Monospecific monoclonal antibodies to keratin 1 carboxy terminal (synthetic peptide) and to keratin 10 as markers of epidermal differentiation

Monospecific antibodies to individual keratin polypeptides can be used to examine the tissue and cellular coexpression of members of keratin pairs. Monospecific monoclonal and polyclonal antibodies have been raised to keratins 1 and 10 using both crude cytoskeletal extracts and synthetic peptides. The tissue distribution of these keratins has been determined against a panel of freshly frozen normal tissues from humans, rodents and pigs. Epidermal expression has been examined in psoriatic plaques, and healing wounds, as examples of epidermal hyperproliferation. Cultured keratinocytes in monolayer (low calcium), stratified (high calcium), and complex cultures, transformed keratinocytes, and tumour cell lines, have been examined for the in vitro expression of these keratins. The sensitivity and precise localization of reactivity with these monospecific antibodies gives a highly accurate picture of individual cell expression. There is confirmation of coexpression of keratins 1 and 10 in epidermal and mucosal sites, and with keratin 16 in hyperproliferative states. These monospecific antibodies provide an important means of examining keratin expression in epidermal tumours and keratinizing disorders, and of seeking keratin mutations in cell lines and in skin diseases.

Intracytoplasmic retention of type VII collagen and dominant dystrophic epidermolysis bullosa: reversal of defect following cessation of or marked improvement in disease activity

It has been recently shown that the presence of perinuclear "stellate bodies" within the epidermis in patients with a form of dominant dystrophic epidermolysis bullosa named "transient bullous dermolysis of the newborn" corresponds to collections of type VII collagen. To determine the temporal relationship of this unique immunohistochemical defect with course of clinical disease activity, we have longitudinally studied the expression of two epitopes of type VII collagen (LH 7:2; L3d) in nine patients in four such kindreds by immunofluorescence and immunoelectron microscopic technique. In every infant so studied at the time of active blistering, type VII collagen was detectable primarily within basilar and, to a lesser extent, suprabasilar keratinocytes. In contrast, type VII collagen was detectable solely in linear array along the dermoepidermal junction in skin from each patient following complete cessation or at least marked diminution of visible clinical disease activity. These findings support the hypothesis that the temporary mechanical fragility and blistering of the skin in infants with this rare subset of dominant dystrophic epidermolysis bullosa reflect the presence of reduced amounts of type VII collagen along the dermoepidermal junction, and that this diminution may be the result of either a delay in transport and integration of type VII collagen from basilar keratinocytes into the skin basement membrane or excessive phagocytosis of type VII collagen.

Three monoclonal antibodies differentiate human from murine epidermis

In order to establish a set of epidermal species markers, normal human skin, murine skin and human skin transplanted to nude mice were stained with monoclonal antibodies directed to cell membrane-bound carbohydrates, a basement membrane component and a structure in the cell nucleus. Three epidermal species markers were identified. Two markers stained exclusively human epidermis: LH7.2 detects type VII collagen and stained the basement membrane of human epidermis in unfixed frozen sections, while LP4N stained cell nuclei in human epidermis in methanol-acetone-fixed frozen sections. The third marker, HH14, stained exclusively murine epidermis. HH14 defines the histo-blood group H carbohydrate antigen and stained spinous cell membranes of murine epidermis in both frozen and formalin-fixed sections.

A porcine model using skin graft chambers for studies on cultured keratinocytes

In wound healing research, animal models permit an extensive tissue analysis which is not normally possible in clinical studies. A morphological comparison of human and porcine skin was made in order to identify those aspects of the wound healing process where a porcine model may help our understanding of clinical problems. We describe a porcine model for evaluating the growth of cultured keratinocytes on a variety of wound beds. Polytetrafluoroethylene skin graft chambers were used to isolate wounds and prevent epidermal healing from the skin edge. The chambers remained in situ for 5-7 weeks. We detail the surgical technique, the method of porcine keratinocyte culture and highlight some practical measures that were taken to optimise the "take" of the cultured keratinocyte grafts.

