Envoplakin, a possible candidate gene for focal NEPPK/esophageal cancer (TOC): the integration of genetic and physical maps of the TOC region on 17q25

Focal nonepidermolytic palmoplantar keratoderma (NEPPK), or tylosis, is an autosomal, dominantly inherited disorder of the skin that manifests as focal thickening of the palmar and plantar surfaces. In three families studied, the skin disorder cosegregates with esophageal cancer and oral lesions. New haplotype analysis, presented here, places the tylosis esophageal cancer (TOC) locus between D17S1839 and D17S785. Envoplakin (EVPL) is a protein component of desmosomes and the cornified envelope that is expressed in epidermal and esophageal keratinocytes and has been localized to the TOC region. Mutation analysis of EVPL in the three affected families failed to show tylosis-specific mutations, and haplotype analysis of three intragenic sequence polymorphisms of the EVPL gene placed it proximal to D17S1839. Confirmation of the exclusion of EVPL as the TOC gene by location was obtained by integration of the genetic and physical mapping data using radiation hybrid, YAC, BAC, and PAC clones. This new physical map will allow further identification of candidate genes underlying NEPPK associated with esophageal cancer, which may also be implicated in the development of sporadic squamous cell esophageal carcinoma and Barrett's adenocarcinoma.

A comparison of the expression of known basement membrane components with the linear IgA disease antigens using the novel substrate cylindroma

Linear IgA disease (LAD) is characterized by IgA basement membrane zone autoantibodies. Immunofluorescence, immunoblotting and immunoelectron microscopy studies have established the complexity and heterogeneity of the target antigens. We have studied the expression of the LAD antigens by cylindroma, a benign epithelial tumour that secretes abundant basement membrane, using 57 LAD sera categorized by indirect immunofluorescence on intact and salt-split skin. The expression of known components of hemidesmosomes, the anchoring filaments, extracellular matrix and the anchoring fibrils could be differentiated and were compared with the expression of the LAD antigens. The results showed that the LAD sera bound to the cylindroma tumour in two distinctive patterns. Thirty-three sera were positive on cylindroma. Twenty-seven sera bound to the basement membrane around the tumour clusters and the islets within the clusters in a thin linear band that was occasionally discontinuous. This was similar to the pattern observed with antibodies to the hemidesmosome components, the alpha6beta4 integrin and the bullous pemphigoid antigens BP230 and BP180. This pattern was observed with sera that bound to the epidermal (11) and the dermal (3) aspects of split skin or were negative (11), and with one serum which bound only to intact skin. Seven sera, all binding to the dermal aspect of split skin, bound the tumour cluster basement membrane in a thick band that was identical in appearance to that seen with antibodies to collagen VII; however, binding to the islets was either identical to collagen VII or similar but differentiated with double staining. Some sera were negative on cylindroma. Using fluorescence overlay antigen mapping we demonstrated colocalization of some epidermal-associated LAD target antigens with known hemidesmosome proteins, and colocalization of some dermal-associated LAD target antigens with anchoring fibril components. The results using cylindroma as substrate suggest that LAD autoantibodies may react with three or more target antigens. We propose from the results of this study that the autoantibodies in LAD target multiple antigens associated with hemidesmosomes and anchoring fibrils.

N-terminal deletion in a desmosomal cadherin causes the autosomal dominant skin disease striate palmoplantar keratoderma

The N-terminal extracellular domain of the cadherins, calcium-dependent cell adhesion molecules, has been shown by X-ray crystallography to be involved in two types of interaction: lateral strand dimers and adhesive dimers. Here we describe the first human mutation in a cadherin present in desmosome cell junctions that removes a portion of this highly conserved first extracellular domain. The mutation, in the DSG1 gene coding for a desmoglein (Dsg1), results in the deletion of the first and much of the second beta-strand of the first cadherin repeat and part of the first Ca2+-binding site, and would be expected to compromise strand dimer formation. It causes a dominantly inherited skin disease, striate palmoplantar keratoderma (SPPK), mapping to chromosome 18q12.1, in which affected individuals have marked hyperkeratotic bands on the palms and soles. In a three generation Dutch family with SPPK, we have found a G-->A transition in the 3" splice acceptor site of intron 2 of the DSG1 gene which segregated with the disease phenotype. This causes aberrant splicing of exon 2 to exon 4, which are in-frame, with the consequent removal of exon 3 encoding part of the prosequence, the mature protein cleavage site and part of the first extracellular domain. This mutation emphasizes the importance of this part of the molecule for cadherin function, and of the Dsg1 protein and hence desmosomes in epidermal function.

