Figure 4: Contribution of autoreactive IgE to bullous pemphigoid
pathophysiology
IgE AAb in bullous pemphigoid are directed to the intracellular
hemidesmosome protein BP230 and the transmembrane ECM-linker protein
BP180 located in the basement membrane zone (BMZ) of the skin. These
auto-IgE have a high prevalence in BP patients and share the same
epitopes with co-occurring autoreactive IgG. Crosslinking of FcεRI on
mast cells and eosinophils in skin lesions of BP patients has been
demonstrated, and anti-IgE therapy with omalizumab has been reported to
be beneficial in a small cohort of patients. However, no consistent
relationship between IgE AAb levels and disease activity in BP patients
has been established yet. Increased expression of cell-bound and soluble
IgE receptors in BP including sFcεRI and sCD23 further suggests a
complex regulatory network of IgE production.