Laboratory Tests for Epidermolysis Bullosa

How to take skin biopsies for epidermolysis bullosa

The definitive diagnosis of inherited epidermolysis bullosa is best made with positive immunofluorescence antigenic mapping, transmission electron microscopy, and epidermolysis bullosa-related monoclonal antibody studies. However, immunofluorescence microscopy is faster and easier as compared with electron microscopy for subtyping epidermolysis bullosa. The severity of the disease varies with the structural protein involved. A proper diagnosis should be made as soon as possible, and skin biopsies help with diagnosis. This article describes the technique of skin biopsy.

Diagnostic pitfalls in newborns and babies with blisters and erosions

Establishing the correct diagnosis in newborns presenting with blisters and erosions is not always a straightforward process. Many different disease entities including acquired (i.e., infectious, immunobullous, traumatic) and inherited disorders have to be taken into consideration. Similarities in clinical appearance, colonization and/or superinfections of preexisting skin lesions, as well as the absence of late changes in the neonate often pose significant diagnostic challenges. In this paper we discuss by giving examples the process of making an accurate diagnosis of blistering skin diseases in the neonatal period on the basis of a diagnostic algorithm. In addition, we provide an overview of the rational use and the limitations of laboratory procedures such as microbial testing, routine light microscopy, immunofluorescence antigen mapping, transmission electron microscopy, and molecular genetic analysis.

A comparative study between transmission electron microscopy and immunofluorescence mapping in the diagnosis of epidermolysis bullosa

The classification of epidermolysis bullosa (EB) into 3 main subtypes has been based on transmission electron microscopy (TEM) that is able to directly visualize and quantify specific ultrastructural features. Immunofluorescence antigenic mapping (IFM) is a technique that determines the precise level of skin cleavage by determining binding sites for a series of antibodies. To date, no study has compared the accuracy of these two techniques in diagnosing the major types of EB. A prospective cohort of 33 patients thought to have EB on clinical grounds had TEM, IFM, and genetic testing performed. The sensitivities and specificities of TEM and IFM were calculated compared with the genetic results. Of 33 cases, 30 had a positive EB diagnosis. TEM subclassified EB into its three major forms in 24/30 cases (80%) and IFM in 29/30 cases (97%). Overall, TEM sensitivities and specificities when compared with genetic results were 71% and 81%, respectively. IFM sensitivities and specificities when compared with genetic results were 97% and 100%, respectively. If a patient tested positive for EB by IFM, the likelihood ratio of having a particular type of EB was consistently greater than 20 against the reference standard (compared with a likelihood ratio less than 10 for TEM). Our results indicate that the diagnosis of EB is improved (sometimes substantially) by the use of IFM compared with TEM.

Ultrastructural differentiation of epidermolysis bullosa subtypes and porphyria cutanea tarda

Identifying subtypes of epidermolysis bullosa clinically, particularly at the time of disease onset, can be extremely difficult. In this investigation samples of intact skin from cases of epidermolysis bullosa and porphyria cutanea tarda were examined ultrastructurally and compared with normal tissue. The histological composition of the blister roof and floor surfaces was also evaluated. Three of the ten epidermolysis bullosa subtypes examined revealed specific features. Distinctive, circumscribed, clumped tonofilament bodies were present in basal keratinocytes from epidermolysis bullosa herpetiformis Dowling-Meara. Blister formation in epidermolysis bullosa simplex generalisata gravis occurred immediately above the dermo-epidermal junction aspect of stratum basale cells and thick (30 nm diameter), cross-striated anchoring fibrils were absent in epidermolysis bullosa dystrophica generalisata gravis. Features relating to the lamina densa of the dermo-epidermal junction, dermal capillaries and blister composition were distinctive, but not confined to a particular epidermolysis bullosa subtype or porphyria cutanea tarda.

Generalized gravis junctional epidermolysis bullosa: case report, laboratory evaluation, and review of recent advances

A full-term infant with junctional epidermolysis bullosa (JEB) is described. The distribution and morphologic characteristics of generalized blistering in areas of pressure in conjunction with perioral and perinasal granulation tissue suggested the diagnosis of generalized gravis (Herlitz) JEB. The family history was consistent with autosomal recessive inheritance. Electron microscopy demonstrated a subepidermal cleft arising in the lamina lucida with hemidesmosomal hypoplasia, findings consistent with gravis JEB. Immunofluorescent antigenic mapping localized laminin and type IV collagen exclusively to the blister base and weak reactivity of bullous pemphigold antigen to both the roof and the base. Type VII collagen (LH 7:2 epitope) was detected solely at the base of the cleavage plane, and abnormal staining of laminin 5 (kalinin, GB3, nicein) and 19-DEJ-1 antigen was observed. The patient died of sepsis at age 3 months. DNA extracted from cultured keratinocytes for molecular genetic analysis demonstrated a mutation with the LAMB3 gene encoding the beta 3 chain of laminin 5. We present the clinical and laboratory findings and briefly review recent advances in the diagnosis and management of JEB.

Management of patients with epidermolysis bullosa

Epidermolysis bullosa is a group of systemic disorders whose management requires familiarity with its many extracutaneous complications. These include gastrointestinal, ophthalmologic, laryngeal, dental, and hematologic problems. This article reviews wound care and management of systemic complications seen in patients with epidermolysis bullosa.