Search PubMed⌕ Search

Biomedical subjects

D Jullien

Publications and source records attributed to D Jullien.

At least 19 recordsLinked to original sources
PubMed2005

TGFbeta inhibits CD1d expression on dendritic cells.

The CD1 family of cell surface glycoprotein has been demonstrated to be a third lineage of antigen-presenting molecules for specific T cell responses. They present lipidic, glycolipidic antigen and hydrophobic peptide to T cells. CD1d restricted T cells play a role in autoimmune disease and in tumor immunity. Transforming growth factor beta (TGFbeta), a member of the family of polypeptide growth factors synthetized by human keratinocytes, has inhibitory effects on proliferation and differentiation of immune cells, especially on CD1d-restricted natural killer T cells. These properties led us to investigate the role of TGFbeta in CD1d expression on dendritic cells (DC), which are known to play a key role in initiation of the immune response. Here, we observed CD1d molecules on DC developed from PBMC with GM-CSF and IL4 but not with GM-CSF, IL4 and TGFbeta for 7 d. RT-PCR and FACS analysis (mAb 42.1) performed at various stages of differentiation on CD34+ HPC show that CD1d mRNA levels and CD1d molecule expression at the cell surface decreased progressively during the differentiation process. Thus, while committing DC-precursors differentiation toward the Langerhans cell (LC) pathway, TGFbeta likely inhibits CD1d transcription. Therefore, LC freshly recovered from epidermal sheet were evaluated by flow cytometry. In accordance with in vitro observation, they did not expressed measurable levels of CD1d molecules at the cell membrane. Thus, TGFbeta produced by keratinocytes contribute to selectively downregulate CD1d expression on intraepidermal-resident LC.

Antigens, CD1↗
PubMed2004

T-cell modulation for the treatment of chronic plaque psoriasis with efalizumab (Raptiva): mechanisms of action.

Psoriasis is a chronic, incurable, auto-immune disorder with cutaneous manifestations. New evidence on the central role of the immune system in the pathogenesis of psoriasis increasingly provides insight into pathogenic steps that can be modulated to provide disease control. Numerous biological therapies are in various stages of clinical development, with expectation of providing enhanced safety and efficacy over currently available psoriasis therapies. Efalizumab, a recombinant humanized monoclonal IgG1 antibody, is a novel targeted T-cell modulator that inhibits multiple steps in the immune cascade that result in the production and maintenance of psoriatic plaques, including initial T-cell activation and T-cell trafficking into sites of inflammation, including psoriatic skin, with subsequent reactivation in these sites. This article reviews the pharmacodynamic, pharmacokinetic and clinical effects observed during phase I, II and III efalizumab trials in patients with moderate to severe chronic plaque psoriasis.

Adjuvants, Immunologic↗
PubMed2003

[Acquired zinc deficiency in a breast-fed premature infant].

UNLABELLED: Symptomatic zinc deficiency can occur in exclusively breast-fed infants. We report a case in a preterm infant. CASE REPORT: A 3-months-old exclusively breast-fed premature infant presented with peri-orificial and acral eczematoid lesions. Laboratory investigations revealed lowered zinc levels in the infant's serum and in her mother's milk. A rapid healing occurred after oral zinc supplementation. DISCUSSION: Zinc deficiency in breast-fed infants is a rare disease caused by a low level of zinc in mother's milk. The clinical features resemble those of acrodermatitis enteropathica. Oral zinc supplementation is required until weaning.

Breast Feeding↗
PubMed2003

Angioedema and oral contraception.

BACKGROUND: Oral contraceptives can precipitate attacks of hereditary angioedema (ANE) or induce acquired forms. OBJECTIVE: We studied 5 patients who had an ANE which had begun under oral contraception and disappeared after stopping the pill. METHODS: We explored the clinical and biological characteristics of these patients. RESULTS: The symptoms developed during the first year or later after starting contraception; the patients reported relapsing swelling of the lips, hands, larynx and abdomen. All women had normal serum C4 and C1 inhibitor (C1Inh) antigen levels, but a lowered C1Inh activity, with a marked protein cleavage on the immunoblot. The suppression of the pill was associated with the regression of the edema and normalization of C1Inh function. CONCLUSION: The mechanism of these ANE is unknown. The could be due to a modulation of C1Inh expression upon androgens or an imbalance between coagulation proteins favoring C1Inh cleavage by its target proteases.

