Hereditary Epidermolysis Bullosa (EB)
Immunofluorescent (IF) mapping of a skin biopsy taken after inducing a microvesicle on normal skin is recommended as a primary diagnostic test for inherited EB (see method in biopsy sites). Reactions of antigens along the clefts helps in differentiating EB simplex, junctional EB and dystrophic EB by localizing the plane of cleavage above or below the lamina densa or in the epidermis. The absence of reactions or weak reactions with specific antibodies can point to defective proteins associated with certain forms of inherited EB.
The biopsy specimen for IF mapping studies is processed in two steps:
- Primary Screening: Primary screening for collagen types IV and VII and keratin 14 for IF mapping and biopsy suitability.
- Extended IF Mapping: For suitable biopsies, tests for plectin, alpha 6 beta 4 integrin, laminin 5, type XVII collagen, and possibly keratin 5 (if EBS).