Immunohistochemical analysis of burn depth

Clinical assessment of burns is accurate for very deep and very shallow burns, but it has been suggested that there is a high degree of inaccuracy in the assessment of dermal burns. Histologic analysis has, by some, been considered too time-consuming for routine diagnosis. It also requires an expert skin histopathologist to categorize the depth. With the use of an in vitro model, we have found the use of cryosections and an immunofluorescent staining method to be quicker and more clear-cut than standard light microscopic techniques. We believe this method plays a role in helping to define burns that would benefit from early excision and grafting. However, further investigation is required to transform the method from an experimental model to standard practice in the clinical setting.

Isolation of human tumor-specific antibodies by selection of an antibody phage library on melanoma cells

A human single-chain Fv (scFv) library as fusion to phage was constructed from donors with a high titer of autoantibodies. The library was subjected to three rounds of positive selection on human melanoma cells and negative selection on human peripheral blood mononuclear cells. Two scFv clones, B3 and B4, were isolated that bound melanoma cells in cell ELISA and fluorescence-activated cell sorting. The scFvs were characterized further by immunohistochemistry on a large number of normal human tissues. No cross-reactivity with normal tissues was observed. On the other hand, the target antigens were expressed in sections from several different melanoma patients and in some breast cancer and basal cell carcinoma sections. The unusually high tumor specificity of the B3 and B4 antigens makes them attractive targets for the specific therapy of melanoma. The selection strategy used should be generally applicable to the identification of novel cell surface antigens by antibody phage display.

Novel and recurrent mutations in keratin 10 causing bullous congenital ichthyosiform erythroderma

Bullous congenital ichthyosiform erythroderma (BCIE) is a dominantly inherited keratinizing disorder characterized by erythroderma and blistering in neonates and generalized epidermolytic hyperkeratosis (EH) in adulthood. Previously, it has been shown that BCIE can be caused by mutations in either of the genes encoding K1 or K10, the keratins predominantly expressed in suprabasal layers of the epidermis. Using direct sequencing of genomic PCR fragments, we have analyzed 4 British families with BCIE, all of whom were found to carry mutations in K10. In 1 family, the affected person was found to have an unusual dinucleotide transversion mutation, 2138CC-->AA, causing two amino acid substitutions, D155E and R156S, also in the 1A domain of the K10 polypeptide. In 2 further kindreds, the previously reported "hotspot" mutations 2139C-->T and 2140G-->A were found. These mutations predict amino acid substitutions in the helix 1A domain of K10, designated R156C and R156H respectively. The proband in the fourth family was found to carry a novel mutation 4724T-->C, predicting the amino acid change L452P in the helix 2B domain of K10. All mutations were confirmed in the affected persons and were excluded from a population of 50 normal, unrelated individuals by restriction enzyme analysis. The location of these mutations in the highly conserved helix boundary motif sequences of K10 are consistent with previously reported dominant negative mutations in K10 and other keratins. Despite the unusual nature of two of these mutations, in particular the double missense mutation, the phenotypes of the affected individuals in these 4 families were entirely typical of BCIE.

