Nosocomial Staphylococcal scalded skin syndrome caused by intra-articular injection.

BACKGROUND: The pathogenic role of nasal carriage as a source for cutaneous and soft-tissue Staphylococcus aureus (SA) infections, and Staphylococcal scalded skin syndrome (SSSS) in particular, is unclear. OBSERVATION: We herein describe a nosocomial outbreak of SSSS in three orthopaedic patients who received intra-articular injections by a single orthopaedic surgeon. Bacteriological samples from the index patients and medical personnel involved in their care were assessed by phage typing, polymerase chain reaction for exfoliative toxin genes, SmaI macro-restriction analysis and molecular spa-typing. These studies first revealed SA cultural growth in synovial fluid of all three patients as well as nasal mucosa of one medical assistant. Moreover, all SA isolates had the same phage typing and antibiotic susceptibilities and were positive for exfoliative toxin ETa by polymerase chain reaction. SmaI macro-restriction and spa-typing further confirmed all proband isolates to be identical. CONCLUSION: These findings provide evidence that SA nasal colonization of otherwise healthy carriers is a risk factor for SA infections, including SSSS, in predisposed individuals.

Role of immunofluorescence microscopy in dermatology.

This paper gives a survey about most of the dermatological and infectious cutaneous diseases in which immunofluorescence (IF) microscopy is an important, often decisive tool to reach diagnosis. In tabular form, bullous autoimmune disorders such as pemphigus and pemphigoid diseases, connective tissue diseases, vasculitides, mechanobullous disorders and cutaneous infectious agents and the respective IF findings are listed. Different IF methods and especially important aspects such as taking a biopsy at the right spot or how to send samples are described. Clinical pictures of a broad spectrum of cutaneous diseases are set in combination with the IF microscopic results and the value of special but still routine investigations such as the salt split skin test (SSST) or the antigen mapping (AM) method is demonstrated especially in a set of identical or atypical clinical pictures. Immunofluorescence microscopy has not lost it´s value and should be performed in each dermatological centre in the sense of "Do not miss a diagnosis by not performing IF!"

Serum amyloid P component binds to cell nuclei in vitro and to in vivo deposits of extracellular chromatin in systemic lupus erythematosus.

Serum amyloid P component (SAP) is the single plasma protein that, from the milieu of whole normal human serum, undergoes specific calcium-dependent binding to isolated DNA and chromatin in vitro. We now report for the first time that SAP in whole serum also undergoes calcium-dependent binding to nuclei of epidermal cells in sections of normal human skin and to nuclei of fixed Hep-2 cells, a human epithelial cell line. Furthermore, and most importantly, SAP was detected in association with unusual globular dermal deposits of nuclear material in skin biopsies from two patients with systemic lupus erythematosus. This is the first evidence for binding of SAP to extracellular chromatin in vivo and supports the idea that SAP may have an important physiological role in the disposal of this material.

Cytokeratin 8 interacts with clumping factor B: a new possible virulence factor target.

Staphylococcus aureus is a human pathogen of growing clinical significance, owing to its increasing levels of resistance to most antibiotics. Infections range from mild wound infections to severe infections such as endocarditis, osteomyelitis and septic shock. Adherence of S. aureus to human host cells is an important step, leading to colonization and infection. Adherence is mediated by a multiplicity of proteins expressed on the bacterial surface, including clumping factor B. In this study, we aimed to identify new targets of clumping factor B in human keratinocytes by undertaking a genome-wide yeast two-hybrid screen of a human keratinocyte cDNA library. We show that clumping factor B is capable of binding cytokeratin 8 (CK8), a type II cytokeratin. Using a domain-mapping strategy we identified amino acids 437-464 as necessary for this interaction. Recombinantly expressed fragments of both proteins were used in pull-down experiments and confirmed the yeast two-hybrid studies. Analysis with S. aureus strain Newman deficient in clumping factor B showed the clumping factor B-dependence of the interaction with CK8. We postulate that the clumping factor B-CK8 interaction is a novel factor in S. aureus infections.

[Immunofluorescence mapping for diagnosis of congenital epidermolysis bullosa]. / Mapeo por inmunofluorescencia para el diagnóstico de epidermólisis ampollosa congénita.

