[Humoral immune diseases: Cutaneous vasculitis and auto-immune bullous dermatoses]

Humoral immunity is the cause of multiple diseases related to antibodies (IgA, IgG, IgM) produced by the patient. Two groups of diseases are identified. The first group is related to circulating antigen-antibody complexes. The antigens are various. They are often unknown. These immune complexes cause a vascular inflammation due to the complement fixation. Consequently, this group is dominated by inflammatory vasculitis. In the second group, the pathology is due to the fixation in situ of antibodies to a target antigen of the skin that is no more recognized by the patient. This group is represented by the auto-immune bullous dermatoses.

[Epidermolysa bullosa acquisita and graft-versus-host disease]

BACKGROUND

Epidermolysis bullosa acquisita (EBA) is a rare acquired blistering disorder caused by production of auto-antibody directed against type-VII collagen. Autoimmune disorders can occur after allogenic bone marrow transplantation as manifestations associated with chronic graft-versus-host disease (GVHD). To date, there have been 10 cases reported in the literature concerning autoimmune blistering diseases following allogenic stem-cell transplants. Herein we describe a new case involving EBA.

OBSERVATION

A 46-year-old woman developed EBA 4 years after allogenic cord blood transplantation for non-Hodgkin T-cell lymphoma complicated by acute digestive and cutaneous GVHD. At physical examination, she had some cutaneous blisters on the abdomen, arms and face, as well as numerous erosions in the buccal cavity. Direct immunofluorescence microscopy revealed linear IgG and C3 deposits along the dermal-epidermal basement membrane zone. Indirect immunofluorescence showed weak IgG G4 anti-basement membrane zone antibodies, which reacted with the dermal side of 1M NaCl-split skin; the autoantibodies were directed against type-VII collagen. This second case of EBA was evocative of a GVHD blistering disease. After the therapeutic failure of dapsone and of combined mycophenolate-prednisone, treatment with rituximab proved effective.

DISCUSSION

EBA may form part of the autoimmune signs associated with chronic GVH. The destruction of basement membrane and of epidermal basal cells that occurs in GVH could give rise to autoimmune bullous disease. However, in our patient, in whom manifestation of chronic GVH was restricted to the lungs, it is difficult to rule out the fortuitous onset of EBA, which presented at a sizeable interval after acute GVH.