Increased sensitivity and high specificity of indirect immunofluorescence in detecting IgG subclasses for diagnosis of bullous pemphigoid
Abstract
BackgroundIndirect 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.
AimTo determine the operating characteristics of an IgG subclass in IIF. MethodsWe 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.
ResultsThe 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%.
ConclusionDetection 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.