Cytokeratin profiles in dyskeratosis congenita: an immunocytochemical investigation of lingual hyperkeratosis

In dyskeratosis congenita, the hyperkeratotic lesions affecting the mucous membranes have a propensity to undergo malignant change. Unfortunately there is presently no reliable method for predicting such an outcome. Oral mucosal biopsies were obtained from a case of dyskeratosis congenita and keratin expression identified using a panel of antikeratin antibodies. Marked changes were found from keratin profiles established for normal oral mucosa. In particular coexpression of three separate type 1 keratins (K16, K10 and K13) were observed in the ventral tongue lesion. The keratin pattern found in the tissue biopsies examined is suggestive of an unusually immature or disturbed state of tissue differentiation, and as such may be indicative of future malignant change.

Abnormal expression of wild type p53 protein in normal cells of a cancer family patient

Mutations in the p53 gene are the commonest specific genetic change in human cancer. In normal tissues, p53 protein is present in such low quantities that it is not readily detectable by immunochemical techniques. However, in many tumour cells large amounts of p53 protein accumulate and can be seen by simple immunohistochemical staining; this is generally attributed to the accumulation of stabilised, mutant protein. We have found a mother and daughter, who both have a history of breast cancer, who show strong immunohistochemical staining of p53 in most of their normal epithelial and mesenchymal cells. Their family has a history of multiple cancers developing at an early age. Detailed protein analysis and gene sequencing of material obtained from cultured cells, grown from a skin biopsy taken from the daughter, suggest that her cells contained large quantities of normal (unmutated) p53. We suggest that this phenotype defines a new inherited cancer susceptibility syndrome that is distinct from the germ-line mutations in p53 found in some Li-Fraumeni families. This new syndrome affects p53 tumour suppressor function through an indirect mechanism that stabilises normal p53. It remains to be established whether this mechanism also contributes to the accumulation of p53 in sporadic cancers.

Ontogenesis of the basement membrane zone after grafting cultured human epithelium: a morphologic and immunoelectron microscopic study

Sheets of cultured epithelial cells have been successfully used as autografts for the permanent coverage of patients with full-thickness burns and as allografts to stimulate the healing of chronic skin ulcers. The basement membrane zone (BMZ), composed of lamina lucida, lamina densa, and anchoring fibrils, plays a pivotal role in the firm adherence of the epidermis to the dermis. The present study describes the ultrastructural development during various stages of wound healing after resurfacing different wound areas by cultured epithelial grafts. For this purpose, biopsies were obtained from five patients 5 d to 4.5 years after resurfacing full-thickness burns with cultured autografts, and from five patients at various stages after treatment of excised tattoos and chronic skin ulcers with cultured allografts. One biopsy was taken from a spontaneously healed burn wound 30 years post-injury. Ultrathin sections were prepared for transmission and immunoelectron microscopy, using monoclonal antibodies against type IV and VII collagen. Findings were compared to controls of age- and site-matched normal skin. Eleven days after grafting, the first BMZ features had regenerated, including lamina lucida, a discontinuous lamina densa, hemidesmosomes, and sparse anchoring fibrils. The process of de novo synthesis of BMZ components had begun, and within 4 to 5 weeks complete reformation of BMZ was observed, including normal distribution of anchoring fibrils. Immunolabeling of type VII collagen was first observed upon the lower part of lamina densa at day 11 and steadily increased, reaching normal values 5 weeks after grafting. In contrast, gold deposition of type IV collagen upon lamina densa was strongly increased at day 19 compared to normal. This high expression reduced a little at 5 weeks, but remained high up to 30 years after injury. Long-term burn scars exhibited pseudopodia-like extensions of all basal cells, abundant anchoring fibrils, and an increased amount of arching anchoring fibrils. These features might compensate for the lack of proper rete ridges.

