Childhood epidermal necrolysis and erythema multiforme major: a multicentre French cohort study of 62 patients.

INTRODUCTION: The distinction between epidermal necrolysis [EN; including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN) and overlap syndrome] and erythema multiforme major (EMM) in children is confusing. We aimed to better describe and compare these entities. MATERIALS AND METHODS: This French retrospective multicentre study included children ≤18 years old referred for EN or EMM between 1 January 2008 and 1 March 2019. According to pictures, children were reclassified into TEN/overlap, SJS or EMM/unclassified (SJS/EMM) groups and compared for epidemiological and clinical data, triggers, histology and follow-up. RESULTS: We included 62 children [43 boys, median age 10 years (range 3-18)]: 16 with TEN/overlap, 11 SJS and 35 EMM. The main aetiologies were drugs in EN and infections (especially Mycoplasma pneumoniae) in EMM (P < 0.001), but 35% of cases remained idiopathic (TEN/overlap, 47%; SJS, 24%; EMM, 34%). The typical target lesions predominated in EMM (P < 0.001), the trunk was more often affected in EN (P < 0.001), and the body surface area involved was more extensive in EN (P < 0.001). Mucosal involvement did not differ between the groups. Two patients with idiopathic TEN died. Histology of EMM and EN showed similar features. The recurrence rate was 42% with EMM, 7% with TEN/overlap and 0 with SJS (P < 0.001). Sequelae occurred in 75% of EN but involved 55% of EMM. CONCLUSION: Clinical features of EN and EMM appeared well demarcated, with few overlapping cases. Idiopathic forms were frequent, especially for EN, meaning that a wide and thorough infectious screening, repeated if needed, is indicated for all paediatric cases of EN/EMM without any trigger drug. We propose a comprehensive panel of investigations which could be a standard work-up in such situation. Sequelae affected both EN and EMM.

[Leg ulcers occurring under tyrosine kinase inhibitor therapy (sunitinib, nilotinib)]. / Ulcères des membres inférieurs développés sous inhibiteurs de tyrosine kinase (sunitinib, nilotinib).

BACKGROUND: Certain anticancer drugs are known to induce leg ulcers, mainly chemotherapy agents such as hydroxyurea. We report 2 cases of leg ulcers in cancer patients treated with the tyrosine kinase inhibitors, sunitinib and nilotinib, and we discuss the role of these treatments in the pathogenesis of leg ulcers. PATIENTS AND METHODS: Case 1. A 62-year-old patient on sunitinib for intrahepatic cholangiocarcinoma developed a lesion on her right foot. The vascular evaluation was negative. After progressive worsening, sunitinib was stopped and healing was observed within a few months. Case 2. A 83-year-old patient had been treated for chronic myeloid leukemia since 2005. Nilotinib was introduced in 2009. Peripheral arterial revascularization was required in May 2013. A few months later, worsening was noted with the onset of ulceration and necrosis of the third toe. Further revascularisation surgery was performed, and nilotinib was suspended and antiplatelets introduced. Healing occurred a few months later. DISCUSSION: Many skin reactions have been described in patients on nilotinib and sunitinib, but few publications report the development of de novo ulcers in patients without risk factors. The pathophysiology of the development of ulcers in patients receiving tyrosine kinase inhibitors is not clear, and probably involves several mechanisms of action. The increasing use of this type of treatment could lead to an upsurge in the incidence of vascular complications. CONCLUSION: We report two cases of leg ulcers developing in patients on tyrosine kinase inhibitors and raise the question of causal implication of these treatments in the pathogenesis of ulcers.

[Wound dressing. Nursing knowledge and practice]. / Nettoyage des plaies. Connaissances et pratiques des infirmiers.