The tools for diagnosis of epidermolysis bullosa have advanced greatly since Hintner's group introduced antigen mapping as a diagnostic test for this family of genodermatoses. Monoclonal or polyclonal antibodies raised against some of the specific proteins found in the epidermis and basement membrane of the epidermis have allowed 4 types of epidermolysis bullosa de be identified and all variants to be classified. When a newborn baby presents with blisters, many conditions are implicated in the differential diagnosis. Examination under an optical microscope can suggest epidermolysis bullosa, but immunofluorescence mapping and electron microscopy are required for confirmation of the diagnosis and further classification of congenital epidermolysis bullosa. This article explains the importance of immunofluorescence antigen mapping and describes the methods employed for classification and subclassification of epidermolysis bullosa.

In vitro complement binding on cytoplasmic structures in normal human skin: immunoelectronmicroscopic studies.

We have previously provided evidence that suggests that exposure of cryostat skin sections to normal human serum (NHS) results in the antibody-independent Clq binding to cytoplasmic structures of various cell types, leading to classical complement pathway activation as evidenced by cytoplasmic C3 deposition. In the present study, we have employed immunoelectronmicroscopic methods to clarify the exact nature of cytoplasmic C3 binding structures. Incubation of cryostat skin sections with NHS followed by peroxidase-labeled rabbit anti-human C3 serum (HRP-R/Hu C3) revealed that intracytoplasmic binding of C3 occurred in suprabasal keratinocytes, melanocytes, fibroblasts, smooth muscle cells, endothelial cells, pericytes, Schwann cells, and nerve axons, but not in basal keratinocytes, Langerhans cells, and other cellular constituents of the skin. C3 binding, as revealed by the deposition of HRP reaction product, was exclusively confined to intermediate-sized filaments (ISF), which can therefore be considered to represent the subcellular site for classical complement pathway activation. Under experimental conditions that do not allow classical complement pathway activation, ISF were not decorated. Our observation that ISF of ontogenetically different cell types share the capacity of complement fixation is in accordance with the recent finding that different ISF types, despite their biochemical and antigenic heterogeneity, have common alpha-helical domains and may provide a clue to the mechanism and site of interaction between complement components and ISF.

[Unilateral localized bullous pemphigoid following radiotherapy]. / Unilateral lokalisiertes bullöses Pemphigoid nach Radiotherapie.

A 74-year-old woman presented with a four-week history of locally expanding, highly pruritic urticarial plaques, bullae and erosions on her left breast. She had undergone surgery for an infiltrating ductal carcinoma of the same breast six months before and received intra- and postoperative radiotherapy (RT) followed by adjuvant hormonal anticancer treatment. Histopathological, immunological and serological data confirmed the diagnosis of localized bullous pemphigoid (BP) and treatment with systemic and local corticosteroids led to a sustained remission. After excluding other factors, we concluded that RT was the most likely trigger of her localized BP.

[Orogenital and conjunctival involvement in hereditary and autoimmune blistering diseases]. / Schleimhautbeteiligung bei blasenbildenden Erkrankungen.

Chronic involvement of orogenital and conjunctival mucosa in the course of either genetically based (epidermolysis bullosa hereditaria) or auto-immunologically mediated (as for example pemphigus vulgaris, mucous membrane pemphigoid or epidermolysis bullosa acquisita) blistering diseases can cause significant morbidity. To provide accurate care, recognition of clinical, pathogenic and diagnostic features as well as awareness of recent advances in the development of new therapeutic modalities are mandatory and thus will be discussed in this review.

[Hereditary blistering diseases. Symptoms, diagnosis and treatment of epidermolysis bullosa]. / Erbliche blasenbildende Erkrankungen. Klinik, Diagnostik und Therapie der Epidermolyis bullosa.

