Y. Shoenfeld, G. Zandman-Goddard, L. Stojanovich, M. Cutolo, H. Amital, Y. Levy, M. Abu-Shakra, O. Barzilai, Y. Berkun, M. Blank, J.F. de Carvalho, A. Doria, B. Gilburd, U. Katz, I. Krause, P. Langevitz, H. Orbach, V. Pordeus, M. Ram, E. Toubi and Y. Sherer
Y. Shoenfeld, M. Blank, M. Abu-Shakra, H. Amital, O. Barzilai, Y. Berkun, N. Bizzaro, B. Gilburd, G. Zandman-Goddard, U. Katz, I. Krause, P. Langevitz, I.R. Mackay, H. Orbach, M. Ram, Y. Sherer, E. Toubi and M.E. Gershwin
R.E. Voll, V. Urbonaviciute, M. Herrmann and J.R. Kalden
High mobility group box 1 is a nuclear protein participating in chromatin architecture and transcriptional regulation. When released from cells, HMGB1 can also act as a pro-inflammatory mediator or alarmin. Upon stimulation with lipopolysaccharides or tumor necrosis factor-alpha, HMGB1 is secreted from certain cells such as monocytes/macrophages and fosters inflammatory responses. In addition, HMGB1 is passively released from necrotic cells and mediates inflammation and immune activation. In contrast, during apoptotic cell death, nuclear HMGB1 gets tightly attached to hypo-acetylated chromatin and is not released into the extracellular milieu, thereby preventing an inflammatory response. There is accumulating evidence that extracellular HMGB1 contributes to the pathogenesis of many inflammatory diseases, including autoimmune diseases. Increased concentrations of HMGB1 have been detected in the synovial fluid of patients with rheumatoid arthritis. In animal models of RA, HMGB1 appears to be crucially involved in the pathogenesis of arthritis, since neutralization of HMGB1 significantly ameliorates the disease. Also, in the serum and plasma of patients with systemic lupus erythematosus we detected substantial amounts of HMGB1, which may contribute to the disease process. However, investigations of blood concentrations of HMGB1 and its relevance in human diseases are hindered by the lack of reliable routine test systems.
S. Fuchs, T. Feferman, R. Meidler, T. Brenner, O. Laub and M.C. Souroujon
Backgraound: Intravenous immunoglobulin administration has been beneficially used for the treatment of a variety of autoimmune diseases including myasthenia gravis, although its mode of action and active components have not yet been fully identified.
Objectives: To isolate from IVIg a disease-specific fraction involved in the therapeutic activity in myasthenia and to identify its properties and function.
Results: IVIg administration in experimental autoimmune MG results in suppression of disease that is accompanied by decreased Th1 cell and B cell proliferation. Chromatography of IVIg on columns of IgG from rats with EAMG or from MG patients resulted in depletion of the suppressive activity that IVIg has on rat EAMG. Moreover, the minute amounts of IgG fractions eluted from the EAMG or MG-specific columns retained the immunosuppressive activity of IVIg.
Conclusions: Our study supports the notion that the therapeutic effect of IVIg is mediated by a minor disease-specific immunoglobulin fraction that is present in IVIg and is essential for its therapeutic activity.
E. Toubi
Among the several mechanisms that play a role in maintaining peripheral self-tolerance is the existence of a unique CD4+CD25+ population of naturally occurring regulatory T cells, which actively prevent both the activation and the effector function of autoreactive T cells that have escaped different mechanisms of tolerance. Many studies have shown the benefit of targeting this cell population by restoring self-tolerance. Therapies that could possibly increase the suppressive ability of T regulatory cells were proven to improve the course of autoimmune diseases.
D. Buskila and P. Sarzi-Puttini