Keratin 15 expression in stratified epithelia: downregulation in activated keratinocytes

Keratin 15 (K15) is a type I keratin without a defined type II partner whose expression in epidermal diseases has not been investigated. In this study we have used LHK15, a monoclonal antibody raised against the last 17 amino acids of the K15 polypeptide, to show that K15 is expressed primarily in the basal keratinocytes of stratified tissues, including the fetal epidermis and fetal nail. Although K15 in normal hair follicles was virtually absent from hair bulbs, it was expressed by a subset of keratinocytes in the outer root sheath. By comparison, K14 expression was found throughout the outer root sheath of hair follicles; however, when both K14 alleles were naturally ablated, the expression of K15 was also observed throughout the outer root sheath of the follicles. Expression of K15 mRNA was assessed by in situ hybridization and corroborated the data from immunostaining. An increase in K15 mRNA and protein expression in hair follicles from the K14 ablated epidermis suggested an upregulation of the K15 gene in the absence of the K14 protein. In organotypical cultures where differentiating keratinocytes expressed markers of activated phenotype, i.e., K6 and K16, expression of K15 was undetectable. The expression of K15 mRNA and protein was also downregulated in two hyperproliferating situations, psoriasis and hypertrophic scars. Because keratinocytes in psoriasis and hypertrophic scars are activated, we conclude that K15 expression is not compatible with keratinocyte activation and the K15 gene is downregulated to maintain the activated phenotype.

Evidence that apoptosis and terminal differentiation of epidermal keratinocytes are distinct processes

Although there are clear parallels between apoptosis and epidermal terminal differentiation it is unclear whether terminal differentiation of keratinocytes is a form of apoptosis. We found that apoptosis was rare in adherent cultures of normal keratinocytes, even when growth factors were removed. When keratinocytes were placed in suspension for 24-96 h the majority of cells were induced to undergo terminal differentiation, as assessed by involucrin expression and cornified envelope assembly, but few cells underwent apoptosis, as assessed by morphological examination, TUNEL labelling and by DNA laddering. Withdrawal of serum and growth factors stimulated apoptosis of suspended keratinocytes but led to some reduction in the number of cells that underwent terminal differentiation. At 96 h the majority of cells retained their nuclei in the presence or absence of serum and growth factors. In normal epidermis only occasional cells within the granular layer had apoptotic nuclei, determined by TUNEL labelling and light and electron microscopy. In affected epidermis of psoriasis, Darier's disease and pityriasis rubra pilaris, diseases characterized by perturbation of growth, differentiation or adhesion, light microscopy revealed no higher proportion of apoptotic nuclei than in normal epidermis. However, the majority of viable epidermal layers in diseased skin were positive by TUNEL labelling, suggesting that TUNEL is not always a specific marker of apoptosis in keratinocytes. We conclude that in vivo and in culture keratinocyte terminal differentiation and apoptosis are distinct cellular events, subject to different stimuli.

Skin fragility and hypohidrotic ectodermal dysplasia resulting from ablation of plakophilin 1

We report a 2-year-old boy with an unusual autosomal recessively inherited skin disease comprising trauma-induced skin fragility and congenital ectodermal dysplasia affecting hair, nails and sweat glands. Skin biopsy showed widening of intercellular spaces between keratinocytes and ultrastructural findings of small, poorly formed desmosomes with reduced connections to the keratin filament cytoskeleton. Immunohistochemical analysis revealed a complete absence of staining for the accessory desmosomal plaque protein plakophilin 1 (PKP1; band 6 protein). The affected individual was a compound heterozygote for null mutations on both alleles of the PKP1 gene. Both mutations occurred within the amino terminus of PKP1, the domain which normally binds the cytoskeletal keratin filament network to the cell membrane. Apart from its localization within desmosomal plaques, PKP1 may also be present within the cytoplasm and nucleus and has putative roles in signal transduction and regulation of gene activity. The clinicopathological observations in this patient demonstrate the relevance of PKP1 to desmosome formation, cutaneous cell-cell adhesion and epidermal development and demonstrate the specific manifestations of human functional knockout mutations in this gene.

Haploinsufficiency of desmoplakin causes a striate subtype of palmoplantar keratoderma

