Immunoreactivity against intracellular domains of desmogleins in pemphigus

In pemphigus vulgaris (PV) and pemphigus foliaceus (PF), most of the autoan tibodies direct against the extracellular domains of desmoglein 1 (Dsg1) or Dsg3, and those antibodies are proved to play a pathogenic role in blister formation in the skin and mucous membranes. However, some pemyhigus sera h ave been reported to react with the intracellular domains of these antigens . In the present study, we examined the reactivity of the sera from various types of pemphigus with recombinant proteins of extracellular and intracel lular domains of human Dsg1 and Dsg3 by immunoblot analysis. We produced th e entire extracellular domain of Dsg1 or Dsg3 fused with mouse IgC2a by bac ulovirus expression. We prepared the intracellular domain of Dsg1 or Dsg3 f used with glutathione-S-transferase by bacterial expression. All of the 31 PV sera reacted with the extracellular domain of Dsg3 and four reacted with the intracellular domain. Six out of 19 PF sera reacted with the extracell ular domain of Dsgl and five reacted with the intracellular domain. In addi tion, some sera of Brazilian PF patients or cases with mixed features of PV and PF also reacted with the intracellular domains of Dsg1 or Dsg3. Althou gh the frequency was low, some sera did react with the intracellular domain of Dsgs. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.