Epidermolysis bullosa. Clinical aspects, pathology, and recent advances in research

Nutritional outcomes in children with epidermolysis bullosa: the experiences of two centers in Korea

PURPOSE

Epidermolysis bullosa (EB) is associated with variable risks of extracutaneous manifestations and death. Currently, there is limited information on the clinical course and prognosis of EB in Korea. This study analyzed the nutritional outcomes, clinical morbidity, and mortality of children with EB.

MATERIALS AND METHODS

Thirty patients, admitted to Severance Hospital and Gangnam Severance Hospital, from January 2001 to December 2011, were retrospectively enrolled. All patients were diagnosed with EB classified by dermatologists.

RESULTS

Among the 30 patients, 5 patients were diagnosed with EB simplex, four with junctional EB, and 21 with dystrophic EB. Wound infection occurred in 47% of the patients, and blood culture-proven sepsis was noted in 10% of the patients. Two (9.2%) patients had esophageal stricture and 11 (52.4%) of the dystrophic EB patients received reconstructive surgery due to distal extremity contracture. There were five mortalities caused by sepsis, failure to thrive, and severe metabolic acidosis with dehydration. According to nutrition and growth status, most of the infants (97%) were born as appropriate for gestational age. However, at last follow-up, 56% of the children were below the 3rd percentile in weight, and 50% were below the 3rd percentile in weight for height. Sixty percent of the children had a thrive index below -3.

CONCLUSION

Postnatal growth failure is a serious problem in children with EB. Strategies to maximize nutritional support could alleviate growth failure in children with EB, and thus improve clinical outcomes.

Cause-specific risks of childhood death in inherited epidermolysis bullosa

OBJECTIVE

To determine the cause-specific risks of death in children with epidermolysis bullosa (EB).

STUDY DESIGN

Data were collected throughout the continental United States between 1986 and 2002 by the National EB Registry. The study design is cross-sectional (n = 3280), containing within it a nested randomly sampled longitudinal subcohort (n = 450).

RESULTS

The risk of death during infancy and childhood was greatest in junctional EB (JEB), with cumulative and conditional risks of 40% to 44.7% by age 1 in both JEB subtypes, rising to 61.8% in children with JEB, Herlitz subtype and 48.2% in those with JEB, non-Herlitz subtype (JEB-nH) by age 15. In decreasing order, sepsis, failure to thrive, and respiratory failure were the major causes of death in children with JEB, plateauing by age 2 to 6. A small minority of children with epidermolysis bullosa simplex, Dowling-Meara subtype was at risk for death by age 1 (cumulative risk, 2.8%), with sepsis and respiratory failure accounting for cumulative risks of 1.9% and 0.9%. Only a minority of children with recessive dystrophic epidermolysis bullosa, Hallopeau-Siemens subtype was at risk of death (cumulative risk = 8% by age 15). Renal failure also rarely accounted for death in children with JEB-nH.

CONCLUSIONS

Infants and children with inherited EB, particularly those with JEB, are at significant risk of death as a result of disease complications.

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.

The chemical composition of tooth enamel in recessive dystrophic epidermolysis bullosa: significance with respect to dental caries

Previous reports have linked the prevalence of tooth abnormalities with high caries experience in the different types of epidermolysis bullosa (EB). However, it is not known to what extent the apparent susceptibility to enamel caries is due to disease-related altered enamel chemistry in these cases. The aim of this study was to characterize the enamel of teeth from patients suffering from recessive epidermolysis bullosa dystrophica (rEBD) in terms of its mineral content, carbonate content, protein content, and amino acid composition. The results showed that dental enamel from these patients was essentially normal in terms of its chemistry. It is therefore concluded that the high caries experience in recessive dystrophic epidermolysis bullosa patients is probably related to other factors, such as compromised oral hygiene and prolonged oral clearance due to extensive oral soft tissue damage and a cariogenic diet.