BACKGROUND: Wound management constitutes an important public health issue. Health authorities have published numerous recommendations on wound cleansing and dressing. The French law currently authorizes nurses to prescribe wound care with a doctor's agreement. Further, they have an essential role in wound management. In this study, we evaluate nurses' behavior in wound cleansing in outpatients and in hospital settings. PATIENTS AND METHODS: The survey was conducted from 4/1/11 to 5/6/11 in 111 nurses working at Argenteuil Hospital and in 299 nurses with outpatient activity within two administrative departments (Hauts-de-Seines and Val-d'Oise) in the suburbs of Paris, France. The questionnaire included items relating to the use of antiseptics during cleansing of various types of wounds, with or without signs of super-infection, and with or without medical prescription. The results were compared with French references. RESULTS: One hundred and ninety-one answers were obtained: 111 (100%) from the hospital and 80 (27%) from nurses with outpatient activity (women: 88%, mean age=36 years). The mean number of wounds seen per week was 18 (0-135). In the absence of a prescription, antiseptics were used by less than 35% of the nurses for chronic wounds and burns but by more than 50% for operative and traumatic wounds. When water or physiological serum was prescribed for wound cleansing, these figures were slightly lower. Conversely, if an antiseptic was prescribed, more than 50% of the nurses used antiseptics. Where nurses disagreed with the medical prescription, more than 60% of the hospital nurses discussed this with the doctor, compared to less than 40% of private nurses. In the event of signs of super-infection, more than 85% of the nurses used antiseptics, with or without medical prescription, and in the case of disagreement, more than 90% called the doctor, whether working in a hospital setting or among outpatients. The alternative to an antiseptic was physiological saline for 60 to 80% of the nurses, with sterile water or tap water being used by less than 45%. DISCUSSION: Antiseptics continue to be used in situations in which they are no longer recommended (e.g. chronic wounds, operative wounds, super-infected wounds) whereas they are used very little for burns, where they are in fact recommended during the acute phase. This is true both with and without medical prescription. Prescriptions are not always followed in practice and prescriptions of antiseptics are more often respected than prescriptions of water or physiological saline solution. Discussion with the prescribing doctor is more frequent among hospital nurses than among private nurses.

Nomenclature of prominin-1 (CD133) splice variants - an update.

Prominin-1 (CD133), a pentaspan membrane glycoprotein that constitutes an important cell surface marker of various, either normal or cancerous, stem cell populations is widely used to isolate or characterize such cells in different systems. Occurring throughout the metazoan evolution with a remarkably conserved genomic organization, it may be expressed as different splice variants with distinctive characteristics. A rational nomenclature has been proposed earlier for their consistent designation across species. Although generally accepted, it seems to be misunderstood in view of the recent report of novel prominin-1 complementary DNAs in rhesus monkey and humans with improper naming. As this may lead to confusion, we have reexamined the genomic organization of prominin-1 in various primates to provide an update that should further clarify the rationale of the nomenclature for prominin-1 gene products. This report comprises (i) the determination of the genomic organization of prominin-1 gene in two non-human primates, i.e. Macaca mulatta and Pan troglodytes, commonly used in research, (ii) the mapping of a new exon that creates an alternative cytoplasmic C-terminal end of prominin-1, (iii) the identification of various potential PDZ-binding domains generated by alternative cytoplasmic C-terminal tails, suggesting that different prominin-1 splice variants might interact with distinct protein partners, and (iv) a summing up of the different prominin-1 splice variants.

Rat prominin, like its mouse and human orthologues, is a pentaspan membrane glycoprotein.

Mouse prominin is the first characterized member of a novel family of membrane glycoproteins. It displays a characteristic membrane topology with five transmembrane segments and two large glycosylated extracellular loops. Prominin orthologues and paralogues have been identified in human, fish, fly, and worm. Recently, a cDNA sequence encoding the rat homologue of mouse prominin has been reported [Zhu et al. (2001) Biochem. Biophys. Res. Commun. 281, 951-956]. Surprisingly, due to a single nucleotide deletion that shifts the reading frame and introduces a premature stop codon, the protein predicted from this cDNA would correspond to a C-terminally truncated form of prominin with only four transmembrane segments. Here we report evidence that is in contrast to the report of Zhu et al. (2001). We isolated a rat prominin cDNA devoid of any frameshift mutation, demonstrate that rat prominin, like the other mammalian prominins, is a full-length 120-kDa pentaspan membrane glycoprotein, and have not been able to detect any C-terminally truncated form of rat prominin.

