Correlation of IgE autoantibody to BP180 with a severe form of bullous pemphigoid

Objective: To determine the prevalence, immunoglobulin subclass distribution, and clinical correlation of antibodies (Abs), especially of IgE Abs, to BP180 and BP230 in patients with bullous pemphigoid (BP). Design: Retrospective case series analysis. Setting: Department of Dermatology, Nagasaki University Graduate School of Biomedical Science. Patients: Serum samples from 37 patients with BP, 6 with pemphigus vulgaris, 5 with pemphigus foliaceus, and 26 healthy controls (n=26) were examined by enzyme-linked immunosorbent assay. Main Outcome Measures: Prevalence, immunoglobulin subclass distribution, and clinical correlation of Abs, especially of IgE Abs, to BP180 and BP230. Results: IgG anti-BP180 and anti-BP230 Abs were detected in 35 (95%) and 26 (70%) of the 37 BP serum samples, respectively. IgG1 and IgG4 isotypes were positive in 32 (87%) and 25 (68%), respectively, of the BP serum samples for anti-BP180 Abs, while they were detected in 16 (44%) and 26 (70%), respectively, for anti-BP230 Abs. IgE anti-BP180 and anti-BP230 Abs were equally detected in 8 (22%) of the BP serum samples. Similar to IgG anti-BP180 Abs, the presence or levels of IgE anti-BP180 Abs was associated with broader skin lesions. Furthermore, patients with BP positive for IgE anti-BP180 Abs required longer duration for remission, higher dosage of prednisolone, and more intensive therapies for remission. By contrast, this was not true for those with of IgE anti-BP230 Abs. Remarkably, when analyzed in patients with BP who had a high titer of IgG anti-BP180 Abs, the presence or levels of IgE anti-BP180 Abs, but not IgG anti-BP180 Abs, were associated with a more severe form. Conclusions: The present study suggests that IgE anti-BP180 Abs are related to the disease severity and activity of BP. Moreover, it may be possible to identify treatment-refractory patients with BP more specifically by assessing the presence or levels of IgE anti-BP180 Abs in those with a high IgG anti-BP180 Ab titer.