Keratin 14 gene point mutation in the Köbner and Dowling-Meara types of epidermolysis bullosa simplex as detected by the PASA method

Recent advances in molecular biology have enabled the association of epidermolysis bullosa simplex (EBS) with point mutations of keratin 14 and/or keratin 5 genes to be established. We describe here the detection of point mutations in genomic DNA from formalin-fixed and paraffin-embedded sections from five cases of epidermolysis bullosa using the PCR amplification of specific alleles (PASA) method. In two of four cases of Köbner-type EBS a point mutation of helix 2b (384 Leu-Pro) was detected and in one case of Dowling-Meara-type EBS a mutation in helix 1a (125 Arg-Cys) was detected. The results of this study are consistent with previous reports and they demonstrate that the PASA method is a rapid and reproducible method for the detection of single-base changes and small deletions.

Laryngeal involvement in epidermolysis bullosa

Epidermolysis bullosa (EB) represents a group of rare hereditary mechanobullous disorders marked by blister formation following relatively minor trauma. There are three categories depending on the site of disruption within the skin: simplex (above the basement membrane), dystrophic (below the basement membrane), and junctional (at the lamina lucida). Laryngeal involvement is rare, but has been reported primarily in association with junctional EB. Presented is our experience with 5 children with EB who demonstrated laryngeal involvement. Three children required tracheostomies acutely and 1 died of airway obstruction. One patient, with the Dowling-Meara type of EB simplex, was treated conservatively with good results. Tracheostomy should be an early consideration in the management of these patients to protect the airway in the acute setting and to prevent any further laryngeal injury associated with endotracheal intubation. The rate of complications of tracheostomy appears to be low; however, the prognosis for decannulation is poor.

The National Epidermolysis Bullosa Registry

Since its inception in 1986, the NEBR has proved to be an excellent example of how a relatively small allocation of federal research funds for the development of a registry of cases of a single rare disease can have a major impact on the rapid expansion in the depth of knowledge of not only the disease itself but of a number of associated biologic principles, including keratinization and epithelial cell-extracellular matrix interactions. At present, the NEBR is generating extensive clinical, laboratory, and demographic data, both from cross-sectional and longitudinal perspectives, as well as establishing a centralized cell and tissue bank that will serve the scientific community at large as a valuable resource for future basic research on this oftentimes devastating genetic disease.

Herlitz's junctional epidermolysis bullosa is linked to mutations in the gene (LAMC2) for the gamma 2 subunit of nicein/kalinin (LAMININ-5)

We have linked Herlitz's junctional epidermolysis bullosa (H-JEB) to the gene (LAMC2) encoding the gamma 2 subunit of nicein/kalinin, an isolaminin (laminin-5) expressed by basal keratinocytes. In four H-JEB kindreds, a maximum two-point lod score of 5.33 at theta = 0 was observed between a microsatellite near LAMC2 at 1q25-31 and the disease. In one family, a homozygous point mutation leading to a premature stop codon (CGA to TGA) was identified in exon 3 of the gene. The segregation of the mutated allele implicates the mutation in the pathology of the disorder and corroborates the linkage results.

Autosomal recessive epidermolysis bullosa simplex. A case report

We report a male child with autosomal recessive epidermolysis bullosa simplex presenting at birth. The patient subsequently developed cutaneous atrophy, nail dystrophy, milia and alopecia. He had growth retardation and anaemia, but there were no other associated abnormalities. Electron microscopy showed epidermolytic cleavage. The family history indicated an autosomal recessive mode of inheritance.

Nicein (BM-600) in junctional epidermolysis bullosa: polyclonal antibodies provide new clues for pathogenic role

We have raised polyclonal antibodies against each of three subunits of the new basement membrane component nicein (formerly BM-600), the antigen recognized by the monoclonal antibody GB3 (Biochem Biophys Acta 942:45-56, 1988). Preparation of such antibodies was achieved from gel electrophoresis purification of nicein isolated by immuno-affinity chromatography. These antibodies were reactive with each transblotted denatured nicein subunit and recognized the native protein both in cultured keratinocytes and in all normal human basement membranes where the GB3 antigen is located. A reciprocal immuno-cross-reactivity was detected with the antibodies directed against the 100-kD and 150-kD (sometimes resolved as a 146-150-kD doublet) subunits of nicein, showing that they share some identical epitopes. In tissues and keratinocyte cultures from patients with the Herlitz form of junctional epidermolysis bullosa (H-JEB), GB3 is unable to recognize nicein, and the question arises whether this is due to an absence of synthesis or a structural abnormality of the protein. We report here that the polyclonal antibody directed against the 150-kD subunit of nicein binds its antigen in H-JEB patients (although usually less intensely than in control skin), whereas the other two antibodies either do not recognize or recognize only weakly their respective antigen subunits. These data suggest that nicein is present but structurally altered in basement membranes from H-JEB tissues. Furthermore, in non-Herlitz junctional and dystrophic types of epidermolysis bullosa, all three polyclonal antibodies recognize their antigens normally. Consequently, such antibodies should serve as potentially useful molecular tools for studying the expression of nicein in H-JEB.