Adult↗
PubMed2000

Regeneration of cutaneous innervation in a human hand allograft.

On Sept 23, 1998, a human hand allograft was done in our hospital. We followed up the patients for 24 months to assess the skin structure by immunohistology. Most cutaneous structures (including dermal nerves with their Schwann cells and perineurial fibroblasts) were present immediately after surgery and remained detectable throughout the study; from day 464 onwards, axons became detectable within dermal nerves, and their density increased progressively with time. Merkel cells reappeared in the epidermis 12 months after the operation. The regeneration of cutaneous innervation paralleled the recovery of cutaneous sensitivity.

Antigens, CD34↗
PubMed2000

Overexpression of CD1d by keratinocytes in psoriasis and CD1d-dependent IFN-gamma production by NK-T cells.

The MHC class I-like protein CD1d is a nonpolymorphic molecule that plays a central role in development and activation of a subset of T cells that coexpress receptors used by NK cells (NK-T cells). Recently, T cells bearing NK receptors were identified in acute and chronic lesions of psoriasis. To determine whether NK-T cells could interact with epidermal cells, we examined the pattern of expression of CD1d in normal skin, psoriasis, and related skin disorders, using a panel of CD1d-specific mAbs. CD1d was expressed by keratinocytes in normal skin, although expression was at a relatively low level and was generally confined to upper level keratinocytes immediately beneath the lipid-rich stratum corneum. In contrast, there was overexpression of CD1d in chronic, active psoriatic plaques. CD1d could be rapidly induced on keratinocytes in normal skin by physical trauma that disrupted barrier function or by application of a potent contact-sensitizing agent. Keratinocytes displayed enhanced CD1d following exposure to IFN-gamma. Combining CD1d-positive keratinocytes with human NK-T cell clones resulted in clustering of NK-T cells, and while no significant proliferation ensued, NK-T cells became activated to produce large amounts of IFN-gamma. We conclude that CD1d can be expressed in a functionally active form by keratinocytes and is up-regulated in psoriasis and other inflammatory dermatoses. The ability of IFN-gamma to enhance keratinocyte CD1d expression and the subsequent ability of CD1d-positive keratinocytes to activate NK-T cells to produce IFN-gamma, could provide a mechanism that contributes to the pathogenesis of psoriasis and other skin disorders.

Adult↗
PubMed2000

Induction of early transcription in one-cell mouse embryos by microinjection of the nonhistone chromosomal protein HMG-I.

In the mouse embryo, the onset of zygotic transcription occurs at the end of the first cell cycle, upon completion of DNA replication. We show that the nonhistone chromosomal protein HMG-I, whose translocation into the pronuclei of one-cell embryos is linked to this first round of DNA synthesis, plays a critical role in the activation of zygotic transcription. Indeed, microinjection of purified HMG-I results in a higher nuclear accumulation of the protein and triggers an earlier activation of zygotic transcription, an effect which is abolished by the preincubation of the protein with a specific antibody directed against its AT-hook DNA-binding motifs. Significantly, microinjection of this antibody also prevents the normal onset of transcription in the embryo, suggesting that endogenous HMG-I is similarly involved in this process. Finally, microinjection of the exogenous protein modifies chromatin structure as measured by in situ accessibility to DNase I. We propose that general chromosomal architectural factors such as HMG-I can modulate the accessibility of chromatin to specialized regulatory factors, thereby promoting a transcriptionally competent state.

Animals↗
PubMed2000

Evidence for human CD4+ T cells in the CD1-restricted repertoire: derivation of mycobacteria-reactive T cells from leprosy lesions.