Desmosomes are highly organized intercellular adhesive junctions that are particularly prominent in epidermis and other tissues experiencing mechanical stress. Desmoplakin, a constitutive component of the desmosomal plaque, is the most abundant protein present in such junctions and plays a critical role in linking the intermediate filament network to the plasma membrane in these tissues. Here we report the first mutation in the gene encoding desmoplakin. The identified mutation, resulting in a null allele and haploinsufficiency, was observed in genomic DNA from a kindred with the dominantly inherited skin disorder, striate palmoplantar keratoderma. Affected individuals had a linear pattern of skin thickening on the fingers and palms and circumscribed areas of skin thickening on the soles. Affected skin demonstrated loosening of intercellular connections, disruption of desmosome-keratin intermediate filament interactions and a proportion of rudimentary desmosomal structures. The disorder mapped to chromosome 6p21 with a maximum lod score of 10.67. The mutation was a heterozygous C-->T transition in exon 4 of the desmoplakin gene and predicted a premature termination codon in the N-terminal region of the peptide. This is the first reported mutation of desmo-plakin and also the first inherited skin disorder in which haploinsufficiency of a structural component has been implicated. It identifies dosage of desmoplakin as critical in maintaining epidermal integrity.

A novel human type II cytokeratin, K6hf, specifically expressed in the companion layer of the hair follicle

In an attempt to identify new members of the human type II hair keratin family by means of 3'- and 5'-RACE methods and cDNA from anagen hair follicles, we detected a sequence that encoded a hitherto unknown type II cytokeratin. The novel cytokeratin comprises 251 amino acids and exhibits the highest sequence homology with K5. Comparative one- and two-dimensional western blots of keratins from anagen hair bulbs, containing or not containing the outer and inner root sheaths (ORS/IRS), and from footsole epidermis with an antibody against the new cytokeratin, revealed its comigration with K6 and its expression in the ORS/IRS complex. We have therefore named the new cytokeratin K6hf, to distinguish it from the various K6 isoforms and to indicate its expression in the hair follicle. Both in situ hybridization with a K6hf-specific cRNA probe and indirect immunofluorescence with the K6hf antibody showed that K6hf is exclusively expressed in the so-called "companion layer" of the hair follicle, a single layered band of flat and vertically oriented cells between the cuboidal ORS cells and the IRS that stretches from the lowermost bulb region to the isthmus of the follicle. Concomitant K17 and K16 expression studies showed that besides suprabasal ORS cells, these cytokeratins are sequentially expressed subsequent to K6hf in companion cells above the hair bulb. Our study confirms the view of a vertically oriented companion layer differentiation. The clearly delayed K17 and K16 expression relative to that of K6hf in companion cells most probably excludes these keratins as possible type I partners of K6hf and suggests the existence of a still unknown type I partner of its own. Thus, not only morphologically but also biochemically, the companion layer is different from the ORS and can therefore be regarded as an independent histologic compartment of the hair follicle.

Specialized keratin expression pattern in human ridged skin as an adaptation to high physical stress

We have analysed the expression of keratins in the epidermis of normal human palm and sole skin (ridged skin) using immunohistochemistry and in situ hybridization. The epidermis of human ridged skin expresses a more complex pattern of keratins than thin skin, which is probably due to the greater stress that ridged skin has to withstand. In addition to keratin K9, we document specific expression patterns of keratins K6, K16 and K17 which are suggestive of regional adaptations of this epidermis to a high cell turnover rate. In particular, the sequestered location of nests of K17-positive cells at the bottom of the deep primary epidermal ridges supports the notion of functional heterogeneity of basal cells and suggests that the K17-positive sites may include stem cells. Expression of K6 and K16 in some basal and most suprabasal keratinocytes is compatible with a constitutively high proliferative activity of normal ridged epidermis, but may also reflect different physical properties of the suprabasal cells, in contrast with regions expressing K9. The distinct labelling patterns observed in primary and secondary epidermal ridges as well as epidermal layers above dermal papillae suggest the existence of local microenvironmental niches leading to differences in keratinocyte differentiation.