Epidermolysis bullosa simplex, Dowling-Meara type. A report of two cases with different types of tonofilament clumping

Two cases of the Dowling-Meara type of epidermolysis bullosa simplex (EBS) are described. Both had severe blistering at birth, which improved gradually with age. Vesicles and small bullae clustering in a herpetiform fashion were seen in both cases. One showed mild pincer deformity of the nails, and in the other the nail plates were shed after subungual blistering, but regrew without deformity. Histopathology and ultrastructural study showed cytolysis of the basal cells in both cases, but ultrastructurally different forms of tonofilament clumps were present in epidermal keratinocytes. In one case there was typical round clumping of tonofilaments, and in the other a whisk-type clumping of tonofilaments. Cultured keratinocytes from the former produced round clumps of keratin filaments, but those from the latter did not. Review of previous reports of Dowling-Meara EBS revealed that cases could also be divided into two groups in terms of the type of tonofilament clumping at an ultrastructural level. The possibility of subtyping of Dowling-Meara EBS, and possible mechanisms of the blistering in this disease are discussed.

Genetic Linkage Between the Collagen VII (COL7A1) Gene and the Autosomal Dominant Form of Dystrophic Epidermolysis Bullosa in Two Dutch Kindreds

Epidermolysis bullosa is a heterogeneous group of heritable blistering skin diseases affecting epidermis and the dermal-epidermal junction zone. Recently, genetic linkage to the type VII collagen gene (Z = 8.77; theta = 0.00) localized on chromosome 3p21 was shown in three Finnish families with the autosomal dominant form of dystrophic epidermolysis bullosa. Two Dutch kindreds with intrafamilial characteristics of both the Cockayne-Touraine type and Bart's syndrome of autosomal dominant dystrophic epidermolysis bullosa have been studied. Two-point linkage analysis in these two families with the COL7A1 marker revealed a combined lod score of Z = 6.08 at theta = 0.00. These data strongly suggest that the type VII collagen gene is the candidate gene in these Dutch pedigrees. At least two (Cockayne-Touraine and Bart) of the three subtypes of dominant dystrophic epidermolysis bullosa seem to represent different forms of expression of the same gene defect.

Diagnosis and prenatal diagnosis of epidermolysis bullosa herpetiformis (Dowling-Meara) in a mother, two affected children, and an affected fetus

In utero skin biopsy was performed on a fetus at risk of an uncertain form of epidermolysis bullosa (EB). The mother had produced two affected offspring diagnosed variously as having junctional or dystrophic EB. The two offspring and the fetus were products of different fathers. The mother claimed to have no disease and on clinical examination was without blisters. Examination of the fetal skin biopsy by light and electron microscopy revealed separation of the epidermal sheet from the majority of the biopsy sample, although occasional remnants of basal cells remained associated with the basement membrane. Aggregations of keratin filaments were observed within basal cells of the detached epidermis and in the attached basal cell remnants. The diagnosis was thus suggested to be epidermolysis bullosa Dowling-Meara. Re-review of the clinical and laboratory data from the affected infants revealed a clinical and histological pattern consistent with this diagnosis. Further discussion with the mother revealed that her skin had blistered as a child and that she presently had hyperkeratotic palms and soles. This history is consistent with the autosomal dominantly inherited epidermolysis bullosa herpetiformis (Dowling-Meara). This is the first reported prenatal diagnosis of EB Dowling-Meara. The morphological criteria of intraepidermal blistering and clumped keratin filaments within basal and immediately suprabasal cells characteristic of an affected individual postnatally also identified an affected fetus. There is, however, insufficient experience to be certain that these findings will hold from region to region in the body or among all affected fetuses, and thus prenatal diagnosis on a morphological basis should still be made with caution.