Lamina densa malformation involved in histogenesis of primary localized cutaneous amyloidosis

Skin lesions of lichenoid amyloidosis and macular amyloidosis were immunohistochemically investigated using five monoclonal antibodies against basement membrane zone (BMZ) components. A hemidesmosomal component did not contribute to amyloid deposits, but components of the lamina densa and anchoring fibrils were associated with amyloid deposits in the uppermost dermis. Immunoelectron microscopy revealed that these BMZ components were not only aggregated in the BMZ and dermis, but were also involved in the individual amyloid islets. The lamina densa was disrupted in the interface areas just above the amyloid deposits, where cytoplasm of the basal cells directly faced the aggregate of amyloid filaments. Aggregates of some BMZ components were continuous to the amyloid islets from the lamina densa area. These findings suggest that a lamina densa malformation is involved in amyloid production in the interface of the BMZ, and support the secretion theory rather than the fibrillar body theory of amyloidogenesis in these types of primary localized cutaneous amyloidosis.

Selective involvement of keratins K1 and K10 in the cytoskeletal abnormality of epidermolytic hyperkeratosis (bullous congenital ichthyosiform erythroderma)

Aggregation of tonofilaments within epidermal keratinocytes is a characteristic histologic feature of epidermolytic hyperkeratosis including the generalized form known as bullous congenital ichthyosiform erythroderma. The histologic distribution and the keratin composition of the altered tonofilaments were investigated to determine whether the aggregation was specific to any particular keratin(s). Skin samples from seven patients and one mid-trimester fetus with generalized epidermolytic hyperkeratosis, and from one patient with a localized or "nevoid" form of epidermolytic hyperkeratosis, were analyzed by using various microscopical and immunocytochemical methods. A conjunctival sample and cultured epidermal keratinocytes from one patient with generalized epidermolytic hyperkeratosis were also examined by electron microscopy and immunocytochemistry. Ultrastructurally, tonofilament aggregates were distributed within the suprabasal stratified epithelial cell layers of the epidermis, of the infundibular part of outer root sheaths, and of the sebaceous ducts and sweat ducts, selectively following the known distribution pattern of keratins K1 and K10. The abnormal tonofilaments were not found in any other cutaneous epithelia, in conjunctival epithelium, or in cultured keratinocytes, where K1 and K10 are absent or only minimally expressed. Immunoelectron microscopy showed that among the keratins detected in suprabasal epidermolytic hyperkeratosis epidermis (K1/K5/K10/K14/K16), the aggregated tonofilaments predominantly expressed K1 and K10 rather than other keratins. These results suggest that the keratin filament abnormality in epidermolytic hyperkeratosis principally involves K1 and K10 and raise the question whether epidermolytic hyperkeratosis might be primarily a disorder of one or both of these keratins.

Aberrant integrin expression during epidermal wound healing and in psoriatic epidermis

We have examined integrin expression during the remodeling of the epidermis that takes place during wound healing, using a suction blister model in which the epidermis is detached from the dermis, leaving the basement membrane intact. By immunofluorescence microscopy, we found that the same integrin subunits were expressed during wound healing as in normal epidermis with very little change in the relative intensity or distribution of staining at the leading edge of the migrating epidermis. However, at the time of wound closure, when the epidermis is still hyperproliferative, alpha 2, alpha 3, alpha 6, and beta 1 were no longer confined to the basal layer, as in normal epidermis, but were also found in all the living suprabasal cell layers, coexpressed with the terminal differentiation markers involucrin, keratin 10, and keratin 16. Strong suprabasal staining for alpha v was also found in one specimen. beta 4, which normally forms a heterodimer with alpha 6, and alpha 5 remained predominantly basal. Three of the integrin ligands, fibronectin, type IV collagen, and laminin, remained largely confined to the basement membrane zone and dermis. By 14 d after wounding, the integrins were once more restricted to the basal layer. Suprabasal integrin expression was also observed in involved psoriatic lesions. Thus, in two situations in which the epidermis is hyperproliferative, there is a failure to downregulate integrin expression on initiation of terminal differentiation. The functional consequences of this aberrant integrin expression remain to be explored.