Restoration of basement membrane structure in pigs following keratinocyte autografting

The attachment of grafts of keratinocyte sheets is mediated in part by the presence and organisation of basement membrane components. The reappearance of basement membrane following keratinocyte autografting was examined in pigs. These studies showed that there was rapid expression of anchoring fibrils and hemidesmosomes, which reached normal numbers at 10 days. However, the length of hemidesmosomes did not reach normal size during the period of study. Weakness of attachment of keratinocyte autografted epidermis was found to lie between the basement membrane and the granulation tissue. This suggests that reported clinical problems with keratinocyte graft attachment may be mediated not only by delay in maturation of the basement membrane but also by its poor integration with collagen of the wound bed.

Kerato-dermal grafts: the importance of dermis for the in vivo growth of cultured keratinocytes

In a porcine model, we studied the benefit of dermis for the growth of cultured autologous keratinocytes (CAK) on full-thickness wounds isolated within skin graft chambers. Kerato-dermal grafts were prepared in a two stage process using autologous de-epidermalised dermis (DED) and CAK (Group 1). Control wounds were prepared by grafting either CAK only (Group 2) or DED only (Group 3). The median epidermal cover of 34 wounds in Group 1 was 47% and was significantly greater (p < 0.001) than the epidermal cover of 12 wounds in Group 2 (4%) and 14 wounds in Group 3 (12%). The epidermis in Group 1 was durable whereas it was fragile in the control wounds. Histologically rête ridges were present at 2 weeks in Group 1, but not in the control wounds. These data indicate that a dermal wound bed significantly improves the in vivo growth of cultured keratinocytes.

Patterns and composition of basement membranes in colon adenomas and adenocarcinomas

We studied the distribution of type IV collagen and type VII collagen in the basement membranes of normal mucosa of the colon, adenomas, and adenocarcinomas using immunoperoxidase and immunofluorescence techniques. In normal mucosa, we found regular type IV collagen-positive basement membranes, lining vascular structures and mucosal epithelia. These basement membranes, however, lacked type VII collagen. In adenomas of the colon, intact basement membranes were observed through type IV collagen staining. Type VII collagen staining was also detected, but only in connection with dysplastic epithelium. Adjacent to the dysplastic epithelium in adenomas, histologically normal epithelium also showed type VII collagen staining along the basement membrane, but this was restricted to the epithelium of the luminal surface. These areas were also investigated for expression of keratins 8, 18, and 19, and keratins 5 and 8 (monoclonal antibodies NCL-5D3 and RCK 102, respectively), but altered differentiation was not detected using this technique. In adenocarcinomas of the colon, type IV collagen was irregularly deposited in the basement membrane of neoplastic tubules. Type VII collagen staining was detected only in well or moderately differentiated carcinomas and in higher amounts. Our findings therefore reveal a transient expression of type VII collagen in the transition of dysplastic epithelium into carcinoma, suggesting the involvement of type VII collagen in the process of early invasion.

Skin graft storage and keratinocyte viability

The viability of human split skin grafts stored in four solutions has been assessed by monitoring the percentage of viable keratinocytes in the stored grafts. Skin grafts stored in RM+ (Ready Mix) tissue culture medium remained more viable than those stored in Hartmann's, Marshall's or saline solutions. By day 10 (postoperative), the percentage of viable keratinocytes of those grafts stored in RM+ was around 85%, compared to a value of around 10% for the other media. By day 30, RM+ achieved a value of around 60% keratinocyte viability compared to a value approaching 1% in the other storage media under investigation. RM+ provides mitogens, nutrients, growth factors and physiological pH, all of which are important factors for successful skin graft storage.

Recurrent erythema multiforme: clinical features and treatment in a large series of patients

Recurrent erythema multiforme is an uncommon disorder. We have reviewed the clinical features and treatment of 65 patients with this condition. The mean number of attacks per year was six (range 2-24), and the mean duration of the disease was 9.5 years (range 2-36) reflecting its chronicity. The majority of patients had oral mucous membrane involvement (69%). In 46 patients (71%) the condition was precipitated by a preceding herpes simplex virus infection. Acyclovir was found to be the most useful first-line treatment, with 55% of patients deriving benefit from either continuous oral acyclovir or a patient-initiated 5-day oral course at the onset of herpes simplex virus infection. Of those failing to respond to acyclovir, a small proportion responded to dapsone. The most resistant patients (11) were treated with azathioprine, with complete disease suppression in all cases.