Hereditary epidermolysis bullosa (EB) is a term for a heterogeneous group of rare genetic disorders characterized by marked fragility of the skin and mucous membranes following minor trauma. Significant progress has been made in understanding the molecular basis of EB, which has far-reaching implications for an improved classification with consequences for prognosis, genetic counseling, DNA-based prenatal and preimplantation testing, and the development of future treatments including gene therapy. Besides mucocutaneous changes, EB leads to a number of systemic manifestations whose management requires multidisciplinary access. Extracutaneous complications include ophthalmologic, dental, gastrointestinal, pulmonary, urogenital, hematologic, and nutritional problems. This article reviews the progress that has been made in the understanding of the molecular basis of EB, clinical aspects of major EB subtypes, and the management of patients suffering from EB, and it gives an outlook on molecular therapy projects such as gene, cell, vector, and protein therapies.

Nonsense-associated altered splicing of the Patched gene fails to suppress carcinogenesis in Gorlin syndrome.

Mutations in the gene coding for the transmembrane receptor protein Patched (PTCH) are implicated in the autosomal dominant disorder Gorlin syndrome (also known as naevoid basal cell carcinoma syndrome), characterized by congenital abnormalities and cancer predisposition. Tumour promotion is thought to be associated with aberrant function of PTCH, leading to misregulation of the hedgehog signalling network. However, the transcriptional events that underlie the reduced tumour suppression effects of PTCH have not been studied in detail. We describe a patient with Gorlin syndrome who had three molecular aberrations resulting in biallelic disruption of the PTCH gene, leading to abnormal protein expression and development of basal cell carcinoma. Remarkably, within tumour cells, the somatic nonsense mutation G1019X was associated with activation of a cryptic splice donor site, in which an in-frame deletion of the exon sequence containing the nonsense mutation occurred. However, the function of the resulting PTCH protein variant was still compromised. The pathogenetic alterations described give insights into the sequence of events leading to cellular transformation and underscore the importance of the PTCH protein in skin homeostasis.

Human upper epidermal cytoplasmic antibodies are directed against keratin intermediate filament proteins.

Upper cytoplasmic (U-Cyt) antibodies are directed against cytoplasmic antigens found in keratinocytes in the upper layers of the epidermis. Until now, they have been defined by indirect immunofluorescence and are known to occur in the sera of patients with cutaneous diseases such as bullous dermatoses, basal cell carcinomas, and melanomas. An increased incidence of U-Cyt antibodies has also been reported in the sera of patients with noncutaneous diseases, such as pulmonary neoplasms. They have been found in addition in the sera of some normal individuals. In this study we have identified keratin intermediate filaments (KIF) as antigens U-Cyt antibodies are directed against. KIF proteins were prepared, separated by polyacrylamide gel electrophoresis, transblotted to nitro-cellulose strips, and used as substrates for antibody binding. Sera containing U-Cyt antibodies by indirect immunofluorescence also had antibodies that were directed against high molecular weight (65,000, 63,000, 61,500) KIF proteins. When KIF proteins were separated according to their charge and their molecular weight by two-dimensional gel electrophoresis and transblotted, the anti-KIF protein antibodies bound to virtually all charge isomers of the KIF proteins at the respective molecular weight. The antibody titers measured using the transblotting technique were 10 to 160 times higher than those found by indirect immunofluorescence. To determine whether U-Cyt antibodies were directed against KIF, a series of absorption and elution experiments were performed. Absorption of test sera with purified KIF removed both U-Cyt antibodies and anti-KIF protein antibodies. Absorption with another type of intermediate filament derived from fibroblasts, vimentin, did not remove U-Cyt or anti-KIF protein antibodies. Absorbed U-Cyt and anti-KIF protein antibodies were both eluted from the same KIF preparation and shown to bind to U-Cyt antigens by indirect immunofluorescence and KIF proteins by transblotting. Absorption of a serum containing U-Cyt antibodies, anti-nuclear antibodies, and anti-basement membrane zone antibodies with purified KIF resulted in the removal of the U-Cyt antibodies but not the other types of antibody. In addition, all test sera, even those that lacked U-Cyt antibodies, were found to have low-titer antibodies against KIF proteins by the transblotting technique. These data indicate that KIF proteins bear antigens to which U-Cyt antibodies are directed and that low titer antibodies against KIF proteins may be much more common than previously appreciated.