Conformational alterations during biosynthesis of HLA-DR3 molecules controlled by invariant chain and HLA-DM.

HLA-DM is known to catalyze the exchange of class II-associated invariant chain (Ii) peptide (CLIP) for cognate peptide during biosynthesis. In DM-negative cells HLA-DR3 molecules have been shown to predominantly present CLIP and to lack the DR3-specific mAb epitope 16.23, which has led to the assumption that CLIP prevents binding of mAb 16.23. In the present study we show that CLIP does not prohibit 16.23 epitope expression, but that the formation of this epitope is directly influenced by interactions of the DR molecule with Ii and DM. Detergent solubilized DR3 from wild-type as well as DM(-) cells bound CLIP in a 16.23(+) mode. On cells, however, neither CLIP nor antigenic peptide bound to DR3 in a 16.23(+) conformation, unless HLA-DM was expressed. Thus, HLA-DM appears to alter the conformation of DR3 in a peptide-independent fashion. Since in DM-deficient cells that also lack Ii, DR3 molecules assembled in a 16.23(+) conformation, we conclude that during biosynthesis Ii and DM exert opposing conformational constraints, characterized by suppressing or releasing 16.23 epitope expression. These results imply that DR3/peptide complexes, including DR3/ CLIP, can exist in two conformations depending on previous interaction with DM, but independent of the nature of the peptide bound. We show that these naturally occurring class II conformers can be selectively recognized by T cells.

Prominin: a story of cholesterol, plasma membrane protrusions and human pathology.

Prominin is the first identified member of a novel family of polytopic membrane proteins conserved throughout the animal kingdom. It has an unusual membrane topology, containing five transmembrane domains and two large glycosylated extracellular loops. In mammals, prominin is expressed in various embryonic and adult epithelial cells, as well as in nonepithelial cells, such as hematopoietic stem cells. At the subcellular level, prominin is selectively localized in microvilli and other plasma membrane protrusions, irrespective of cell type. At the molecular level, prominin specifically interacts with membrane cholesterol and is a marker of a novel type of cholesterol-based lipid 'raft'. A frameshift mutation in the human prominin gene, which results in a truncated protein that is no longer transported to the cell surface, is associated with retinal degeneration. Given that prominin is concentrated in the plasma membrane evaginations at the base of the outer segment of rod photoreceptor cells, which are essential precursor structures in the biogenesis of photoreceptive disks, it is proposed that prominin has a role in the generation of plasma membrane protrusions, their lipid composition and organization and their membrane-to-membrane interactions.

The direct agglutination test: a non-specific test specific for the diagnosis of visceral leishmaniasis?

Serology has an important role to play in the diagnosis of the severe clinical syndrome of visceral leishmaniasis (VL). The direct agglutination test (DAT), a simple agglutination test which requires no laboratory facilities, has become the preferred test, particularly for field studies. The nature of the antigens responsible for the agglutination of leishmanial promastigotes by the serum of VL patients is not known. A series of experiments which provide some clues to the molecular basis for the test and which indicate that there might be more in DAT than meets the eye is reported.

An activated epidermal growth factor receptor/Lck chimera restores early T cell receptor-mediated calcium response in a CD45-deficient T cell line.

