A novel ELISA reveals high frequencies of BP180-specific IgE production in bullous pemphigoid

Abstract

Bullous pemphigoid (BP) is a humoral autoimmune disease directed predominantly against the noncollagenous NC16A domain of the BP180 hemidesmosomal protein. Our laboratory has recently shown, using a mouse xenograft model, that passive transfer of IgE autoantibodies from BP sera induces a skin phenotype that recapitulates the early phases of the disease. Herein, we describe the development of a highly specific and sensitive ELISA to detect circulating IgE autoantibodies that recognize BP180-NC16A. Using this assay, we detect a high frequency (77%) of NC16A-specific IgE class autoantibodies in the sera of BP patients. This frequency, which is significantly higher than reported previously, is comparable to that of anti-NC16A IgG autoantibody production. In 3 BP patients monitored over time, the circulating NC16A-specific levels of both IgE and IgG were associated with clinical disease activity; however, patient sera did not always contain high levels of both isotypes. In conclusion, our ELISA provides a highly sensitive and specific tool for the detection of BP180-specific IgE in patient sera. Furthermore, we report that the majority of BP sera contain both IgE and IgG class autoantibodies specific for NC16A and suggest that screening for both isotypes of autoantibodies may provide a better diagnostic value than IgG alone.

IgE-mediated mechanisms in bullous pemphigoid and other autoimmune bullous diseases

“…[102,106] In line, serum levels of anti-NC16A IgE significantly correlated with disease severity in individual BP patients. [96,99,106,107] These data are further supported by Delaporte et al and Kalowska et al, who found the disappearance of IgE anti-BP180 autoantibodies to be associated with clinical remission. [101,102] Interestingly, in two infants with BP, no IgE reactivity against the NC16A domain was detectable.…”

“…[79] The percentage of BP patients with IgE anti-BP180 NC16A autoantibodies varied substantially in the different reports. [46,83,95,96,[99][100][101][102][103][104][105][106] In the initial report, we identified anti-BP180 NC16A IgE reactivity in 55% of 18 BP sera. [96] Subsequent studies found IgE anti-NC16A in 100% of 10, 83% of 18, 22% of 37, 77% of 43, 30% of 67, 61% of 31, and 71% of 56 BP patients.…”

FcR-Independent Effects of IgE and IgG Autoantibodies in Bullous Pemphigoid

“…This purification scheme removes 99.9% of IgG from the IgE preparation and the concentration of contaminating IgG is added to control wells. The purified autoantibodies retain their reactivity to the NC16A domain of BP180 by ELISA and bind to the BMZ of skin (18,19). Because of the difficulty in purifying sufficient amounts of IgE from controls, some experiments used a commercially available nonspecific human IgE (C IgE; Assay Designs, Ann Arbor, MI).…”

“…Within BP180, the immunodominant epitopes associated with BP have been mapped to the extracellular linker domain termed noncollagenous 16A (NC16A) (10)(11)(12)(13)(14). Approximately 90% of BP sera have both IgG and IgE class autoantibodies specific for the NC16A region of BP180 (12,(15)(16)(17)(18).…”

Our clinical experience with the use of omalizumab in the treatment of bullous pemphigoid

“…İnsan monoklonal anti-IgE otoantikoru olan omalizumab (OMZ), immün hücreler üzerinde IgE ekspresyonunu azaltarak ve IgE'nin reseptörüne bağlanmasını önleyerek mast hücreleri ve bazofiller üzerinde IgE etkisini nötralize etmiş olur 13,14 . Tedavi edilmemiş BP hastalarının çoğunda artmış dolaşan IgE seviyesi ve aynı ekstrasellüler non-kollajenöz 16A (NC16A) bölgesini esas olarak hedef alan IgE otoantikorları gösterilmiştir [15][16][17] . Geçtiğimiz yıllarda BP patomekanizmasındaki IgE'nin kritik rolünü ortaya koyan deneysel çalışmalara göre, IgE/IgE reseptör etkileşiminin inhibisyonu hastalığın tedavisinde umut verici bir tedavi seçeneği olmuştur [18][19][20][21] .…”