HLA and epidermolysis bullosa. Association between the HLA complex and recessive dystrophic epidermolysis bullosa

BACKGROUND AND DESIGN

--Epidermolysis bullosa refers to a group of genetic diseases characterized by marked skin fragility and blister formation following minor mechanical trauma. The patients with recessive dystrophic epidermolysis bullosa (RDEB) are the most severely affected with marked internal and external blistering, scarring, and death at an early age, secondary to malnutrition, septicemia, and/or metastatic squamous cell carcinoma. An association between RDEB and HLA antigens was explored in 28 patients with RDEB and their family members.

RESULTS

--Our data demonstrate that susceptibility to develop RDEB may be associated with the HLA complex. The gene frequencies of DR4 and DQw3 were much higher in the patients than expected. These increases were likely due to statistically significant excess of DR4 and DQw3 homozygotes in the patients. In addition, the observed frequencies of two HLA haplotypes: Bw62, DR4, DQw3 and Bw60, DR4, DQw3 were significantly higher than expected.

CONCLUSION

--If these observations are confirmed in the larger series of patients, the association between RDEB and HLA complex may have clinical utility in genetic counseling of siblings of child-bearing age who are at risk of being carriers of RDEB.

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.

Human skin basement membrane-associated heparan sulphate proteoglycan: distinctive differences in ultrastructural localization as a function of developmental age

Recent studies have demonstrated that skin basement membrane components are expressed within the dermo-epidermal junction in an orderly sequence during human foetal development. We have investigated the ultrastructural localization of basement membrane-related antigens in human foetal skin at different developmental ages using two monoclonal antibodies to a well-characterized basement membrane-associated heparan sulphate proteoglycan. A series of foetal skin specimens (range, 54-142 gestational days) were examined using an immunoperoxidase immunoelectron microscopic technique. In specimens representing very early developmental ages, very diffuse immunoreaction products were detected. However, by approximately 76 gestational days, some accentuation of heparan sulphate proteoglycan was noted along the lamina densa, and by 142 gestational days, the distribution of heparan sulphate proteoglycan was identical to that observed in neonatal and adult human skin. These findings demonstrate that active remodelling of the dermo-epidermal junction occurs during at least the first two trimesters, and affects not only basement membrane-associated structures but also specific antigens.

Immunoelectron microscopy and immunofluorescence antigenic mapping: diagnostic applications

In selected situations, direct and indirect IEM may provide important diagnostic information for the clinician, as pertains to the diagnosis and therefore prognosis in a given patient. As discussed, however, all of the more conventional approaches should be pursued before consideration is given to the performance of IEM, knowing its relative cost and technical difficulty. In contrast, we consider immunofluorescence antigenic mapping to be the diagnostic method of choice for the determination of the type of inherited EB present in affected individuals. When additional ultrastructural or morphometric data is required, then TEM can be performed as an adjunct study once it is determined by mapping technique that additional useful information may be derived.

Oral soft tissues in hereditary epidermolysis bullosa

Epidermolysis bullosa (EB) is associated with diverse oral manifestations, which can potentially involve both hard and soft tissues, depending on the specific EB subtype. This study determined the frequency and extent of oral soft tissue involvement in the inherited forms of EB. Examination of 216 affected persons revealed significant differences in the oral soft tissue involvement among the various types of EB. The frequency of oral involvement was greater in the dominant dystrophic (81.1%) and simplex (generalized, 58.6%; localized, 34.7%) types than previously reported. The marked frequency of oral blistering was similar in both major subtypes of junctional (Herlitz, 83.3%; non-Herlitz, 91.6%) and recessive dystrophic EB (generalized, 100%; localized, 92.3%). Obliteration of the oral vestibule, ankyloglossia, and microstomia were consistent findings in generalized recessive dystrophic EB. Oral milia were present in all major EB categories, most prevalently in the dystrophic forms, but were not seen in all the distinct EB subtypes. These findings indicate that although there are no pathognomonic intraoral soft tissue manifestations in the various forms of inherited EB, there are predictable patterns of involvement associated with specific subtypes of this disease. Understanding the oral involvement associated with EB may aid clinicians in the development of more advanced therapeutic approaches that are compatible with and directed at the unique characteristics of each EB subtype.