Structural variations in anchoring fibrils in dystrophic epidermolysis bullosa: correlation with type VII collagen expression

Dystrophic epidermolysis bullosa is characterized by various abnormalities of anchoring fibrils, which are mainly composed of type VII collagen, at the dermal-epidermal junction. To define these changes more clearly, we examined skin samples from 22 patients with different forms of dystrophic epidermolysis bullosa by pre-embedding immunoelectron microscopy using an antibody (LH 7:2) that binds to the NC-1 globular domain of type VII collagen, followed by 1 nm colloidal gold-labeled secondary antibodies and subsequent silver enhancement. In dominant dystrophic epidermolysis bullosa cases, there was only a slight but variable reduction in the immunolabeling density on anchoring fibrils and on the lamina densa, in parts similar to normal human skin. In localized recessive dystrophic epidermolysis bullosa skin, some fibrillar structures just below the lamina densa (and particularly subjacent to hemidesmosomes) had specific antibody labeling despite their lack of resemblance to definitive anchoring fibrils. Immunolabeling with LH 7:2 was also seen within basal keratinocyte endoplasmic reticulum and cytoplasmic vesicles in some dystrophic epidermolysis bullosa patients, usually with milder phenotypic features. Even in the most severe cases of generalized recessive dystrophic epidermolysis bullosa, occasional immunolabeling was found within the lamina densa and on scanty thin filamentous structures at sub-lamina densa sites usually occupied by anchoring fibrils. This study suggests that dystrophic epidermolysis bullosa patients express some type VII collagen NC-1 domain epitopes that may be variably reduced at the dermal-epidermal junction or retained within basal keratinocytes. The clinical heterogeneity in dystrophic epidermolysis bullosa is mirrored by a range of immunoelectron microscopy findings, indicating variability in completeness of anchoring fibril formation and a possible spectrum of underlying type VII collagen structural protein abnormalities.

Characterization of factors involved in human papillomavirus type 16-mediated immortalization of oral keratinocytes

We have examined intrinsic and external factors that influence human papillomavirus type 16 (HPV-16)-mediated immortalization of oral keratinocytes. The efficiency with which HPV can immortalize human oral keratinocytes was quantified and a considerable difference in the transfection and immortalization competence of the cells was detected. The ability of HPV-16 to immortalize oral cells appeared to be linked to the age of the culture upon transfection. The addition of dexamethasone to the transfected cultures increased the efficiency of immortalization, possibly indicating a role for a critical level of HPV gene expression in initial outgrowth of immortalized colonies. We also document in detail the changes in the oral keratinocyte induced by HPV-16 immortalization. These include alterations associated with crisis and feeder independence as well as basic changes in keratin expression and differentiation.

The effect of backing materials on keratinocyte autograft take

A porcine model has been established to study keratinocyte autografts as a model of human keratinocyte grafting. Keratinocyte autografts were placed on 104 full thickness wounds in 13 pigs and backed with 3 dressings which varied in their ability to maintain an occlusive environment. Sixteen control wounds were ungrafted. No take was found using a backing of woven viscose and cotton gauze. Take was 20% at day 16 using a backing of woven viscose and paraffin gauze. Serial biopsies showed that keratinocytes frequently attached to the interstices of the viscose dressing and difficulty in detaching the viscose caused loss of epidermis. Hydrogel sheet backing made assessment at day 10 difficult because of wound hydration but dressing removal, enabling exudate evaporation, produced 22% take at day 13. The development of improved dressing techniques is certainly necessary for improved graft take.