Late-onset localized junctional epidermolysis bullosa and mental retardation: a distinct autosomal recessive syndrome

We present 2 sibs with a local junctional type of epidermolysis bullosa associated with enamel defect of the teeth, dystrophic nails of the feet, and mental retardation. Subluxation of the lenses was evident in 1 of them. This combination found in a brother and a sister seems to represent a distinct autosomal recessive type of epidermolysis bullosa.

The musculoskeletal manifestations of epidermolysis bullosa: an analysis of 19 cases with a review of the literature

Epidermolysis bullosa encompasses a group of rare disorders characterized by marked skin fragility and blister formation. In patients with dystrophic epidermolysis bullosa, skeletal and soft-tissue abnormalities are an important feature. An analysis of the musculoskeletal manifestations in 19 patients is presented. In the hands and feet, features included generalized osteoporosis, wedge-shaped thinning and hooking of distal phalanges, overconstricted bones, acro-osteolysis, flexion contractures, metatarsal and metacarpal subluxation, distal trophic changes, webbing of digits, encasement of the whole extremity in a pouch of skin, soft-tissue calcification and retarded skeletal maturity. Previously undescribed findings in the hands and feet are bony ankylosis of the proximal interphalangeal joints, resorption of the metatarsal and metacarpal heads, shortened metatarsal bones, carpal and tarsal fusion and destruction, and cystic changes of the distal radius and ulna. In the remainder of the skeleton, hip dysplasia with premature osteoarthritis, knee joint bony ankylosis and thoracic and thoraco-lumbar scoliosis are other undescribed findings.

Squamous cell carcinoma secondary to recessive dystrophic epidermolysis bullosa. A report of 4 patients with 17 primary cutaneous malignancies

Four patients with recessive dystrophic epidermolysis bullosa and 17 invasive primary cutaneous squamous cell carcinomas (SCCs) are presented. All skin cancers arose at the site of scarring due to recessive dystrophic epidermolysis bullosa. Three of 17 (18%) primary cutaneous SCCs recurred locally following initial treatment with either surgical excision or wide surgical excision. Patients with recessive dystrophic epidermolysis bullosa are more likely to develop SCCs of the extremities than nonimmunocompromised patients or patients with epidermodysplasia verruciformis. Like patients with epidermodysplasia verruciformis, patients with recessive dystrophic epidermolysis bullosa are likely to suffer from invasive and metastatic SCCs at a much younger age than nonimmunocompromised patients.

Junctional epidermolysis bullosa: a mild variant in two Indian sisters

Two sisters developed a bullous skin disease in early childhood. The disease had features of junctional epidermolysis bullosa but differed clinically from previously recorded variants.

Recessive dystrophic epidermolysis bullosa phenotype is preserved in xenografts using SCID mice: development of an experimental in vivo model

Recessive dystrophic epidermolysis bullosa (RDEB) is a subgroup of hereditary blistering diseases characterized by repetitive wounding and healing with subsequent extensive scarring. The purpose of this study was to establish a xenograft model that retains the RDEB phenotype and thus might be used as an experimental in vivo model to explore the molecular and biochemical mechanisms of the chronically wounded phenotype of RDEB. Full-thickness, tumor-free RDEB skin tissues were grafted onto the dorsum of severe combined immunodeficiency (SCID) mice. At 4, 8, 12, and 24 weeks after grafting, the xenografts were removed for examination. Immunofluorescence studies were performed using species-specific antibodies to human class I antigen, mouse class I antigen, human type IV and VII collagens and with cross-reacting antibody against bullous pemphigoid antigen (BPA). Staining with the antibody to human class I antigen, W6/32, and with the antibody to mouse class I antigen, 20.8.4s, confirmed the species-specific results obtained with the type IV and type VII collagen and laminin antibodies. The RDEB grafts showed essentially no staining with the type VII collagen antibody. Antibodies against laminin and BPA showed normal staining patterns in RDEB grafts. There was an overall paucity of anchoring fibrils in the grafts when examined with electron microscopy. Blisters could be induced in these grafts with minor trauma and showed a sublamina densa separation by immunomapping and electron microscopy. As late as 24 weeks post-transplantation, the RDEB grafts remain human, are not significantly replaced by mouse cells, and retain the RDEB disease phenotype.