Epitope mapping of the laminin molecule in murine skin basement membrane zone: demonstration of spatial differences in ultrastructural localization

Results of studies performed to date with polyclonal antilaminin antibodies have been conflicting as to the ultrastructural localization of this glycoprotein in skin basement membrane zone (BMZ). Whereas initial reports suggested its presence solely within the lamina lucida (LL), others have suggested that laminin is instead an exclusive component of the lamina densa (LD). In an attempt to more critically address this issue, we have examined both intact and partially separated (via 1 M NaCl) murine skin BMZ by indirect immunoelectron microscopy via a two-step immunoperoxidase technique on unfixed cryopreserved tissue, utilizing nine well-characterized monoclonal antibodies with binding specificity for laminin. Localization of the sites of the epitopes recognized by these antibodies on isolated laminin molecules was previously determined by rotary shadowing and by biochemical analyses on enzymatic fragments of laminin. Whereas at least faint immunoreactants were detected in both regions with eight of nine antibodies, predominant staining was noted within the LL with three of eight and within (and even sparsely below) the LD in three of eight. One antibody bound solely to the LL; another bound equally within both regions. Although some overlap was noted, it appears that the epitope on the distal portion of the long arm of the laminin molecule resides primarily within the skin LD, whereas epitopes on more central portions of the short arms are present within the LL or within both LL and LD. The findings of stratification of laminin epitopes within skin BMZ supports a similar recent observation in mouse kidney and suggests that portions of the laminin molecule span both LD and LL, and that there may be a non-random spatial orientation for the laminin molecule within murine skin BMZ.

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.

Type VII collagen and 19-DEJ-1 antigen. Comparison of expression in inversa and generalized variants of recessive dystrophic epidermolysis bullosa

The expression of type VII collagen and 19-DEJ-1 antigen was examined in 73 and 71 patients, respectively, with recessive dystrophic epidermolysis bullosa (RDEB), comprising gravis, mitis, inversa, and indeterminant subsets, to better determine the specificity and sensitivity of two monoclonal antibodies directed against these dermoepidermal junction-specific epitopes. Type VII collagen (LH 7:2 epitope) was usually absent (in 90%) in patients with the gravis variant of RDEB, whereas its expression was most often diminished (in 67%) in those with the mitis form of the disease. Only 2% and 5% of patients with gravis and mitis variants, respectively, had apparent normal amounts of type VII collagen within their skin. In contrast, six (86%) of seven patients with the inversa variant had normal expression of the antigen. Only 25% of all patients with RDEB lacked the 19-DEJ-1 antigen; of these, however, most had the gravis variant, although absence or diminution was also infrequently observed in those with the mitis and inversa forms. Intermediate findings were noted in patients classified as having indeterminant forms of RDEB. Some variability in antigen expression was also noted among affected siblings. We conclude that assessment of expression of the LH 7:2 epitope of type VII collagen may be diagnostically useful, although considerable overlap does exist between individual patients with gravis and mitis forms. 19-DEJ-1 expression is a far less sensitive probe in RDEB, although such data may prove useful in the assessment of newborns lacking the characteristic features of gravis disease. In addition, based on our experience with inversa RDEB, it would appear that altered expression of type VII collagen cannot be attributed to blister formation in this latter rare subset, since this antigen is usually strongly detected along the dermoepidermal junction, even in perilesional skin sites.

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.

19-DEJ-1, a monoclonal antibody to the hemidesmosome-anchoring filament complex, is the only reliable immunohistochemical probe for all major forms of junctional epidermolysis bullosa

