Bullous systemic lupus erythematosus with autoantibodies recognizing multiple skin basement membrane components, bullous pemphigoid antigen 1, laminin-5, laminin-6, and type VII collagen

Background: Bullous systemic lupus erythematosus is a generalized subepider mal blistering skin eruption in patients suffering from systemic lupus eryt hematosus. Type VII collagen was initially identified as the target antigen . Observation: We studied an unusual patient who had bullous systemic lupus e rythematosus. The patient fulfilled the criteria of systemic lupus with an antinuclear antibody titer of 1:5120. Immunopathological testing revealed i n vivo deposition of all IgG subclasses, secretory IgA1, and both light cha ins at the patient's skin basement membrane. The in vivo-bound IgG and IgA were localized at the hemidesmosomes and lamina densa. The patient's IgG an d IgA circulating autoantibodies labeled both the epidermal roof and the de rmal floor of salt-split skin and recognized the hemidesmosomal protein BP2 30 as well as the full-length native form and the recombinant noncollagenou s domain 1 of type VII collagen (anchoring fibril). In addition, the patien t's IgG autoantibodies recognized the anchoring filament proteins laminin-5 and laminin-6 (alpha 3 chain and gamma 2 chain). Conclusions: We conclude that patients with bullous systemic lupus erythema tosus may have autoantibodies to multiple basement membrane components crit ical for epidermal-dermal junctional adhesion. Possible pathogenic mechanis ms in this patient's clinical diseases include provocation of organ-specifi c disease (bullous disease) by systemic autoimmunity (lupus) and the "epito pe spreading" immune phenomenon.