Salivary function of persons with hereditary epidermolysis bullosa

Oral alterations of the hard and/or soft tissues are commonly associated with the different types of epidermolysis bullosa (EB). The relationship of oral soft and hard tissue changes to the disease mechanisms in different EB types remains to be elucidated. The purpose of this investigation was to evaluate selected aspects of salivary function in a healthy control population and in persons affected with different types of EB. Sixty-one patients with EB, representing all the major types of EB, and 36 unaffected persons were examined to measure their stimulated salivary flow rates and salivary levels of IgA, albumin, and total protein. Our results show that none of the types of EB demonstrated a decreased salivary flow rate. However, patients with recessive dystrophic EB had significantly elevated salivary IgA, albumin, and total protein levels. The increased IgA level seen in this form of EB appears most likely to be related to the high prevalence of oral blistering rather than the result of altered mucosal immune function. Despite severe cutaneous and extracutaneous involvement associated with inherited EB, we found no evidence to support the hypothesis of abnormal salivary function or mucosal immunity in this disease. Taken together, these findings suggest that the rampant dental caries seen in the severe forms of EB are likely attributable to nonsalivary factors such as enamel involvement, soft tissue alterations, and/or diet. Alternatively, there may be mucosal immunity or salivary enzyme alterations that influence oral disease in these patients, but these were not evaluated in this investigation.

HLA and epidermolysis bullosa: evidence for independent assortment of Weber-Cockayne subtype of epidermolysis bullosa and HLA complex

The purpose of this study was to examine the genetic linkage (but not the association) between HLA complex and Weber-Cockayne Subtype of epidermolysis bullosa (EBS-WC). We HLA typed 44 members of three multi-generation families in which 24 members have the clinical evidence of EBS-WC. The patterns of inheritance of various HLA haplotypes and the disease were mathematically analyzed to estimate frequency of recombination (i.e. genetic distance) between HLA complex and the disease by calculating Lod Scores for each family separately as well as all for three families combined. Our results show that only one family had a positive Lod Score. The Lod Scores for the remaining two families as well as the combined Lod Score for all three families were negative. These data suggest that odds are against the genetic linkage between HLA complex and Weber-Cockayne Subtype of epidermolysis bullosa and in favor of independent assortment of the disease and HLA complex.

Mutant keratin expression in transgenic mice causes marked abnormalities resembling a human genetic skin disease

To explore the relationship between keratin gene mutations and genetic disease, we made transgenic mice expressing a mutant keratin in the basal layer of their stratified squamous epithelia. These mice exhibited abnormalities in epidermal architecture and often died prematurely. Blistering occurred easily, and basal cell cytolysis was evidence at the light and electron microscopy levels. Keratin filament formation was markedly altered, with keratin aggregates in basal cells. In contrast, terminally differentiating cells made keratin filaments and formed a stratum corneum. Recovery of outer layer cells was attributed to down-regulation of mutant keratin expression and concomitant induction of differentiation-specific keratins as cells terminally differentiate, and the fact that these cells arose from basal cells developing at a time when keratin expression was relatively low. Collectively, the pathobiology and biochemistry of the transgenic mice and their cultured keratinocytes bore a resemblance to a group of genetic disorders known as epidermolysis bullosa simplex.

Revised clinical and laboratory criteria for subtypes of inherited epidermolysis bullosa. A consensus report by the Subcommittee on Diagnosis and Classification of the National Epidermolysis Bullosa Registry

Inherited epidermolysis bullosa encompasses a number of diseases, with the common finding of blister formation after minor mechanical trauma to the skin. In some forms significant, if not eventually fatal, extracutaneous disease activity may occur. In recent years application of newer technologies has contributed substantially to an overall understanding of this collection of inherited diseases. Concurrently, many new phenotypes have been recognized, in part the result of ongoing prospective patient registries in the United States and abroad. Unfortunately, this has resulted in a massive literature that may appear to be confounded by seemingly excessive or arbitrary subdivision of epidermolysis bullosa variants. With these concerns in mind a subcommittee was established by the National Epidermolysis Bullosa Registry to summarize the current literature and to make recommendations as to the best clinical and laboratory criteria for the practical diagnosis and subclassification of patients with inherited epidermolysis bullosa.