Recently, a monoclonal antibody, 19-DEJ-1, has been described with binding specificity for an epitope present within the mid-lamina lucida of the dermoepidermal junction directly underneath hemidesmosomes, suggesting recognition of a portion of the anchoring filaments. In an initial survey of specimens from patients with inherited epidermolysis bullosa (EB), it was noted that 9 of 9 specimens of Herlitz junctional EB and approximately 50% of specimens of recessive dystrophic EB lacked staining of the dermoepidermal junction with this antibody. To better define the sensitivity of binding by 19-DEJ-1 in junctional EB skin, 40 consecutive specimens representing the three major subtypes (Herlitz, 14; non-Herlitz, 15; and indeterminate, 11) were examined. No staining was noted along the dermoepidermal junction in any specimen, regardless of junctional EB subtype. Considering the recently discovered variability of binding by GB3 monoclonal antibody in some junctional EB subtypes, based on the present data it appears that the 19-DEJ-1 monoclonal antibody is the only immunohistochemical probe that can be used reliably for diagnosis of all major forms of junctional EB. Furthermore, these data suggest the possible utility of this particular antibody as a probe for identification, at the molecular level, of a basement membrane defect shared among all major forms of junctional EB.

Ultrastructural localization of the core protein of a basement membrane-specific chondroitin sulfate proteoglycan in adult rat skin

Basement membranes are complex extracellular matrices present at epithelial/mesenchymal interfaces of tissues. The dermal-epidermal junction has been shown to contain numerous components, some of the most well known being laminin, types IV and VII collagens, heparan sulfate proteoglycan, fibronectin, and entactin/nidogen. IN this paper we show, using core protein-specific antibodies, the presence of a newly described basement membrane-specific chondroitin sulfate proteoglycan at the epithelial/mesenchymal interface of adult rat skin. Ultrastructurally, this antigen was proven to reside primarily within the basal lamina, apparently concentrated in the lamina densa. In addition, some of the proteoglycan was also present beneath the lamina densa, associated with the reticular lamina collagen fibrils.

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.

Intraepidermal type VII collagen. Evidence for abnormal intracytoplasmic processing of a major basement membrane protein in rare patients with dominant and possibly localized recessive forms of dystrophic epidermolysis bullosa

Of 84 patients with dystrophic forms of epidermolysis bullosa consecutively enrolled in the National Epidermolysis Bullosa Registry, four were noted by indirect immunofluorescence with the LH 7:2 monoclonal antibody to have granular basilar keratinocyte intracytoplasmic deposits, rather than exclusively linear basement membrane deposits, of type VII collagen. Indirect immunoelectron microscopy demonstrated that these deposits were primarily perinuclear, although lesser amounts were also detectable between tonofibril bundles, within hemidesmosomes, and within and beneath the lamina densa. In two patients the mode of transmission was autosomal dominant; in two others the inheritance pattern was unknown. Whereas widespread lesions were present at birth, in each case blistering ceased within the first year of life, reminiscent of the findings in transient bullous dermolysis of the newborn. We interpret these laboratory findings as indicative of the presence of a defect in the intracytoplasmic packaging or in the transport of type VII collagen within basilar keratinocytes.

A monoclonal antibody which identifies an antigen in endothelial cell and epithelial basement membrane

We isolated a monoclonal antibody which decorates the endothelial cells of normal and lymphatic vessels in formalin-fixed, paraffin-embedded tissue. In addition, the antibody recognizes a previously undescribed substance found in the basement membrane zone and subbasement membrane zone of a variety of epithelial. By ELISA assay, the antigen recognized by this monoclonal antibody is not laminin, type IV collagen or fibronectin. This antibody may be used as a diagnostic tool because it identifies an epitope in neoplasms differentiating towards endothelial cell such as angiosarcoma and Kaposi's sarcoma.

Entactin: ultrastructural localization of an ubiquitous basement membrane glycoprotein in mouse skin

Entactin is a recently described sulfated glycoprotein component of mouse endodermal cell-derived extracellular matrix and is present in a number of basement membranes. It has been ultrastructurally localized to both lamina densa and adjacent epithelial cell membranes in rodent kidney. In the present study, we have sought to determine the localization of entactin in mouse skin. Indirect immunofluorescence and immunoelectron microscopy (the latter via immunoperoxidase technique) were performed on both intact and NaCl-separated mouse skin, using a well-characterized IgG class entactin-specific rat x mouse monoclonal antibody. At the light microscopic level, entactin was present in all skin basement membranes. On NaCl-split skin, staining was noted solely on the dermal portion. At the electron microscopic level, in intact skin, entactin was primarily localized to the lamina densa and adjacent upper papillary dermis. However, smaller amounts of immunoreaction products were also detectable within the lamina lucida and in close apposition to overlying hemidesmosomes. In partially separated skin, immunoreactants were similarly noted above the level of the lamina densa. However, in completely separated areas, hemidesmosomal or cell membrane staining was no longer visible. We conclude that entactin is an ubiquitous component of mouse skin basement membranes. Similar to previous findings in rodent kidney, entactin is present in multiple regions of skin basement membrane, although its primary localization remains within and directly beneath the lamina densa.

