P68: THE PATHOGENIC ROLE OF AUTOREACTIVE IGE IN BULLOUS PEMPHIGOID: A UNIQUE CASE SUPPORTING CONCLUSIONS FROM EXPERIMENTAL DATA

Abstract

Bullous pemphigoid (BP), a blistering dermopathy, is a prototypic antibody‐mediated disease. Detection of IgG autoantibodies against hemidesmosomal proteins BP180 and/or BP230 are diagnostic and levels correlate with disease activity. Therapies include corticosteroids and oral immunosuppressants, while intravenous immunoglobulin (IVIG) and rituximab are reserved for resistant cases. These observations together support a central role for B cells and autoreactive IgG in BP pathogenesis. We describe a patient with persistent biopsy‐proven severe BP on a background of stable HIV infection with long‐term viral suppression and normal CD4 T cell counts, type 2 diabetes and chronic renal failure. The disease was widespread and refractory to standard first line therapy, IVIG and also rituximab, despite peripheral B cell depletion. Use of the monoclonal anti‐IgE antibody omalizumab resulted in a rapid resolution, within days, of pruritis and bullae formation. Disease remission has been maintained with ongoing Omalizumab therapy despite persistent high level junctional anti‐skin IgG antibodies. To our knowledge this is the first case of BP responsive to omalizumab after failure of rituximab to be described in the literature. Omalizumab does not currently have an established role in treatment of BP, although this case adds to previous case reports suggesting a role for omalizumab as a novel BP treatment. This is also supported by recent experimental data demonstrating a role for autoreactive IgE in bullous formation and correlation with disease activity. Selection of patients with BP who would benefit from anti‐IgE therapy remains to be defined, although given the speed of response and the low risk associated with its use, a therapeutic trial may be warranted in severe and/or resistant cases, particularly to reduce the side‐effects of standard therapies.