GB3 monoclonal antibody for the diagnosis of junctional epidermolysis bullosa: results of a multicenter study

GB3 monoclonal antibody detects a normal basement membrane component (GB3 antigen) that is variably expressed in junctional epidermolysis bullosa. To assess the accuracy of GB3 in the diagnosis of junctional epidermolysis bullosa, we have reviewed its use in 250 cases of the major types of epidermolysis bullosa. In the majority of cases of the simplex and dystrophic forms of epidermolysis bullosa, GB3 antigen is normally expressed. In the Herlitz variant of junctional epidermolysis bullosa, GB3 antigen expression is consistently abnormal, but in the non-Herlitz and indeterminate forms of junctional epidermolysis bullosa, 40% of cases express GB3 antigen normally. We propose that GB3 monoclonal antibody is useful in the accurate identification of patients with Herlitz junctional epidermolysis bullosa and may prove equal to electron microscopy for the diagnosis of this disease. For the non-Herlitz variants, it should not be used as an alternative to electron microscopy but may be of special value in the determination of prognosis.

Patients with severe forms of inherited epidermolysis bullosa exhibit decreased lymphokine and monokine production

Peripheral blood mononuclear cells (PBMC) from patients with severe forms of inherited epidermolysis bullosa (EB) are deficient in functions governing cellular immunity. Very low levels of interferon-gamma (IFN-gamma), interleukin-1 (IL-1), and interleukin-2 (IL-2) were produced in vitro by PBMC from patients with severe forms of EB (recessive dystrophic and dominant dystrophic) as compared to sex- and age-matched controls. Lymphokine production by PBMC from patients with junctional EB was somewhat greater than that from patients with dystrophic forms of EB but was significantly less than that from controls. The production of interferon-alpha was not found to be altered in the severe forms of EB. The PBMC from dystrophic types of EB were also deficient in production of tumor necrosis factors (TNF-alpha and TNF-beta). The degree of the reduction in immune functions was directly related to the severity of skin involvement, with recessive dystrophic EB having the lowest level of cytokine production. This reduced production of monokines and lymphokines may be partially responsible for the progression of cutaneous infections to septicemia and for the metastasis of cutaneous squamous cell carcinomas in patients with severe forms of dystrophic EB.

Squamous cell carcinoma in epidermolysis bullosa. Treatment with systemic chemotherapy

Dystrophic epidermolysis bullosa is associated with a high incidence of cutaneous squamous cell carcinoma. Despite aggressive surgical treatment, metastases occur frequently, and survival is generally poor. Chemotherapy for advanced disease has usually been avoided because of the potential for severe cutaneous toxicity. Two patients with autosomal recessive dystrophic epidermolysis bullosa and advanced squamous cell carcinoma are described. Both received cisplatin-based systemic chemotherapy without significant toxicity.

Applicability of 19-DEJ-1 monoclonal antibody for the prenatal diagnosis or exclusion of junctional epidermolysis bullosa

Recently a monoclonal antibody (19-DEJ-1) was produced with binding specificity for the mid-lamina lucida of the skin dermo-epidermal junction, in very close association with overlying hemidesmosomes. Since skin cleavage occurs within the lamina lucida in the inherited blistering disorder, junctional epidermolysis bullosa (EB), and is associated with aberrations in the morphology and/or number of hemidesmosomes in such tissue, we have sought to determine whether this monoclonal antibody could be used for prenatal diagnosis. Fetoscopy-directed skin biopsies were obtained from two fetuses at risk for junctional EB and post-mortem samples from two other fetuses with the Herlitz type of junctional EB, the latter after prenatal diagnosis by electron microscopy and termination of each pregnancy. Specimens were examined in part by light and electron microscopy for evidence of skin cleavage or other alterations in morphology, and in part by indirect immunofluorescence for altered basement membrane antigenicity. Three of four fetuses were shown to have intra-lamina lucida blister formation indicative of, and hemidesmosome hypoplasia proving, junctional EB. Each was also shown to lack expression of GB3 and 19-DEJ-1 antigens, consistent with findings noted postnatally in junctional EB; diagnosis was confirmed in each at the time of therapeutic abortion. A fourth fetus had no abnormalities detected; lack of disease involvement was confirmed at the time of delivery, and subsequently over 8 months of careful serial evaluation. We conclude that 19-DEJ-1 monoclonal antibody is an accurate and sensitive immunohistochemical probe for junctional EB, and may be employed in the prenatal diagnostic evaluation of fetuses at risk for this disorder.