Autosomal recessive epidermolysis bullosa simplex. Generalized phenotypic features suggestive of junctional or dystrophic epidermolysis bullosa, and association with neuromuscular diseases

With few exceptions, epidermolysis bullosa (EB) simplex is an autosomal dominant disorder characterized by rather localized and recurrent nonscarring blister formation; mucous membranes and other organs are usually uninvolved. Recently, two patients were described with an autosomal recessive form of EB simplex associated with muscular dystrophy. We now describe four additional patients with autosomal recessive EB simplex, three of whom had associated muscular dystrophy or congenital myasthenia gravis. These patients had generalized cutaneous findings, including milia, atrophic scarring, nail dystrophy, and scalp alopecia, which have been classically attributed to either junctional or dystrophic EB. Each patient had significant oral cavity involvement, and in two, marked growth retardation and anemia were also present. Our findings suggest that autosomal recessive EB simplex may be characterized by rather severe cutaneous and extracutaneous disease activity, and may be associated with at least two distinct neuromuscular diseases.

Distribution, ultrastructural localization, and ontogeny of the core protein of a heparan sulfate proteoglycan in human skin and other basement membranes

A variety of heparan sulfate proteoglycans (HSPG) have been identified on cell surfaces and in basement membrane (BM). To more fully characterize HSPG in human skin BM, we used two monoclonal antibodies (MAb) directed against epitopes of the core protein of a high molecular weight HSPG isolated from murine EHS tumor. Indirect immunofluorescence revealed linear distribution of HSPG within all skin BM, and within BM of all other human organs investigated. In a study of the ontogeny of HSPG in human skin BM, HSPG was detectable as early as 54 gestational days, comparable with other ubiquitous BM components, such as laminin and type IV collagen. Immunoelectron microscopy on adult skin and neonatal foreskin showed staining primarily within the lamina densa (LD) and sub-lamina densa regions of the dermoepidermal junction (DEJ) and vascular BM. In neonatal foreskin, additional staining was noted of basilar cytoplasmic membranes of keratinocytes, endothelial cells, and pericytes. We conclude that the core protein of a high molecular weight HSPG is ubiquitous in human BM, appears in fetal skin on or before 54 days, and is present primarily in the regions of the LD and sub-LD.

Kindler syndrome: report of two cases and review of the literature

We evaluated two patients with hereditary bullous poikiloderma. Both had acral bullae, generalized poikiloderma with prominent atrophy, and acral keratoses. One patient, with sporadic disease, had, in addition, urethral and subglottic stenoses, webbing of digits, and poor dentition. The other patient, whose disease was dominantly inherited, had koilonychia. The results of cutaneous histopathology, electron microscopy, and immunofluorescence mapping studies are presented. It is possible that Kindler syndrome and Weary's hereditary acrokeratotic poikiloderma are variants of the same disease.

Natural killer cell activity is reduced in patients with severe forms of inherited epidermolysis bullosa

Natural killer (NK) cell activity was evaluated in 34 patients with inherited forms of epidermolysis bullosa (EB). While the NK activity of EB simplex patients did not differ from that of control subjects, persons with more severe forms of EB demonstrated significant reductions in NK activity. The degree of this reduction was directly related to the severity of the skin involvement by EB with recessive dystrophic EB patients having the lowest NK activity. The absolute number of cells bearing NK surface markers in the peripheral blood of patients with recessive dystrophic EB did not differ from that of normal control subjects. This reduced NK activity may be at least partially responsible for the occurrence of septicemia in some persons with severe forms of EB and for the development of metastatic squamous cell carcinoma in patients with dystrophic EB.