Linkage of autosomal dominant dystrophic epidermolysis bullosa in three British families to the marker D3S2 close to the COL7A1 locus

Linkage of the anonymous marker D3S2 at 3p21 has been shown in three British families with dominant dystrophic epidermolysis bullosa with a combined lod score of 6.75 at theta = 0. This locus is close to the collagen type VII locus implying that abnormalities of this gene cause dominant dystrophic epidermolysis bullosa.

Laminin and type VII collagen distribution in different types of human lung carcinoma: correlation with expression of keratins 14, 16, 17 and 18

The expression patterns of basement membrane components and keratin intermediate filament proteins were studied in normal human bronchial epithelium and 56 lung carcinomas using monoclonal antibodies to laminin, type VII collagen and the individual keratins 14, 16, 17 and 18. In normal lung, laminin and type VII collagen were present between the epithelium and the lamina propria of bronchi and bronchioles. Keratin 14 was expressed in the basal cells, keratin 17 in the basal and some suprabasal cells and keratin 18 in the columnar cells of the bronchi and bronchioles. Keratin 16 was not present in normal bronchial epithelium. Laminin was found in all subtypes of lung carcinoma, but type VII collagen was present only in squamous cell carcinomas, where it showed a reduction in expression with decreasing differentiation. Type VII collagen was not identified in adenocarcinomas, small cell carcinomas or carcinoids. Antibodies to basal cell keratins 14 and 17 also displayed positivity only in squamous cell carcinomas, although no correlation with the degree of differentiation could be observed. Keratin 16 appeared to be a marker of the squamous phenotype, rather than of hyperproliferation. The keratin 18 marker for columnar epithelial cells showed a reaction pattern opposite to that of the basal cell keratins, being extensively present in adenocarcinomas, small cell carcinomas and carcinoids, with less expression in squamous cell carcinomas. This study shows a correlation between the presence of type VII collagen and the basal cell keratins 14 and 17, and a negative correlation between these components and keratin 18. These findings are likely to be useful in identifying lung cancer subtypes.

Changes in type I keratin expression associated with HPV16 transformation of human epidermal keratinocytes

We have used immunoblotting to compare expression of type I keratins in two strains of normal human epidermal keratinocytes (v and u) and their HPV16-transformed derivatives (vp and up). The levels of keratins 14 and 17 were similar in all four cell strains, whereas keratins 18 and 19 were more abundant in vp and up than in the normal parental keratinocytes. Keratin 13 was more abundant in the transformed cells than in the parentals; in addition, expression in v was higher than in u, and expression in vp was higher than in up, suggesting strain-specific variation in expression. Keratin 16 was the only keratin to be more highly expressed in v and u than in vp and up; this is consistent with the reduced capacity of the transformants for stratification and terminal differentiation. Double-label immunofluorescence of vp and up showed that more cells expressed involucrin than keratin 16. We conclude that HPV16 transformation results in marked changes in keratin expression. The increased expression of keratin 18, a keratin that is normally expressed in simple epithelia, fits well with reports of increased keratin 18 expression in invasive squamous cell carcinomas of skin and other keratinocyte-derived tumours.

The distribution of LH39 basement membrane epitope in the tumour stroma of oral squamous cell carcinomas

LH39 monoclonal antibody detects a novel component of epithelial and endothelial basement membranes. The expression of LH39 antigen was investigated by immunohistochemistry in 55 oral squamous cell carcinomas and compared with 15 pyogenic granulomas of skin and oral mucosa, 20 non-specific oral ulcers, and 20 specimens of normal oral mucosa. The distribution of this basement membrane epitope was compared with that of other basement membrane components, type IV collagen, and laminin. LH39 monoclonal antibody labelled basement membrane surrounding small blood vessels in normal human organs. In oral squamous cell carcinomas, in contrast to the other basement membrane antigens, the LH39 epitope was not detectable in vessels within histologically recognizable tumour stroma. Neovascularization is known to attend malignant neoplasms and this finding was interpreted as absence of LH39 antigen within newly formed vessels. In support of this hypothesis, LH39 immunoreactivity was absent in newly formed blood vessels within pyogenic granulomas and the granulation tissue within ulcers. As increasing neovascularization is reported to correlate with a rising rate of metastasis, assessment of tumour angiogenesis may be of value in selecting patients for initial aggressive therapy.