In T cells, cell surface expression of CD45, a transmembrane tyrosine phosphatase, is required for T cell receptor (TCR) signal transduction. Indirect evidence suggests that CD45 function in TCR signaling involves the dephosphorylation of the C-terminal negative regulatory site of p56(lck), Tyr-505. To evaluate the importance of CD45-mediated dephosphorylation of p56(lck) Tyr-505 in TCR signaling, we established CD45(-) Jurkat cell lines expressing various forms of a chimera containing the extracellular and transmembrane domains of the epidermal growth factor receptor (EGFR) fused to p56(lck). We report that an activated EGFR/Lck chimera is able to reconstitute a Ca2+ response after CD3 stimulation in the absence of CD45 expression. In addition, the wild-type and kinase inactive versions of the EGFR/Lck chimera fail to restore early signaling. Restoration of the response by EGFR/LckF505 required EGF binding to the chimeric kinase. Altogether, these results provide the first direct evidence that the lack of efficient dephosphorylation of p56(lck) Tyr-505 is, in part, responsible for the unresponsiveness of CD45(-) cells. They also indicate that a second event is required for p56(lck) function in TCR signaling in addition to its dephosphorylation at Tyr-505.

Synthetic peptide-based enzyme-linked immunosorbent assay for serodiagnosis of visceral leishmaniasis.

Synthetic peptides, derived from the amino acid sequence of a Leishmania donovani clone, were used to develop an enzyme-linked immunosorbent assay (ELISA) for detecting antibodies against L. donovani. For this purpose, five peptides were conjugated to a protein carrier, human serum albumin (HSA), by using a heterobifunctional reagent, epsilon-maleimidocaproic acid N-hydroxysuccinimide ester, to obtain a well-defined product. The sensitivity and the specificity of the peptide-specific ELISA were determined with a panel of 106 serum samples from individuals living in areas where visceral leishmaniasis is endemic; sera from post-kala azar dermal leishmaniasis-infected patients and from individuals suffering from other infectious diseases were also included. ELISAs were performed with either a single peptide-HSA conjugate or a mixture of two peptide-HSA conjugates. Ninety-seven percent of the serum samples from patients with visceral leishmaniasis had detectable antibodies to one or more of the single synthetic peptides. ELISA with a single peptide-HSA conjugate proved to be less sensitive (less than 71%) but more specific (up to 93%) than ELISA with crude promastigote antigens (80% sensitivity and 79% specificity); when a combination of two different peptide-HSA conjugates was used, the test increased both in sensitivity and in specificity. Chemically defined peptide-protein conjugates improve the reproducibility and reliability of ELISA for the serodiagnosis of L. donovani infection.

Identification of residues in the V domain of CD80 (B7-1) implicated in functional interactions with CD28 and CTLA4.

The CD80 (B7-1) molecule is a 45-60-kD member of the immunoglobulin superfamily that is expressed on a variety of cell types of haematopoietic origin. CD80 can provide a critical costimulatory signal to T cells by interacting with the T cell surface molecule CD28. CD80 also binds to the CD28-related molecule CTLA4, which is expressed on activated T cells, Recently, additional ligands of CD28 and CTLA4 have been described in mice and humans. One of them, CD86 (B-70 or B7-2) was characterized at the molecular level. Although similar in predicted structure to CD80, it is distantly related in amino acid sequence. In this study, human CD80 mutants were generated and tested for their ability to maintain the interaction with CD28 leading to adhesion and enhanced IL-2 production. Two hydrophobic residues in the V-like domain of CD80 were identified as critical for binding to CD28 and are also important for the interaction with CTLA4. These residues are adjacent to the epitope of the BB1 antibody, which inhibits CD28-CD80 interactions. One of these residues, Y87, is conserved in all CD80 and CD86 cloned from various species. These results being to unravel the structural requirements for binding to CD28 and CTLA4.

Differential effect of transforming growth factor beta on the synthesis of Th1- and Th2-like lymphokines by human T lymphocytes.

(TGF)-beta is a pluripotent cytokine exerting differential effects on distinct components of the immune response. The present report, based on lymphokine determination in culture supernatants and Northern blot analysis of lymphokine mRNA, demonstrates that TGF-beta 2 markedly inhibits interleukin (IL)-4 and IL-5 synthesis by polyclonally activated human T cells in the absence of any significant effect on (IFN)-gamma, lymphotoxin or IL-2, suggesting a modulatory effect of TGF-beta 2 on the interferon Th1/Th2) balance of immune responses. The inhibitory effect of TGF-beta on IFN-gamma production by unfractionated peripheral blood mononuclear cells is likely to reflect the blunting of natural killer cell activation by TGF-beta.