Revertant mosaicism: partial correction of a germ-line mutation in COL17A1 by a frame-restoring mutation.

Generalized atrophic benign epidermolysis bullosa is an autosomal recessive subepidermal blistering disease typified by null mutations in COL17A1. In 1 large kindred, affected individuals were homozygous for a 2-bp deletion in COL17A1, 4003delTC, which resulted in a downstream premature termination codon, nonsense-mediated mRNA decay, and abrogation of type XVII collagen synthesis. Interestingly, 1 of these patients, although phenotypically identical to her affected siblings, showed focal expression of type XVII collagen in epidermal basement membrane in a pattern suggestive of revertant mosaicism. When studies of randomly obtained epidermal, oromucosal, and peripheral blood cells failed to identify the genetic basis of this apparent mosaicism, microscopic subpopulations of potentially revertant epidermal cells (i.e., those overlying basement membrane containing type XVII collagen) were selectively isolated using laser capture microdissection. Analysis of DNA and RNA from these cells revealed a second mutation, 4080insGG, on 1 allele of COL17A1. This 2-bp insertion corrected the reading frame just proximal to the premature termination codon, countered nonsense-mediated mRNA decay, and allowed protein production by patient keratinocytes in vivo and in vitro. These studies elucidate the molecular basis of a novel form of revertant mosaicism in humans.

Relative quantitation of protein-protein interaction strength within the yeast two-hybrid system via fluorescence beta-galactosidase activity detection in a high-throughput and low-cost manner.

The yeast two-hybrid (Y2H) method is capable of delivering vast amounts of interacting positive yeast colonies from a single library screen, particularly if a multifunctional protein is used as bait. However, the selection of definitive colonies for further molecular analysis is limited by both technical practicality and high costs. Here we demonstrate a cost-effective and simple method for the rapid selection and ranking of those Y2H-positive interaction clones that are suitable for further analysis. We performed a Y2H screen for the identification of human transforming growth factor beta2- interacting proteins in a human skin keratinocyte library. The identified clones were ranked by the amount of beta-galactosidase enzyme produced, as well as by the interaction strength of the positive colonies. The combination of high-throughput microplate fluorescence readers and specific fluorescence assays can be utilized for relative quantitation of protein-protein interaction strength of Y2H-positive colonies in crude yeast-cell lysates. We demonstrate here that the high sensitivity of the fluorescence approach can bypass cumbersome conventional methods of cell lysis used in beta-galactosidase assays, and still deliver accurate values for analysis of protein interaction data. Finally, we also achieved a better understanding of general aspects of beta-galactosidase measurements in the Y2H system, such as protein normalization, the influence of yeast culture incubation time on optimal beta-galactosidase detection, and the linearity of beta-galactosidase detection in crude cell lysates.

Ocular involvement in anti-epiligrin cicatricial pemphigoid.

PURPOSE: To report an anti-epiligrin cicatricial pemphigoid (AECP) patient with severe ocular involvement and to provide a practical approach to distinguishing AECP patients from those with other subepidermal blistering diseases. METHODS: Techniques included direct and indirect immunofluorescence microscopy, Western blot and immunoprecipitation studies, as well as interdisciplinary examinations of mucous membranes and skin. RESULTS: This study describes a patient with clinical features of cicatricial pemphigoid, circulating anti-basement membrane zone IgG antibodies, and subepidermal blisters. Histopathology and immunofluorescence analysis suggested the diagnosis of a cicatricial pemphigoid-like type of epidermolysis bullosa acquisita. However, Western blot and immunoprecipitation studies demonstrated that the patient's serum contained autoantibodies against laminin 5 alpha3 subunit, leading to the diagnosis of an AECP. CONCLUSION: Since patients with AECP have an increased relative risk for malignant tumors, it is important to distinguish this entity within the spectrum of cicatricial pemphigoid patients by additional studies such as Western blot or immunoprecipitation.

Keratin intermediate filaments bear antigenic determinants for stratum corneum antibodies.