Cultured epithelia from junctional epidermolysis bullosa letalis keratinocytes express the main phenotypic characteristics of the disease

Keratinocytes from a 1-week-old male infant with junctional epidermolysis bullosa letalis (JEBL) were grown in vitro and then grafted as multi-layered epithelia onto nude mice, to investigate whether the defect in the dermo-epidermal cohesiveness in the disease is of epidermal and not mesodermal origin. In culture, there was a birefringent ring of cells at the edges of the keratinocyte colonies and in places some cells looked as though they had been ejected from the periphery of the colony. At confluence, the multi-layered epithelia were easily detached from the culture flasks using only mechanical agitation. On microscopy the fully-differentiated epithelium on days 21, 30 and 40 after grafting sometimes showed blistering at the dermal-epidermal junction. No labelling was noted using a GB3 monoclonal antibody, that reacts with normal human keratinocytes in culture and with the dermo-epidermal basement membrane zone in normal skin. This indicates that the defect of JEBL may be reproduced in culture and also after grafting the cultured epithelial onto a wound without an epidermis. This suggests a possible role for the junctional structure recognized by GB3 in dermo-epidermal cohesiveness.

Chondroitin 6-sulfate proteoglycan but not heparan sulfate proteoglycan is abnormally expressed in skin basement membrane from patients with dominant and recessive dystrophic epidermolysis bullosa

Two distinct groups of proteoglycans, chondroitin 6-sulfate (C6-S) proteoglycan and heparan sulfate proteoglycan (HSPG), have been recently shown to reside within the lamina densa of normal human skin basement membrane (BM). To determine whether either or both antigens are normally expressed in one or more forms of epidermolysis bullosa (EB), a disease known to have specific alterations in skin BM, we have examined by indirect immunofluorescence 31 specimens of clinically normal skin from 28 EB patients (simplex, 5; junctional, 8; dominant dystrophic [DDEB], 9; recessive dystrophic [RDEB], 9) with monoclonal antibodies to C6-S and HSPG. HSPG was normally expressed in all EB and control skin specimens, whereas C6-S was absent along the dermoepidermal junction of 9 of 9 RDEB and 7 of 9 DDEB, and reduced in 2 of 9 DDEB cases. In contrast, C6-S was normally expressed in 5 of 5 EB simplex, 5 of 6 junctional EB, and all control skin specimens. We have subsequently extracted a greater than 400 kD C6-S proteoglycan from normal skin BM and have found that the core protein may also contain heparan sulfate side chains. Our findings suggest that 3B3 monoclonal antibody recognizes a hybrid proteoglycan in human skin, and that its absent or reduced binding in dystrophic EB skin BM may reflect either absence of associated core protein or posttranslational alterations in the proteoglycan side chains.

Epidermolysis bullosa simplex: identification of a kindred with autosomal recessive transmission of the Weber-Cockayne variety

With few exceptions, epidermolysis bullosa simplex (EBS) is transmitted as an autosomal dominant trait. All cases of autosomal recessive EBS reported to date have been associated with significant extracutaneous disease (including anemia, marked growth retardation, dentition abnormalities, and/or concurrent neuromuscular disease), early infant mortality, or often, rather extensive cutaneous involvement. In some, the cutaneous morphology has even suggested junctional or dystrophic disease. We cared for a kindred in which four individuals were affected with an autosomal recessive form of EBS with cutaneous findings most often suggestive of Weber-Cockayne disease. Except for scattered oral erosions in one patient, there was no evidence of associated extracutaneous disease. These findings demonstrate the increasing complexity of even the simplex forms of inherited epidermolysis bullosa. This obviously has implications for genetic counseling.