A case of pretibial dystrophic epidermolysis bullosa: decreased expression of the non-helical domain of type VII collagen molecule

A 27-year-old man with an ataxic gait due to infantile cerebral paralysis exhibited recurrent blistering caused by mechanical stimuli on the pretibial area of both legs from the age of 20. His parents were not consanguineous, and he had no relatives who suffered from blistering. The histology showed a subepidermal bulla due to dermolytic epidermal-dermal separation. The anchoring fibrils were sparse and rudimentary in the predilection area. An LH 7:2 monoclonal antibody against the non-helical domain of the type VII collagen molecule stained the basement membrane zone of the patient's skin at a weaker intensity than the staining of normal human skin, but at a distinctively stronger intensity than the staining of skin from a patient with recessive dystrophic epidermolysis bullosa. Immunoelectron microscopy revealed that LH 7:2-immunoreactants were distributed irregularly within the lamina densa and sparsely in the sublamina densa region. The patient was diagnosed with pretibial dystrophic epidermolysis bullosa.

Natural history, management and complications of herpes labialis

Infection with herpes simplex virus (HSV) is a common worldwide problem. Primary infection with HSV-1 rarely causes significant problems although widespread involvement in atopic eczema can be life-threatening as may associated encephalitis. Keratoconjunctivitis, pharyngitis and hepatitis can also complicate primary infection. Twenty to 40% of the population at some stage have recurrent orolabial infections with HSV although in only 1% of these cases is this recurrence severe. Recurrent erythema multiforme appears to be associated with HSV-65% of patients are thought to have preceding herpes labialis. Many primary and recurrent infections with HSV-1 require little more than topical antiseptic therapy to control secondary infection. Systemic acyclovir, however, is indicated in various situations including complicated primary infection, infection in neonates, eczema herpeticum, HSV infections in the immunocompromised, and recurrent erythema multiforme. In the latter, prophylactic treatment with 6 months acyclovir appears to be effective.

HLA antigen frequencies in renal transplant recipients and non-immunosuppressed patients with non-melanoma skin cancer

An increased frequency of human leukocyte antigen (HLA)-DR1 was found in 49 non-immunosuppressed patients with non-melanoma skin cancer (NMSC), being highest in patients under the age of 60 with multiple squamous cell carcinomas (SCC). Of 266 patients receiving long-term immunosuppression following renal transplantation 46 (17%) were found to have NMSC. No increase in HLA-DR1 was found in renal transplant recipients (RTR) with non-melanoma skin cancer (RTR+C) when compared with matched renal transplant recipients without skin cancer (matched RTR-C), or when compared with healthy controls. There was an increased frequency of DQw2 in RTR+C, most pronounced in RTR with SCC (61.9% compared with 18.75% in matched RTR-C), giving a relative risk of 13.98. We found statistically significant differences in the frequency of a number of HLA antigens on comparing RTR+C with healthy controls, but none of these differences were found when we compared RTR+C against matched RTR-C.

Keratin expression in normal skin and epidermal neoplasms demonstrated by a panel of monoclonal antibodies

The tissue labelling of a panel of monoclonal antikeratin antibodies (LL001, LL002, LL003, LP2K, BA17, LP34, CAM5.2, and LH1) recognising keratins 1, 5, 8, 10, 14, 18, and 19 were investigated in frozen and formalin-fixed normal skin. Antibodies LL001, LL003, BA17, LP34, CAM5.2, and LH1 were found to be reactive in formalin-fixed material and were used to study 23 basal cell carcinomas, 8 squamous cell carcinomas, 5 keratoacanthomas, 5 Bowen's disease, and 6 clear cell acanthomas. All these tumours demonstrated a loss of keratin 10 expression as demonstrated by loss of labelling with LH1. Keratin 14 expression, as demonstrated by LL001, was reduced but present in all the tumours except squamous cell carcinomas and keratoacanthomas where increased labelling was observed in the more differentiated areas of these tumours. Simple epithelial keratin expression was demonstrated by positive labelling with CAM5.2 and keratin 19 by BA17 in a third of basal cell carcinomas and squamous cell carcinomas. Three of the five keratoacanthomas labelled with BA17, indicating the presence of keratin 19 in these lesions. These results support the concept that keratin expression is a phenotypic marker of the state of differentiation or malignant transformation and that patterns of keratin expression are not specific to any particular premalignant or malignant disorder.