A novel lamina lucida component of epithelial and endothelial basement membranes detected by LH39 monoclonal antibody

The murine monoclonal antibody, LH39 was characterized in this study and appeared to bind to a novel basement membrane epitope. This antigen was expressed in the epithelial basement membrane of human tissue derived from all three germ cell layers and in basement membranes surrounding small blood vessels within the stroma of all organs examined. LH39 antigen could be first detected in fetal skin at the dermo-epidermal junction at 7 weeks estimated gestational age but was not present in the dermal vasculature until 16 weeks. When tested against tissue from a range of lower mammalian species, LH39 antigen appeared to be primate-specific. The epithelial basement membrane zone in organotypical cultures, where there is de novo synthesis of basement membrane components, contained abundant LH39 antigen in contrast to other basement membrane components, type IV collagen, laminin, and type VII collagen. Ultrastructural localization of LH39 epitope, using immunogold electron microscopy on unfixed freshly frozen tissue, was to the lamina lucida. No cross-reactivity could be detected between LH39 and laminin, fibronectin, and collagens I, III, IV, and V using the ELISA assay. In vitro studies with a range of proteolytic enzymes suggested that the antigen was non-collagenous in nature. LH39 precipitated a polypeptide with a molecular weight of 185 kD from extracts of metabolically labelled cultured keratinocytes, and polypeptides of 185 and 200 kD from the culture medium. The tissue distribution of LH39 antigen suggested that it may be an epitope within anchoring filaments. Potential applications of this antibody include the study of benign and malignant human vascular disorders, diseases and tumours associated with angiogenesis, epithelial neoplasms, and conditions of tissue regeneration and repair, such as wound healing.

A mutation in the conserved helix termination peptide of keratin 5 in hereditary skin blistering

In the hereditary blistering condition epidermolysis bullosa simplex, the skin blisters on trauma following rupture of epidermal basal cells. Clinical variations range from severely incapacitating, especially in early childhood, to mild forms that may not even present clinically. Dowling-Meara epidermolysis bullosa simplex is characterized by clusters of epidermal blisters and keratin clumping in the cytoplasm; recent reports describe potentially causal mutations in keratin 14 (refs 2, 3). Here we describe a 'complementary' mutation at the other end of the other keratin expressed by these cells (K5, coexpressed with K14), a change from a Glu to a Gly in the helix termination peptide, detected by altered antibody binding and confirmed by sequencing using the polymerase chain reaction. The two conserved helix boundary peptides are predicted to be essential for filament assembly, and the requirement for two complementary (type I and type II) keratins is absolute. Epidermolysis bullosa simplex diseases demonstrate the function of the keratin cytoskeleton in resisting compaction stresses which otherwise lead to cell lysis.

Keratin expression in basal cell carcinomas

The keratin phenotype of 15 cases of basal cell carcinoma was assayed immunohistochemically using a panel of monospecific antibodies to single keratin polypeptides. Whilst tumour tissue strongly expressed primary keratins 5 and 14 (normally synthesized in basal keratinocytes) no expression of secondary keratins 1 and 10 (characteristic of skin-type differentiation) was detected. Keratin 17, characteristic of the outer hair root sheath, was strongly expressed in all tumours. Keratin 19 was also normally expressed in parts of the hair follicle and was detected in four cases. The 'high cell turnover' keratin 16 was frequently induced in the overlying epidermis, but was rare within tumour tissue. No expression of simple epithelial keratins 8 and 18 was detected. Whilst the keratin phenotype of tumour cells is similar to that of basal cells within part of the hair root sheath, in keeping with suggestions of a follicular origin for basal cell carcinomas, the findings are also compatible with an origin from interfollicular pluripotent stem cells differentiating towards follicular structures.

