Diagnosis of Inherited Epidermolysis Bullosa in Resource-Limited Settings: Immunohistochemistry Revisited

Abstract

Background: Immunofluorescence (IFM) antigen mapping is the most commonly used technique to diagnose and differentiate epidermolysis bullosa (EB). In India, IFM is limited to few research laboratories and is not readily available, making the diagnosis largely clinical and often inaccurate. Ob jective of the Study: To examine the diagnostic usefulness of immunohistochemistry (IHC) as compared to IFM in resource-limited settings. Methods: Forty-four consecutive EB patients were included in this study. IHC and IFM were performed on 7-µm frozen tissue sections using standard laboratory protocols with a limited panel of antibodies. The kappa coefficient of agreement was calculated with genetic analysis as the gold standard. Results: IFM and IHC accurately identified the subtype of EB in 80.9% (p < 0.001) of the cases, when a clear blister cavity was evident on biopsy. The sensitivities and specificities of IHC and IFM for diagnosing EB simplex, junctional EB, and dystrophic EB were 100, 100, and 60% and 82.4, 100, and 100%, respectively. IHC was equally effective (p < 0.001) in establishing the type of EB as IFM. Conclusions: IHC staining and its interpretation were simple and comparable to IFM. IHC had an advantage of showing subtle changes in the epidermal architecture that could not be appreciated on IFM and hence can be considered useful in resource-limited settings.

Clinical practice guidelines for laboratory diagnosis of epidermolysis bullosa

“…The sensitivity and specificity of IFM have been compared with those of TEM or evaluated in relation to clinical diagnosis in a few case series of patients with all types of suspected EB . In only two of these studies the internal reference standard was genetic diagnosis .…”

“…IFM, also called antigen mapping, on frozen sections is a rapid technique for EB subtype diagnosis that is also feasible in resource-limited settings. 62 Variations of this technique include using different panels of antibodies or different IHC detection methods. [62][63][64][65] IHC on frozen sections is possible, 62 but it requires nearly the same equipment as IFM, excluding the need for a fluorescence microscope.…”

“…62 Variations of this technique include using different panels of antibodies or different IHC detection methods. [62][63][64][65] IHC on frozen sections is possible, 62 but it requires nearly the same equipment as IFM, excluding the need for a fluorescence microscope. In formalin-fixed, paraffin-embedded samples antigen loss is a major problem for most molecules of interest for EB diagnosis, and it is therefore not recommended.…”

Inherited Epidermolysis Bullosa – A Case Report of Several Family Members in Three Generations

“…In addition to this, in their study, Tampoia et al have suggested that the IL-6/IL-10 ratio can be used as a prognostic and predictive marker of the severity of IEB and it has been reported that this ratio is statistically higher in recessive DEB than in EBS and healthy subjects (8). Apart from immunofluorescence antigen mapping, immunohistochemistry staining could be used as a diagnostic method especially in resource-limited settings (9). Histopatho-…”

Whole Exome Sequencing Confirms Molecular Diagnostics of Three Pakhtun Families With Autosomal Recessive Epidermolysis Bullosa

“…According to the latest classification of EB, four clinical types have been defined, i.e., (a) EB simplex (EBS), (b) junctional EB (JEB), (c) dystrophic EB (DEB), and (d) Kindler syndrome ( 2 ). Clinical diagnosis is based on immunohistochemistry including skin biopsies and, electron microscopy to understand the histopathology of each EB prototype ( 3 , 4 ).…”