Genomic organization and fine mapping of the keratin 2e gene (KRT2E): K2e V1 domain polymorphism and novel mutations in ichthyosis bullosa of Siemens

We and others have previously shown that ichthyosis bullosa of Siemens, an autosomal dominant disorder characterized by epidermal thickening and blistering, is caused by mutations in the late-differentiation keratin K2e. Here, we have determined the genomic organization and complete sequence of the KRT2E gene, which consists of nine exons, spanning 7634 bp of DNA. The gene was mapped by high-resolution radiation-hybrid mapping to the interval between microsatellite markers D12S368 and CHLC.GATA11B02.1112. Several intragenic polymorphisms were detected, including an 18 bp duplication in exon 1, corresponding to the V1 domain of the K2e polypeptide. Genomic polymerase chain reaction conditions were optimized for all exons, and two novel mutations, N192Y in the 1A domain and E482K in the 2B domain of K2e, were found in ichthyosis bullosa of Siemens families. Mutations were excluded from 50 normal unrelated individuals by restriction analysis. These results emphasize that mutations in K2e underlie ichthyosis bullosa of Siemens and provide a comprehensive mutation detection strategy for ongoing studies of keratinizing disorders.

Basal cell carcinoma development is associated with induction of the expression of the transcription factor Gli-1

Recent work has established that activation of Hedgehog/patched signalling plays a key role in the development of basal cell carcinomas (BCCs). In Drosophila the effects of hedgehog signalling are mediated by the transcription factor Cubitus interruptus, which is homologous to the mammalian Gli family of transcription factors. In order to investigate the downstream consequences of patched gene inactivation in BCCs, we have investigated the expression of Gli-1 and Gli-3 in normal skin and BCCs by reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization. Gli-3 was found to be expressed in both normal skin and BCCs by both RT-PCR and in situ hybridization using a Gli-3-specific probe. Using a sensitive RT-PCR assay we were unable to detect Gli-1 transcripts in normal skin. Gli-1 was expressed in 13 of 14 BCCs examined, and in situ hybridization confirmed that the transcripts were localized to the epithelial component of the tumours. Our results demonstrate that inactivation of the patched gene BCCs is associated with the accumulation of Gli-1 transcripts. These findings suggest that the Gli-1 transcription factor plays a key role in BCC development.

Detection and typing of human papillomaviruses in mucosal and cutaneous biopsies from immunosuppressed and immunocompetent patients and patients with epidermodysplasia verruciformis: a unified diagnostic approach

AIM

To develop a unified diagnostic approach for the detection of human papillomavirus (HPV) DNA in skin and mucosal biopsies from both immunocompetent and immunosuppressed individuals using a degenerate polymerase chain reaction (PCR) method.

METHODS

The sensitivity and specificity of three published degenerate primer sets (HVP2/B5 and F14/B15; MY09/MY11; CP62/69 outer and CP65/68 nested primer pairs) were evaluated in PCR reactions with serial dilutions of 12 representative cloned HPV types. This combination of primers was then used to detect HPV DNA in 49 benign and malignant lesions of cutaneous and mucosal origin from immunosuppressed, immunocompetent, and epidermodysplasia verruciformis (EV) patients, and compared with detection rates using single primer sets alone.

RESULTS

The observed sensitivity of MY09/MY11 and CP62/69 + CP65/68 was high for mucosal and EV HPV types, respectively. The sensitivity of all primer sets for cutaneous types was low, but nonetheless the use of this combination of primers allowed HPV DNA detection in all of the benign warts analysed. Several mixed infections were also identified. A high prevalence of HPV DNA was similarly detected in squamous cell carcinomas from immunocompromised patients; the HPV types found were exclusively EV related.

CONCLUSIONS

The use of a combined degenerate primer PCR approach considerably improves HPV DNA detection over individual primer sets and allows detection of mixed infections. The findings may help explain the discrepancies in published reports relating to HPV DNA detection in benign and malignant skin lesions. Further modifications to this method are in progress which should significantly improve comprehensive HPV detection and typing for diagnostic purposes.