Extensive variant of cutaneous amyloidosis: report of a case with electron-microscopic and immunohistochemical studies of the basement membrane zone at sites of amyloid production

A 60-year-old Japanese female developed widespread lichenoid eruptions with pigmentation, which initially appeared in preceding erythematous skin lesions due to dermatomyositis. Thioflavine T and Dylon stainings, electron microscopy and immunohistochemistry revealed that thick amyloid deposits were present in the papillary dermis particularly beneath the epidermis. Autopsy showed no evidence of systemic amyloidosis. Electron microscopy of the lesional skin disclosed the disturbance of lamina densa formation in the epidermal basement membrane zone (BMZ). There was disruption and dissociation of the lamina densa from the basal cell, and a lamina-densa-like substance was found in the amyloid deposits. Immunofluorescence and immunoelectron microscopy showed that type IV and VII collagens, LDA-1 antigen (a noncollagenous component of the BMZ) and laminin were distributed in irregular thick deposits along the BMZ and were also present within the amyloid itself. These findings indicate that morphological and immunohistochemical abnormalities of the lamina densa may be involved in amyloid production at the interface of the epidermis and dermis, at least in this case.

Cytokeratin expression patterns in metastatic transitional cell carcinoma of the urinary tract. An immunohistochemical study comparing local tumor and autologous metastases

The cytokeratin (CK) expression patterns of local, ie, primary or recurrent, high-grade-malignant transitional cell carcinomas (TCCs) of the human urinary tract and autologous lymphogenic and hematogenic metastases (n = 33) were compared. Special attention was paid to CK expression in the tumor invasion front and other areas where tumor-stroma interaction occurred to visualize cell populations with a metastatic phenotype. For this purpose, polypeptide-specific monoclonal antibodies to CKs 4, 7, 8, 10, 13, 14, 16, 17, 18, and 19 were used, employing the immunoperoxidase method. Results show that: 1) An increased expression of CK8 and CK18 is seen in the TCC tumor cells at the interface with peritumoral stroma in the tumor invasion front and with intratumoral stroma ('interface phenomenon'). Other than reflecting a quantitative change, this phenomenon might be explained by unmasking of CK8 and CK18 epitopes occurring in these regions. 2) Although in general the expression of CK13 in local TCC is decreased with increase of histopathologic parameters for progression, ie, grade and stage, an extensive proportion of CK13-positive tumor cells still can be found in some TCCs, even in metastases. 3) Morphologically recognizable types of aberrant differentiation in TCC, i.e., pseudosarcomatous or squamous differentiation and marked loss of differentiation, show altered expression of many of the CKs studied.

Epidermolysis bullosa simplex (Dowling-Meara type) is a genetic disease characterized by an abnormal keratin-filament network involving keratins K5 and K14

The distribution and morphology of tonofilament (TF) clumps were examined by light and electron microscopy in skin samples from a total of 17 patients with the Dowling-Meara (DM) form of epidermolysis bullosa simplex (EBS). TF clumps extending from the basal to the upper-spinous epidermal layer were seen in all lesional skin samples and in the majority of peri-lesional and non-lesional skin samples. TF clumps were also noted in adnexal epithelia, including outer hair root sheaths, sweat ducts, and sebaceous glands. Cultured keratinocytes from two patients also demonstrated characteristic TF clumps. All these epithelial cells have in common their expression of the keratin pair K5 and K14. Post-embedding immunogold electron microscopy using antibodies to K5, K14, and K10 showed similar expressed keratins in DM-EBS skin from four patients compared with normal skin, with K5 and K14 predominantly in the basal cell layer and K10 in the suprabasal layers. The clumped TF in DM-EBS samples were labeled strongly with anti-K5 and K14 antibodies in the basal and suprabasal layers. In contrast, the suprabasal clumps were only slightly reactive with anti-K10 antibodies and labeling was usually restricted to the periphery of the clumps. We conclude that DM-EBS is associated with an intrinsic abnormality of the keratin-filament network involving the K5 and K14 pair that is likely to result in impaired resistance of basal epidermal cells to external shearing forces, leading to the characteristic intraepidermal blisters. DM-EBS may become the first genetic skin disease to be recognized as having a specific keratin abnormality.

