title: The involvement of immunoglobulin E isotype switch in scleroderma skin tissue.
abstract: BACKGROUND
  The involvement of mast cell, which is activated by immunoglobulin E (IgE), has been reported in the formation of systemic sclerosis (SSc) abnormality. IgE is generated with isotype switch. During isotype switch, switch circles resulting from direct mu to epsilon, or from sequential mu to gamma via epsilon switching will be created.
  
  
  OBJECTIVE
  We studied whether switching occurs in SSc.
  
  
  METHODS
  We used nested polymerase chain reaction to analyze the S fragments from switch circles. Fifty-two patients with SSc, and 62 healthy women were studied.
  
  
  RESULTS
  Neither of 62 normal skin tissues showed direct switch, nor sequential switch. Neither of seven normal whole blood cells showed direct switch, nor sequential switch. In 52SSc skin tissues, three (5.8%) showed direct switch, and two (3.8%) showed sequential switch. As a result, five (9.6%) of SSc skin tissue showed immunogobulin E class switch. These results were confirmed by DNA sequencing.
  
  
  CONCLUSIONS
  These results demonstrated that isotype switch to the epsilon locus achieved by direct and/or sequential switch are involved in SSc skin.
authors.affiliation: Department of Dermatology, Koshigaya Hospital, Dokkyo University School of Medicine, Koshigaya, Saitama, Japan. tohtsuka@dokkyomed.ac.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Ohtsuka
authors.forename: Soji
authors.initials: S
authors.lastname: Yamazaki
mesh_terms: D000328:Adult; D000368:Aged; D001483:Base Sequence; D003001:Cloning, Molecular; D005260:Female; D006801:Humans; D017578:Immunoglobulin Class Switching; D007073:Immunoglobulin E / Q000737:chemistry* / Q000235:genetics; D007132:Immunoglobulin Isotypes / Q000737:chemistry*; D007139:Immunoglobulin epsilon-Chains / Q000737:chemistry; D007148:Immunoglobulin mu-Chains / Q000737:chemistry; D008875:Middle Aged; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D012595:Scleroderma, Systemic / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D017422:Sequence Analysis, DNA; D012867:Skin / Q000276:immunology / Q000473:pathology
chemical_list: D007132:Immunoglobulin Isotypes; D007139:Immunoglobulin epsilon-Chains; D007148:Immunoglobulin mu-Chains; D007073:Immunoglobulin E