Abnormal organization of keratin intermediate filaments in cultured keratinocytes of epidermolysis bullosa simplex

Distinctive abnormality in the organization of keratin intermediate filaments (KIFs) was found for the first time in cultured epidermal keratinocytes from two patients with hereditary epidermolysis bullosa simplex (EBS), which showed cleavages above the basement membrane zone due to the fragility of basal cells. KIFs in EBS keratinocytes revealed an irregular radial arrangement composed of sparse but thick KIF bundles. Furthermore, these KIF bundles in many cells changed into numerous ball-like keratin aggregates and disappeared beyond these keratin aggregates in the peripheral cytoplasm. Electron microscopy of cultured EBS keratinocytes showed that many ball-like structures consisting of fine filaments or granules or homogeneous substances were scattered in the peripheral regions of the cell attaching to the dish, and intermediate filaments appeared to be emanating from or surrounding the structures. These ball-like keratin aggregates have never been observed in normal human keratinocytes.

Prenatal diagnosis of dominant and recessive dystrophic epidermolysis bullosa: application and limitations in the use of KF-1 and LH 7:2 monoclonal antibodies and immunofluorescence mapping technique

Prenatal diagnosis is now possible for junctional and recessive dystrophic forms of epidermolysis bullosa (EB); however, there is no similar published experience for dominant dystrophic EB, although data with KF-1 monoclonal antibody suggests that both forms of dystrophic EB can be identified at least postnatally with this unique probe. We now report our experience with light microscopy, electron microscopy, immunofluorescence mapping, and KF-1 and LH 7:2 monoclonal antibodies, in both a mother with dominant dystrophic EB and her fetus at risk, and in a fetus previously shown to be affected with recessive dystrophic EB. KF-1 and LH 7:2 antigens were absent in recessive dystrophic EB fetal skin, identical to findings observed postnatally. LH 7:2 was normally expressed in a mother with dominant dystrophic EB and in her fetus at risk for this disease. In contrast, while KF-1 antigen was abnormally expressed in the affected mother, it was normally expressed in only 1/7 fetal biopsies despite the fact that this fetus was shown by light and electron microscopy and immunofluorescence mapping to be unaffected with dominant dystrophic EB. We conclude that 1) transmission electron microscopy can be used to prenatally exclude the diagnosis of dominant dystrophic EB (Cockayne-Touraine variety), 2) immunofluorescence mapping is an accurate technique for prenatal as well as postnatal diagnosis of EB, and 3) KF-1 cannot by itself be used as an accurate probe for the prenatal diagnosis of dominant dystrophic EB, due to the apparent variability in the time for the normal expression of KF-1 in fetal skin during the second trimester.

Nidogen and heparan sulfate proteoglycan: detection of newly isolated basement membrane components in normal and epidermolysis bullosa skin

The epidermal basement membrane zone comprises various biochemical constituents, some of which may be affected or involved in certain forms of mechanobullous diseases. Recently, nidogen and a low density form of heparan sulfate proteoglycan--two ubiquitous, noncollagenous components of basement membranes--were isolated and characterized, and affinity-purified antibodies to each component were prepared. These antibodies were used to study the distribution of both antigens in normal and diseased human skin. By immunofluorescence, both nidogen and heparan sulfate proteoglycan were linearly distributed along the basement membrane of the dermal-epidermal junction, adnexal structures, and blood vessels of normal human skin. On suction-induced blisters of normal skin, both antigens were found at the base of the blister, indicating that each was within or below the lamina lucida. By indirect immunoelectron microscopy, both antigens were ultrastructurally located within the lamina densa. The staining patterns for nidogen and heparan sulfate proteoglycan were examined in 11 patients with either junctional, dominant dystrophic, or recessive dystrophic epidermolysis bullosa, and were found to be not different from the patterns observed in normal skin.

Autosomal dominant epidermolysis bullosa dystrophica: are the Cockayne-Touraine, the Pasini and the Bart-types different expressions of the same mutant gene?

We report on a family with autosomal dominant dystrophic epidermolysis bullosa and congenital localized absence of skin, resembling the features of Bart's Syndrome. This type of epidermolysis bullosa and the Cockayne-Touraine and Pasini types may represent different expressions of the same gene defect.

Monoclonal antibodies and the skin biopsy: current and potential clinical applications

Monoclonal antibodies are becoming increasingly useful in the clinical diagnosis and/or treatment of a number of unrelated diseases. Discussion will be directed to those monoclonal antibodies recognizing antigens within the skin which appear to have either proven or potential application in the diagnostic evaluation of the skin biopsy.