The clinical expression of bullous pemphigoid is not determined by the specificity of the target antigen

The major bullous pemphigoid (BP) antigen is a 220-240-kDa polypeptide, although some BP sera recognize bands of 180-200 kDa or lower molecular weight. We have investigated to what extent this heterogeneity of the target antigen accounts for the clinical diversity of BP. Immunoblotting studies against extracts of salt-separated epidermis were performed on sera from 39 patients with BP. The blotting patters obtained were correlated with the clinical findings, with particular reference to prodromal itching, lesion morphology and severity, mucosal involvement, presence of milia, dapsone responsiveness and disease duration. The results confirm that the major BP antigen is a 220-kDa polypeptide, and that the 180-kDa polypeptide is a second and sometimes the sole BP antigen identified in immunoblots. Rarely, multiple bands of lower molecular weight were found. There was no correlation between the pattern of BP antigens detected in immunoblots and the clinical presentation and course of BP. There was considerable clinical diversity even among the nine patients showing specificity for a single 220-kDa target antigen. Although two patients with a single 180-kDa antigen specificity had a disease of unusually long duration, factors other than antigen specificity must determine the clinical expression of BP.

Expression of simple epithelial keratins 8 and 18 in epidermal neoplasia

A systematic study of keratin expression in epidermal lesions (six actinic keratoses, 10 Bowen's disease, seven squamous cell carcinomas) has been undertaken by using a large panel of monospecific monoclonal antibodies to individual keratins. Expression of differentiation-specific keratins was frequently delayed or lost from dysplastic regions. Novel expression of the embryonic, or simple epithelial, keratins 8 and 18 was widely observed in intradermal areas of poorly differentiated squamous cell carcinomas. In addition, the most proliferative of in situ malignancies (Bowen's disease) also contained small numbers of cells expressing simple epithelial keratins. These observations suggest that the expression of simple epithelial keratins may be of functional importance in malignancy of keratinocytes and could be related to tumor invasion and/or to changes in epithelial-mesenchymal interactions.

Lichen planus pemphigoides: its relationship to bullous pemphigoid

Clinical and immunopathological studies of three patients with lichen planus pemphigoides (LPP) were carried out to investigate the relationship between LPP and bullous pemphigoid (BP) and to determine whether the antigen in LPP is the classical BP antigen. LPP is usually considered to be the coexistence of lichen planus with BP. The bullae in LPP were subepidermal and indistinguishable from BP. Indirect immunofluorescence demonstrated antibody binding to the epidermal surface of 1 M NaCl-split skin and mucosae, as in BP. The tissue distribution of the LPP antigen mirrored the distribution of BP in stratified squamous epithelia but was absent from transitional epithelia (pig bladder). Immunoelectron microscopy, both direct (two cases) and indirect (one case), showed binding to the lamina lucida as with BP antigen. Western blotting of epidermal extracts using the patients' sera showed that instead of reacting with the classical bullous pemphigoid antigen (220 kDa in our series), the antisera reacted with a unique band of 200 kDa in addition to the band of 180 kDa found as a minor antigen in bullous pemphigoid, but more commonly in pemphigoid gestationis. The relationship between these antigens awaits molecular characterization. These findings suggest that the target antigen in LPP may be unique.

Oesophageal webs preceding carcinoma and rupture of the oesophagus in cicatricial pemphigoid

A case in which oesophageal webs preceded the development of carcinoma and rupture of the oesophagus in a 77-year-old woman with cicatricial pemphigoid is reported. Oesophageal webs in cicatricial pemphigoid have been reported but are rare. Clinical, histological, radiological and post-mortem features are described. Western immunoblotting of serum demonstrated a 180-kDa antigen which comprises one of the antigens reported in cicatricial pemphigoid.

Autologous keratinocyte grafting: a new technique for intra-oral reconstruction

Oral keratinocytes have been grown in sheets in the laboratory from small oral biopsies from four patients undergoing reconstructive oral surgery. These sheets have been successfully applied to mucosal surfaces and good clinical results obtained, with accelerated healing of mucosal defects. These results indicate that keratinocyte grafts can be used in mucosal sites, and may have applications as an alternative to skin grafts in the mouth.