors.lastname: Noah
authors.forename: Charles R
authors.initials: CR
authors.lastname: Handorf
authors.forename: Robert B
authors.initials: RB
authors.lastname: Skinner
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Mandrell
authors.forename: E William
authors.initials: EW
authors.lastname: Rosenberg
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis*; D000946:Antigens, Fungal / Q000032:analysis; D015551:Autoimmunity; D001485:Basement Membrane / Q000276:immunology*; D002176:Candida albicans; D006801:Humans; D007150:Immunohistochemistry; D011565:Psoriasis / Q000276:immunology / Q000382:microbiology* / Q000473:pathology; D012867:Skin / Q000276:immunology* / Q000473:pathology; D013297:Streptococcus pyogenes / Q000201:enzymology / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D000946:Antigens, Fungal