Dear Editor
There is no doubt that the pathogenetic pathway of bullous pemphigoid (BP) is undiscovered in its whole spectrum. Literature is being enriched with further experience on combined diagnostic procedures.
In our study we used combined methods to establish diagnosis of BP in 40 patients (75.1 ± 11.8 years), 17 men and 23 women. 15 healthy volunteers and 15 patients with pemphigus vulgaris were enrolled as controls. Enrollment of patients was based on the presence of typical clinical and histological picture, as well as positive direct or indirect immunofluorescence (DIF or IIF). Blood sera were examined by BP180NC16A and BP230 ELISAs, prior to initiation of treatment.
Anti-BP180ELISA had a sensitivity of 67.5%, while sensitivity of anti-BP230 ELISA was 40%. Total sensitivity (for both antigens) was 77.5%, a value that was competitive to DIF. Specificity of anti-BP180 and anti-BP230 assay was 100%, while diagnostic accuracy was 81.4% and 65.7%, respectively. When both ELISAs were used in combination, specificity was 100% and diagnostic accuracy was 87.14%. Levels of autoantibodies were higher in patients with widespread lesions.
Atypical features do not allow clinical picture of BP to become a definite criterion. The percentage of atypical BP presentations is estimated to be around 40% 1! Joly et al, has considered significant the co-existence of four clinical criteria: age > 70 years, absence of residual scars, absence of mucosal lesions and lesions on the head and neck 2. In that study, 75% of patients had positive at least 3 out of 4 criteria 2. In our study, 77.5% of patients were positive for all clinical criteria, while 22.5% of patients had 3 out of 4.
Histological findings are diagnostic in 50-70% of cases1,3. Histology is connected to the age of lesion. Old blisters or lesions with poor inflammatory infiltrates may be misdiagnosed.
DIF is often performed in inadequate specimens, resulting in a pathology report with the conclusion "suggestive". IIF depends on the phase of BP. Chaidemenos et al, comparing clinical, histological and immunofluorescence findings, observed a variety of results without intracorrelation. The most important conclusion was that 25% of patients would have been under a wrong diagnosis if IIF was not performed 1.
Immunoblotting is a method with high potential in identifying pathogenic antigens. However, it isn't a practical method for everyday use. On the other hand, ELISA is an easy technique, able to detect specific circulating autoantibodies and quantitate their levels. Sensitivity increases with ELISAs that detect several BP180 extra or intracellular epitopes or proteins of hemidesmosomes 4.
In conclusion, combined diagnostic criteria are still needed for the diagnosis of BP.
References
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