Michael D Rosenblum

Medical College of Wisconsin, Milwaukee, WI, United States

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Publications (9)45.92 Total impact

  • Michael D Rosenblum, Kim B Yancey, Edit B Olasz, Robert L Truitt
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    ABSTRACT: The "danger model" of immune recognition proposes that the immune system does not differentiate between self and non-self when deciding whether to mount a response, but instead, discerns between that which is dangerous or not dangerous to the host. Danger signals incite inflammatory responses, which can lead to the induction of tissue-specific autoimmunity. Immunosuppressive molecules expressed on selected cells have the potential to regulate tissue-specific inflammation, and consequently, autoimmunity. Recent studies have revealed that CD200, a potent immunoregulatory protein, is expressed on Langerhans cells (LCs) and keratinocytes (KCs) in mouse epidermis. CD200 expression is concentrated on KCs comprising the outer root sheath (ORS) of murine hair follicles (HF). Skin deficient in CD200 is highly susceptible to HF-associated inflammation and immune-mediated alopecia. In this concept review, the results of recent studies on CD200 and its inhibitory receptor, CD200R, are summarized and integrated to yield a model whereby CD200-CD200R interaction attenuates perifollicular inflammation, prevents HF-specific autoimmunity and may protect epidermal stem cells from autoimmune destruction. Further elucidation of the CD200-CD200R signaling pathway in cutaneous tissues may advance understanding of how immune homeostasis is established and maintained in the skin.
    Journal of Dermatological Science 04/2006; 41(3):165-74. · 3.34 Impact Factor
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    ABSTRACT: CD 200 is a widely expressed transmembrane glycoprotein that transmits an inhibitory signal after ligation of the structurally homologous CD 200-receptor-1 (CD 200 R1). Recently, we showed that CD 200 is expressed on keratinocytes and plays a role in protecting hair follicles from autoimmune attack. Here, we report the characterization of cell surface and mRNA expression of CD 200 R1 by cells of the murine epidermis. In addition, we report mRNA expression for other members of the CD 200 R-family (R2-R4) by quantitative real-time RT-PCR. Variable levels of CD 200 R1, R2, R3, and R4 mRNA were detected in bulk epidermal cell suspensions. Freshly isolated Langerhans cells (LC) preferentially expressed CD 200 R1. Consistent with an inhibitory role for CD 200:CD 200 R1 interaction, LC obtained from mice deficient in CD 200 (CD 200(-/-)) were in a heightened state of activation as compared with wild-type (CD 200(+/+)) cells. Freshly isolated dendritic epidermal T cells (DETC) expressed low levels of CD 200 R1, R2, and R3 mRNA, but they preferentially increased cell surface and mRNA expression of CD 200 R1 upon activation in vitro. In functional assays using sub-optimal CD3 signaling, immobilized CD 200 inhibited DETC proliferation and cytokine secretion. Collectively, these results suggest that CD 200:CD 200 R interactions may play a role in regulating both LC and DETC in cutaneous immune reactions.
    Journal of Investigative Dermatology 01/2006; 125(6):1130-8. · 6.37 Impact Factor
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    ABSTRACT: CD200 (OX-2) is a transmembrane glycoprotein that transmits an immunoregulatory signal through the CD200 receptor (CD200R) to attenuate inflammatory reactions and promote immune tolerance. CD200 expression in the skin has not been described previously. We now report that freshly isolated cells of the murine epidermis contain a subpopulation of major histocompatibility complex (MHC) class II-negative, CD3-negative keratinocytes that are CD200-positive. CD200 expression was accentuated in keratinocytes comprising the outer root sheath of the murine hair follicle (HF). When syngeneic skin grafts were exchanged between gender-matched wild-type (WT) and CD200-deficient C57BL/6 mice, significant perifollicular and intrafollicular inflammation was observed, eventually leading to the destruction of virtually all HF (alopecia) without significant loss of the CD200-negative grafts. Minimal and transient inflammation was observed in WT grafts, which persisted long term with hair. There was a 2-fold increase in graft-infiltrating T cells in CD200-deficient skin at 14 d. Alopecia and skin lesions were induced in CD200-deficient hosts by adoptive transfer of splenocytes from WT mice previously grafted with CD200-negative skin, but not from mice grafted with WT skin. Collectively, these results suggest that the expression of CD200 in follicular epithelium attenuates inflammatory reactions and may play a role in maintaining immune tolerance to HF-associated autoantigens.
    Journal of Investigative Dermatology 12/2004; 123(5):880-7. · 6.37 Impact Factor
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    ABSTRACT: During apoptotic cell death, biochemical processes modify self-proteins and create potential autoantigens. To maintain self-tolerance in the face of natural cell turnover, the immune system must prevent or control responses to apoptosis-associated autoantigens or risk autoimmunity. The molecular mechanisms governing this process remain largely unknown. Here, we show that expression of the immunoregulatory protein CD200 increases as murine dendritic cells (DCs) undergo apoptosis. We define CD200 as a p53-target gene and identify both p53- and caspase-dependent pathways that control CD200 expression during apoptosis. CD200 expression on apoptotic DCs diminishes proinflammatory cytokine production in response to self-antigens in vitro and is required for UVB-mediated tolerance to haptenated self-proteins in vivo. Up-regulation of CD200 may represent a novel mechanism, whereby immune reactivity to apoptosis-associated self-antigens is suppressed under steady state conditions.
    Blood 05/2004; 103(7):2691-8. · 9.78 Impact Factor
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    Blood 04/2004; 103(5):1969-71. · 9.78 Impact Factor
  • Biology of Blood and Marrow Transplantation 02/2004; 10:10-10. · 3.35 Impact Factor
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    ABSTRACT: We report the case of a t(14:18)(+) follicular lymphoma (FL) patient in long-term clinical remission after undergoing an allogeneic bone marrow transplantation (allo-BMT) from a human leukocyte antigen (HLA)-identical sibling donor who was the normal healthy carrier of a t(14:18)(+) B cell clone. Using real-time quantitative PCR (RQ-PCR) and gel electrophoresis, we document the temporal disappearance of the patient's t(14:18)(+) clone early post-transplant with the concomitant emergence and long-term persistence of the donor's t(14:18)(+) clone in the patient's peripheral blood. This report indicates that the use of PCR-based techniques to measure minimal residual disease in FL patients post-alloBMT should incorporate pretransplant screening of the donor for t(14;18). Furthermore, it suggests that healthy individuals with t(14:18) need not be excluded as donors for FL patients treated with allo-BMT.
    Bone Marrow Transplantation 06/2003; 31(10):947-9. · 3.47 Impact Factor
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    ABSTRACT: We report the case of a 59-year-old woman with Durie-Salmon stage IIIB IgGkappa multiple myeloma (MM), who presented 83 days after autologous hematopoietic stem cell transplant (HSCT) with multiple subcutaneous plasmacytomas. These lesions were confined exclusively to sites where the patient had sustained local trauma. The patient had no pre-transplant history of extramedullary disease and no evidence of plasma cells in the peripheral blood at any time throughout the course of her disease. This case represents the first report of refractory MM presenting as multiple subcutaneous plasmacytomas with specific tropism to sites of previous trauma. Selection of tumor cell subclones with unique chemokine receptor expression profiles that may explain this clinical observation is discussed.
    American Journal of Hematology 05/2003; 72(4):274-7. · 3.48 Impact Factor
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