Isolation, sequence and expression of the gene encoding human keratin 13

Keratins are a family of highly homologous proteins expressed as pairs of acidic and basic forms which make intermediate filaments in epithelial cells. Keratin 13 (K13) is the major acidic keratin, which together with K4, its basic partner, is expressed in the suprabasal layers of non-cornified stratified epithelia. The mechanism which allows mucosal-specific expression of this keratin remains unknown. To provide insight into the tissue-specific expression, we have isolated the human K13 gene by screening a chromosome 17 library with a specific K13 cRNA probe. Sequence analysis of unidirectional deletions produced by transposon Tn3 has revealed that the gene is 4601 nucleotides long and contains seven introns and eight exons. When driven by the CMV promoter, the gene produced K13 protein in MCF-7 cells, which normally do not express this protein. Two transcription-start sites were identified, the major being at 61 and the minor at 63 nucleotides upstream of ATG. The upstream sequence contained a TATA box and several other putative transcription factor binding sites. A single copy of the K13 gene was detected in the human genome by Southern hybridisation and polymerase chain reaction. K13 mRNA shows differential expression in cultured keratinocytes, and in A431 cells the RNA levels remained independent of calcium concentrations in the culture medium. Characterisation of the human K13 gene will facilitate elucidation of the molecular mechanism regulating K13 expression in mucosal tissues.

Detection of human papillomavirus DNA in PUVA-associated non-melanoma skin cancers

Psoralen and UVA (PUVA) photochemotherapy is associated with a dose-dependent increased risk of nonmelanoma skin cancer in patients treated for psoriasis. Like ultraviolet B radiation, PUVA is both mutagenic and immunosuppressive and may thus act as a complete carcinogen; however, the reversed squamous to basal cell carcinoma ratio (SCC:BCC) in PUVA-treated patients, also seen in immunosuppressed renal transplant recipients, suggests a possible cofactor role for human papillomavirus (HPV) infection. In this study we examine a large series of benign and malignant cutaneous lesions for the presence of HPV DNA from patients treated with high dose (> or =500 J per cm2) ultraviolet A. A panel of degenerate primers based on the L1 (major capsid protein) open reading frame was employed, designed to detect mucosal, cutaneous, and epidermodysplasia verruciformis HPV types with high sensitivity and specificity. HPV DNA was detected in 15 of 20 (75%) non-melanoma skin cancer, seven of 17 (41.2%) dysplastic PUVA keratoses, four of five (80%) skin warts, and four of 12 (33%) PUVA-exposed normal skin samples. The majority of HPV positive lesions contained epidermodysplasia verruciformis-related HPV including HPV-5, -20, -21, -23, -24, and -38. Possible novel epidermodysplasia verruciformis types were identified in further lesions. Mixed infection with epidermodysplasia verruciformis, cutaneous, and/or mucosal types was present in six of 30 (20%) of all HPV positive lesions, including in normal skin, warts, dysplastic PUVA keratoses, and squamous cell carcinomas. The prevalence and type of HPV infection in cutaneous lesions from PUVA-treated patients is similar to that previously reported in renal transplant-associated skin lesions, and suggests that the role of HPV in PUVA-associated carcinogenesis merits further study.

Role of a p53 polymorphism in the development of human papillomavirus-associated cancer

The E6 oncoprotein derived from tumour-associated human papillomaviruses (HPVs) binds to and induces the degradation of the cellular tumour-suppressor protein p53. A common polymorphism that occurs in the p53 amino-acid sequence results in the presence of either a proline or an arginine at position 72. The effect of this polymorphism on the susceptibility of p53 to E6-mediated degradation has been investigated and the arginine form of p53 was found to be significantly more susceptible than the proline form. Moreover, allelic analysis of patients with HPV-associated tumours revealed a striking overrepresentation of homozygous arginine-72 p53 compared with the normal population, which indicated that individuals homozygous for arginine 72 are about seven times more susceptible to HPV-associated tumorigenesis than heterozygotes. The arginine-encoding allele therefore represents a significant risk factor in the development of HPV-associated cancers.