Replication of varicella zoster virus in primary human keratinocytes

The ability of varicella zoster virus (VZV) to infect and replicate in human keratinocytes in culture was examined. Primary human keratinocytes derived from the abdomen, breast, and foreskin were plated as monolayers and infected by co-cultivation with VZV infected fibroblasts (MRC-5 cells). Replication and spread of the virus was assayed by plaque assay and immunofluorescence of infected cells using a VZV specific monoclonal antibody. Although all three types of keratinocytes tested were capable of supporting productive VZV infection, the keratinocytes showed a 1.5 to 2 log reduction in virus yield as compared to infection of monolayer cultures of MRC-5 cells. Results from immunofluorescence studies and plaque assays indicate a slower rate of cell-to-cell spread of the virus. Testing of an anti-VZV compound in this novel assay system demonstrated an interesting sensitivity compared to that observed in conventional assay systems.

Immunohistochemical localization of basement membrane type VII collagen and laminin in neoplasms of the head and neck

The distribution pattern of the basement membrane components type VII collagen and laminin, was studied immunohistochemically in normal human head and neck tissues and in a series of benign and malignant tumours from the same site. Using monoclonal antibodies, a basement membrane containing type VII collagen and laminin could be demonstrated beneath the epithelial cell layer in 16 normal head and neck tissues from different localizations. Unlike type VII collagen, laminin was also abundantly present around blood vessels and muscle fibres. With respect to 42 squamous cell carcinomas studied, type VII collagen and laminin were present in basement membranes surrounding small and large tumour fields, independent of the tumour grade. Type VII collagen was demonstrated in the cytoplasm of tumour cells in 36% of the cases, while the antibody to laminin displayed a basement membrane staining pattern mainly. Both antibodies showed a staining gradient in more than half of the cases, with strong staining in the centre of the tumour and weakening of the staining towards the tumour periphery. In a series of 22 salivary gland tumours consisting of 19 pleomorphic adenomas and three adenoid cystic carcinomas, the distribution pattern of type VII collagen and laminin was very heterogeneous. Laminin was present in 17 and type VII collagen in 10 of 19 cases of pleomorphic adenoma, mostly scattered throughout the tumour fields. In the tumours positive for type VII collagen areas with little or no positivity were also found. A correlation between type VII collagen positivity and the presence of basal cell keratin 14 positivity was noticed in the majority of cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Intracellular expression of type VII collagen during wound healing in severe recessive dystrophic epidermolysis bullosa and normal human skin

The ability of keratinocytes to synthesize basement membrane components in vivo during wound healing in normal human skin and in severe recessive dystrophic epidermolysis bullosa (RDEB) was investigated. Indirect immunofluorescence using anti-type VII collagen (VIIc, recognizing the globular non-helical component of the molecule), anti-type IV collagen, anti-laminin and bullous pemphigoid antisera, was performed on biopsies of intact skin and of healing skin taken between 7 and 14 days after dermatome injury (upper to mid-dermal wounding) in eight patients with severe RDEB and in seven normal subjects. Baseline anti-type VIIc immunofluorescence showed completely absent staining of the epidermis, dermis and dermo-epidermal junction in severe RDEB samples, and bright linear dermo-epidermal junction fluorescence in normal human skin. In 5/5 normal human skin samples taken 9-12 days post-wounding, some type VIIc expression was noted within basal cells as well as in a continuous or interrupted linear distribution at the basement membrane zone. In all the severe RDEB biopsies sampled between days 10 and 13 (5/5), anti-VIIc fluorescence was also seen with varying intensity within basal and lowermost suprabasal cells, and in one day 14 sample at the dermo-epidermal junction. Low levels of intracellular type IVc were seen in both groups, but only in those samples taken 7-9 days after injury; later biopsies showed only continuous dermo-epidermal junction staining. Linear basement membrane zone labelling with laminin and bullous pemphigoid antisera was seen in all samples in both sets of subjects, even at day 7, but there was no detectable intracellular antisera staining.(ABSTRACT TRUNCATED AT 250 WORDS)