Results
Of 117 patients with BP (69 women and 48 men), anti-BP180 NC16A serum IgE was detected in 47 (40.2%) and correlated with disease activity as measured by total BPDAI (r = 0.918; P = .06). An intraindividual correlation of anti-BP180 NC16A serum levels with the total BPDAI was observed during the course of the disease in 10 randomly selected patients with BP (r = 0.983; P = .003). Although no association of circulating BP180 NC16A IgE antibodies with urticarial or erythematous lesions was observed (r = 0.481; P = .31), the presence of IgG anti-BP180 NC16A antibodies was associated with the occurrence of erosions and blisters (r = 0.985; P = .006) but not urticarial and erythematous lesions (r = 0.632; P = .23). Assaying for anti-BP180 IgE increased the diagnostic sensitivity by only 2.2% (1 of 46 serum samples) when combined with the IgG anti-BP180 enzyme-linked immunosorbent assay. Conclusions and relevance: Although detection of serum anti-BP180 IgE is not of diagnostic importance, it may be relevant for therapeutic decisions (eg, the use of anti-IgE treatment). The correlation of serum anti-BP180 NC16A IgE levels with disease activity in patients with BP supports the notion that anti-BP180 IgE is of pathogenic relevance. Our observation that IgG anti-BP180 antibodies are related to the occurrence of blisters and erosions may encourage further studies on the association of fine autoantibody reactivities with clinical features of BP.