Stratum corneum (SC) antibodies are directed against antigens in the SC of the epidermis and are known to occur in all normal human sera. They have been shown by indirect immunofluorescence to be frequently associated with upper cytoplasmic (U-Cyt) antibodies. We have recently identified keratin intermediate filaments (KIF) as antigens for U-Cyt antibodies. In this study we investigated whether KIF also bear antigenic sites for SC antibodies. Normal human sera that contained SC and/or U-Cyt antibodies by indirect immunofluorescence were studied. Using immunoblot techniques 3 selected sera were shown to bind to high-molecular-weight (HMW) KIF proteins which had been extracted from 2 different epidermal cell preparations, that is, human callus or epidermis from which the SC had been removed by tape-stripping. The 3 test sera were absorbed on KIF which had been reconstituted in vitro from urea extracts from both epidermal substrates. As shown by indirect immunofluorescence, the SC and U-Cyt antibodies of all 3 sera were absorbed out with KIF from callus and with KIF from epidermis without SC. Immunoblot experiments, which are more sensitive than indirect immunofluorescence, demonstrated the absorption of anti-KIF protein antibodies of the 3 test sera on callus KIF and 2 of the sera on KIF obtained from epidermis without SC. This was shown by the lack of staining of the respective HMW KIF proteins with the postabsorption sera. With the third serum a marked reduction of antibody binding was found after absorption on KIF from epidermis without SC. These data indicate that KIF bear antigenic sites for SC antibodies.

Immunologic properties of enzymatically degraded human keratin intermediate filaments.

In order to gain insight into the metabolism of keratin intermediate filaments (KIF) as well as the ability of KIF degradation products to interact with the immune system, we performed enzymatic degradation of purified KIF and examined their interaction with anti-KIF autoantibodies and their ability to act as immunogens. Aliquots of KIF aggregates were exposed to 3 different enzymes, that is, alpha-chymotrypsin, plasmin, and trypsin, in dose- and time-dependent experiments. The effect of the digestion was monitored sequentially by polyacrylamide gel electrophoresis and simultaneously by transmission electron microscopy. Furthermore, the KIF degradation proteins were then examined for their ability to bind anti-KIF autoantibodies by immunoblot and for their immunogenicity. In addition, preincubation of KIF with anti-KIF autoantibodies prior to the digestion procedure was performed to investigate a possible protective effect of this treatment against proteolytic degradation. The experiments demonstrated that: (1) KIF are degraded by serine proteinases, (2) with prolonged incubation time intact KIF are progressively replaced by more granular-amorphous material in transmission electron microscopy, (3) anti-KIF autoantibodies bind to KIF degradation proteins, (4) preincubation of KIF with anti-KIF autoantibodies does not exert any major protective effect for KIF against proteolytic degradation, and (5) the enzymatic degradation products of KIF can function as effective immunogens causing the formation of high-titer anti-KIF antibodies.

Tissue amyloid P component in normal human dermis is non-covalently associated with elastic fiber microfibrils.

Tissue amyloid P component (TAP), a protein that crossreacts immunohistochemically with the normal plasma glycoprotein serum amyloid P component (SAP), is invariably associated with elastic fiber microfibrils in adult humans. We have investigated the nature of this association. Aliquots of minced, homogenized dermis, obtained following ethylenediamine tetraacetic acid (EDTA) separation of whole adult human skin, were extracted with different reagents, and the presence or absence of TAP in the pellet and in the supernatant following centrifugation was determined by SDS-PAGE and immunoblotting using anti-SAP antibodies. TAP was extractable from dermis using reagents which disrupt non-covalent bonds, including sodium dodecyl sulfate (SDS) and guanidine hydrochloride. TAP was not extracted by high molarity salt solutions, non-ionic detergents, or the reducing agents dithiothreitol and 2-mercaptoethanol. EDTA solution was similarly unsuccessful at eluting TAP from the dermal preparation, indicating that the association of TAP with elastic fiber microfibrils is not simply the result of Ca++-dependent binding. Collagenase solubilized some TAP, but this does not prove covalent linkage to elastic tissue of part of the TAP, because the apparent Mr of TAP extracted was identical to that of normal SAP subunits. We cannot completely exclude the possibility that a few subunits in each multimeric TAP molecule are covalently attached to the microfibrils. However, our findings that denaturing agents alone extracted most of the TAP from normal human dermis strongly suggest that the great majority of the dermal TAP is non-covalently bound to elastic fiber microfibrils. Thus TAP is not an integral constitutent of elastic fiber microfibrils.

