Role of Immunofluorescence antigen mapping in the diagnosis of Epidermolysis Bullosa - A rare genetic blistering disorder

Abstract

Background: Epidermolysis Bullosa is a rare genetic mechanobullous skin and mucosal fragility with blistering. It is classified into: Epidermolysis (Simplex), lucidolytic (Junctional) and dermolytic (Dystrophic). The disease is extremely debilitating necessitating early detection and treatment. Immunofluorescence mapping is gold standard of diagnosis. Objective: To determine types and inheritance patterns of cutaneous and extracutaneous Epidermolysis Bullosa by immunofluorescence mapping. Methods: 5 µm frozen section from lesions /artificial bulla are collected over multispot PTEF coated slides. Incubation done with primary antihuman mouse antibodies (IgG) and with FITC conjugated anti-IgG mouse secondary antibodies. Antibodies used against Collagen IV, Collagen VII, cytokeratin 4, cytokeratin 14, Laminin 332, alpha6 and beta4 integrins. Healthy skin is positive control. Results: In Simplex type blister and split is above lamina densa with reduced CK14 at base (Dominant). Anti-integrins, laminin 332 and collagen IV all are present at base. In Junctional type, collagen IV present at base, cytokeratin or integrin at roof, and cleavage is at lamina lucida. Laminin 332 is reduced (dominant) or absent (recessive). In Dystrophic type blister is below lamina densa. Collagen IV or VII stains roof of blister. Collagen VII is absent in recessive type and reduced in dominant type. Limitations: Rare disease Conclusion: Agreement of clinical diagnosis and mapping is moderate indicating mapping is an essential adjunct.