Cytokeratins in primary cutaneous amyloidosis

The expression of keratins was investigated immunohistochemically on formalin-fixed and snap-frozen primary cutaneous amyloidosis tissue with a panel of monospecific and polyspecific antikeratin antibodies, with recognized keratins K1, K5, K6, K7, K8, K10, K14, K16, K17, K18 and K19. Amyloid deposits in frozen sections of seven cases of macular amyloidosis and lichen amyloidosus always reacted with antibodies LP34 (labelling K5, K6 and K18), MNF 116 (labelling K5, K6, K8, K10, K17 and K18), and RCK 102 (labelling K5 and K8); frozen sections in one case each of the seven cases also reacted with antibodies LL001 (labelling K14), LP1K (labelling K7 and K17), and LP2K (labelling K19). In formalin-fixed sections of 13 cases of macular amyloidosis and lichen amyloidosus, amyloid deposits were labelled with LP34 in three sections, MNF 116 in four sections, LL020 (labelling keratins K5 and K6) in one section, and LP2K in two sections. In nodular primary cutaneous amyloidosis, amyloid deposits were not labelled with any antikeratin antibodies. These data confirm that amyloid in macular amyloidosis and lichen amyloidosus contains keratin epitopes, and suggests derivation of the fibrillar component from keratin intermediate filaments. Several different keratins appear to undergo conversion to amyloid. LP34, MNF 116 and RCK 102 antibodies, which have in common the labelling of keratin K5, may be useful in the diagnosis of macular and papular amyloidosis with frozen tissue sections.

Nerve and blood vessel growth in response to grafted dermis and cultured keratinocytes

The aim of this study was to study innervation and angiogenesis in response to grafts of dermis and cultured keratinocytes using immunohistochemical techniques. In a porcine model, fresh autologous de-epidermalized dermis and cultured autologous keratinocytes were combined using a two-stage technique, to produce keratodermal grafts. Wounds were encased within skin graft chambers that prevented the influence of the surrounding skin. As grafts contracted, a peripheral rim of granulation tissue became exposed, allowing us to compare the wound bed beneath grafts with that beneath the raw granulating surface. Grafts were studied for 6 weeks. Angiogenesis was studied using antisera to von Willebrand factor to detect endothelial cells. Nerve growth was studied using antisera to S-100, a Schwann cell marker, and to four axonal markers: protein gene product 9.5, C-flanking peptide of neuropeptide Y, calcitonin gene-related peptide, and vasoactive intestinal peptide. In kerato-dermal grafts (n = 28), organization of blood vessels and nerve growth occurred only beneath areas with epidermal cover as compared with the surrounding granulation tissue. Initially, the immunoreactivity to von Willebrand factor was high, but in areas with epidermal cover it assumed a more orderly pattern with fewer blood vessels. Innervation was first detected by S-100 immunoreactivity seen at 1 to 2 weeks, closely followed by that to protein gene product 9.5 and much later to calcitonin gene-related peptide. C-flanking peptide of neuropeptide Y and vasoactive intestinal peptide immunoreactivity were detected in the wound depth surrounding large blood vessels at 4 to 6 weeks. In control wounds that had been either grafted with de-epidermalized dermis alone (n = 10) or allowed to granulate (n = 10), persistently there was high immunoreactivity to von Willebrand factor but minimal immunoreactivity to the neural markers. In conclusion, kerato-dermal grafts become innervated, and beneath their surface there is also vascular organization to resemble normal skin. Keratinocytes themselves may influence angiogenesis and innervation, as both processes failed to occur beneath granulating areas.

Localisation of a gene for Papillon-Lefèvre syndrome to chromosome 11q14-q21 by homozygosity mapping

Papillon-Lefèvre syndrome is an autosomal recessively inherited palmoplantar keratoderma of unknown aetiology associated with severe periodontitis leading to premature loss of dentition. Three consanguineous families, two of Turkish and one of German origin, and three multiplex families, one of Ethiopian and two of German origin, with 11 affected and 6 unaffected siblings in all were studied. A targeted genome search was initially attempted to several candidate gene regions but failed to demonstrate linkage. Therefore a genome-wide linkage scan using a combination of homozygosity mapping and traditional linkage analysis was undertaken. Linkage was obtained with marker D11S937 with a maximum two-point lod score of Zmax = 6.1 at recombination fraction theta = 0.00 on chromosome 11q14-q21 near the metalloproteinase gene cluster. Multipoint likelihood calculations gave a maximum lod score of 7.35 between D11S901 and D11S1358. A 9.2-cM region homozygous by descent in the affected members of the three consanguineous families lies between markers D11S1989 and D11S4176 harbouring the as yet unknown Papillon-Lefèvre syndrome gene. Haplotype analyses in all the families studied support this localisation. This study has identified a further locus harbouring a gene for palmoplantar keratoderma and one possibly involved in periodontitis.