Vitronectin shows complement-independent binding to isolated keratin filament aggregates.

Keratinocyte cell death, whether produced by skin disease or by physiologic apoptosis in normal skin, may result in formation of dermal keratin bodies, consisting mainly of keratin intermediate filament aggregates. Vitronectin, a multifunctional plasma and tissue glycoprotein, which inhibits the complement membrane attack complex and promotes cell attachment and spreading, is, like amyloid P component, associated with keratin bodies in vivo. To investigate a potential role for vitronectin in the removal of keratin bodies, we studied the interaction of vitronectin with keratin intermediate filaments in normal human skin and in Hep-2 cells, as well as with isolated keratin intermediate filament aggregates in vitro. Following pre-incubation of skin sections and Hep-2 cells with normal human serum (as a source of vitronectin), cytoplasmic staining of keratinocytes and of cytoskeletal filaments in Hep-2 cells was observed by immuno-fluorescence staining with polyclonal and monoclonal anti-vitronectin antibodies. Vitronectin binding to keratin intermediate filament aggregates extracted from normal human epidermis was demonstrated by immunofluorescence and by immunoblotting, and was not dependent on complement activation, because it occurred even when heat-inactivated human serum or C4-deficient serum was used as a source of vitronectin. Amyloid P component shows Ca++- dependent binding to keratin intermediate filament aggregates. does not involve amyloid P component because it occurred when binding of the latter protein was inhibited by EDTA buffer. Moreover, purified vitronectin also bound to keratin intermediate filament aggregates in immunofluorescence studies. Vitronectin binding to keratin intermediate filaments may play a role both in limiting complement-mediated tissue damage (because keratin bodies may activate complement) and in promoting removal of keratin bodies by fibroblasts and/or macrophages.

The effect of retinoic acid on the expression of pemphigus and pemphigoid antigens in cultured human keratinocytes.

Vitamin A and its derivatives (retinoids) have both profound effects on epidermal differentiation and beneficial therapeutic effects in various dermatologic diseases. In order to understand these effects, much work has been done with cultured keratinocytes, which show specific morphologic, cellular, and biochemical changes modulated by retinoids. In an attempt to further define specific molecular effects of retinoids in cultured human keratinocytes, we studied the expression of pemphigus (P) and pemphigoid (BP) antigens by human keratinocytes cultured with retinoic acid (RA) in concentrations which modulated differentiation. Cultures of human keratinocytes in medium with 10% delipidized fetal bovine serum (vitamin A-depleted medium) demonstrated areas of extensive differentiation with flattened stratifying cells, keratohyaline granules, and an anucleate stratum corneum-like superficial layer. These cells also synthesized a 67 kd keratin, characteristic of well-differentiated epidermis. In contrast, cultures of human keratinocytes in the same medium supplemented with (10(-7) M, 3 X 10(-7) M, or 10(-6) M) RA demonstrated less differentiated small cuboidal cells that were stratified but did not form an anucleate layer or keratohyaline granules, and did not synthesize the 67 kd keratin. In order to detect P and BP antigens in these cultures, we used indirect immunofluorescence. In vitamin A-depleted cultures, P antigen either was not detected or was seen focally on the cell surface of basal cells. BP antigen was seen on the basal pole of the basal cells, approximating its in vivo location. In RA-treated cells, P antigen was seen on the cell surface of most of the cells, and BP antigen was seen throughout the cytoplasm of the basal cells. In order to study the expression of newly synthesized antigens, we radiolabeled cultures with 14C-amino acids and quantitatively immunoprecipitated the antigens, which were then identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis. We detected a major decrease in newly synthesized P antigen precipitated from extracts of vitamin A-depleted cells compared to RA-supplemented cells, whereas amounts of newly synthesized BP antigen were about the same. Taken together these data demonstrate that RA, at concentrations that decrease differentiation of cultured human keratinocytes, increases the expression of P antigen and changes the subcellular location of BP antigen.