Both the CD4-CD8- (double negative) and CD4-CD8+ T cell lineages have been shown to contain T cells which recognize microbial lipid and glycolipid Ags in the context of human CD1 molecules. To determine whether T cells expressing the CD4 coreceptor could recognize Ag in the context of CD1, we derived CD4+ T cell lines from the lesions of leprosy patients. We identified three CD4+ Mycobacterium leprae-reactive, CD1-restricted T cell lines: two CD1b restricted and one CD1c restricted. These T cell lines recognize mycobacterial Ags, one of which has not been previously described for CD1-restricted T cells. The response of CD4+ CD1-restricted T cells, unlike MHC class II-restricted T cells, was not inhibited by anti-CD4 mAb, suggesting that the CD4 coreceptor does not impact positive or negative selection of CD1-restricted T cells. The CD4+ CD1-restricted T cell lines produced IFN-gamma and GM-CSF, the Th1 pattern of cytokines required for cell-mediated immunity against intracellular pathogens, but no detectable IL-4. The existence of CD4+ CD1-restricted T cells that produce a Th1 cytokine pattern suggests a contributory role in immunity to mycobacterial infection.

Antigen Presentation↗
PubMed2000

Sequential histological and immunohistochemical study of the skin of the first human hand allograft.

BACKGROUND: On September 1998, the first human hand allograft was successfully performed in Lyon. METHODS: A 48-year-old white man who had suffered accidental amputation of the arm in 1984, received a forearm and hand allograft from a 42-year-old white male cadaveric heart-beating donor. Immunosuppressive therapy included prednisone, mycophenolate mofetil, FK506, and antithymocyte globulins. Sequential skin biopsies were taken from the grafted limb and examined (immuno)histologically to detect a possible graft rejection and to evaluate the structural integrity of the skin of the allograft. RESULTS: The skin showed histologically a normal appearance, except on days 57 and 63, when a mononuclear perivascular cell infiltrate was observed in the dermis; this appeared concomitantly with erythematous lesions of the skin that developed after a slight decrease of the immunosuppressive treatment. These changes were considered as signs of graft rejection, and were reversed by an increase of the immunosuppressive treatment. No skin necrosis was seen at any time. Immunohistochemically, the main cell types of the skin were present throughout the study. From day 77 onward the epidermis of the grafted hand harbored some epidermal Langerhans cells of recipient's origin. CONCLUSION: This study shows that the skin of the hand allograft maintains overall a normal histological structure and contains most essential cell types, including cells of recipient origin, such as Langerhans cells. Furthermore, it shows that in this system of composite tissue transplantation, skin biopsies may reveal a starting graft rejection, before the appearance of clinically obvious lesions.

Adult↗
PubMed2000

[Perianal streptococcal dermatitis].

BACKGROUND: Pediatric perianal streptococcal dermatitis (PSD) is a well-defined clinical entity. However, its highly uniform presentation remains surprisingly unrecognized by many practitioners 33 years after its first description. CASE REPORT: A seven-year-old girl had a three-week history of perianal and vulva redness with well-defined margins. Functional symptoms associated perirectal tenderness and pain during defecation, which was responsible for constipation. At onset she also presented with a sore throat, which resolved spontaneously, and she had been complaining for a few days about a perioral impetigo. She received mycostatin unsuccessfully for an alleged candidiasis. Positive cultures for group A beta-hemolytic streptococci from both perirectal and perioral swabs confirmed the diagnosis of PSD. Therapy with amoxicillin (50 mg/kg/d) was prescribed for ten days. Perianal lesions were cleared by day 2. CONCLUSION: Since PSD can masquerade as candidiasis, psoriasis, seborrheic dermatitis, inflammatory bowel disease or even sexual abuse, it remains an underdiagnosed entity. This situation leads to delayed diagnosis and treatment which in turn might increase the frequency of secondary complications related to streptococcal infections (i.e., post-streptococcal acute nephritis and rheumatism, guttate psoriasis, etc.).

Amoxicillin↗