Recombinant interleukin-12 suppresses the synthesis of immunoglobulin E by interleukin-4 stimulated human lymphocytes.

Interleukin-12 is a recently discovered lymphokine displaying an array of in vitro activities suggesting a major role in protective immunity against infectious agents like viruses. This study provides evidence that IL-12 may also be implicated in the selection of the immunoglobulin isotypes. We show that picomolar concentrations of rIL-12 markedly inhibit the synthesis of IgE by IL-4-stimulated PBMC. The suppression of IgE is observed at the protein and at the mRNA levels, it is isotype specific, and it is abolished by neutralizing anti-IL-12 mAbs. IL-12 may suppress IgE synthesis by: (a) inducing the production of IFN-gamma, a known inhibitor of IgE synthesis and (b) by a novel mechanism which is IFN-gamma independent. The best evidence for this is from studies on IgE synthesis by IL-4-plus hydrocortisone-stimulated umbilical cord blood lymphocytes, which do not produce detectable amounts of IFN-gamma. In such cultures, rIL-12 inhibits IgE synthesis even in the presence of a large excess of neutralizing anti-IFN-gamma mAb.

Glucocorticoids suppress the production of interleukin 4 by human lymphocytes.

Given that glucocorticoids (GCS) were reported to increase the production of interleukin 4 (IL4) by mouse T cells and that GCS are widely used to treat allergic diseases it was important to examine the effect of these agents on IL4 production by human lymphocytes. We here demonstrate that the production of IL4 by human lymphocytes is markedly inhibited by small concentrations of hydrocortisone. The suppression is observed at the protein and at the mRNA levels and it is not secondary to the GCS-induced inhibition of IL2 production.

1,25(OH)2 vitamin D3 inhibits the CD23 gene expression by human peripheral blood monocytes.

A biologically active form of vitamin D, 1,25(OH)2D3, and a leukocyte surface molecule, CD23, play important roles in immune regulation. The effect of 1,25(OH)2D3 on the CD23 gene expression was examined in this study. The results show that 1,25(OH)2D3 suppresses spontaneous and IL-4-stimulated CD23 synthesis by peripheral blood monocytes. The inhibition occurs at both the protein and mRNA levels. However, 1,25(OH)2D3 has no inhibitory effect on CD23 production by either resting or activated tonsillar B cells. Our results suggest a possible role of 1,25(OH)2D3 in the regulation of certain immune and inflammatory responses via its effect on CD23 production.

Purification and partial characterization of rat macrophage Fc receptor and binding factor for IgA.

By using a biotinylated ligand and Western blotting techniques, a receptor (RFc alpha) and a binding factor (BF) for IgA were detected, respectively, on membrane and in the cell-free culture supernatant of rat peritoneal macrophages. Extraction of the RFc alpha was obtained by solubilization of macrophages with Nonidet P-40, and purification was performed by HPLC affinity chromatography on a column derivatized with IgA. RFc alpha is formed of two subunits, with molecular masses of 56 and 70 kDa, which are both involved in the IgA binding ability of rat peritoneal macrophages. IgABF was recovered from the cell-free supernatant of a short-term culture of rat macrophages and was affinity-purified in the same manner as RFc alpha. Like RFc alpha, IgABF retained its IgA binding activity in its native, as well as denatured form. Since the molecular masses of RFc alpha and IgABF are similar, and IgABF competes with RFc alpha for IgA binding, one can assume that IgABF probably represents a shed RFc alpha.

Recombinant interleukin 4 suppresses the production of interferon gamma by human mononuclear cells.

rIL-4 inhibits the production of IFN-gamma by PBMC stimulated with mitogens or allogeneic cells. The suppression is observed at the protein and at the mRNA level; it is dose and time dependent, and it is abolished by a neutralizing mAb to IL-4. It is suggested that the balance between the production of IL-4 and IFN-gamma may be significantly influenced by the chronological order of activation of their respective gene.