Increased sensitivity and high specificity of indirect immunofluorescence in detecting IgG subclasses for diagnosis of bullous pemphigoid

摘要

Summary Background Indirect immunofluorescence ( IIF ) microscopy on monkey oesophagus is an important assay for the diagnosis of bullous pemphigoid ( BP ). Its relatively low sensitivity (60–80%) may be partly due to insufficient detection of minor IgG subclasses. Aim To determine the operating characteristics of an IgG subclass in IIF . Methods We designed a retrospective, dual‐centre, controlled cohort study on sera from 64 BP sera that had been rated as false negatives by traditional IIF microscopy, and assessed circulating IgG 1 , IgG 3 and IgG 4 autoantibodies. Results The sensitivities of IIF in detecting IgG 1 , IgG 3 , IgG 4 and all three in combination were 45.3%, 18.8%, 32.8% and 48.4%, respectively. Specificities were 97%. Conclusion Detection of IgG subclass (especially IgG 1 and IgG 4 ) autoantibodies by IIF on monkey oesophagus can significantly improve diagnostic performance of IIF microscopy for diagnosis of BP .