[Interferon-alpha: a key cytokine in systemic lupus erythematosus pathogenesis]

[Recombinant proteins or monoclonal antibodies: comparative properties and interest in systemic lupus erythematosus]

The emergence of biologic therapies, such as monoclonal antibodies or recombinant fusion proteins, have revolutionized the management of autoimmune disorders, in particular rheumatoid arthritis. These biologic agents have been engineered to deplete key cellular populations or to block cytokines or molecules involved in the activation and/or the differentiation of immune cells, such as T cells or B cells. In systemic lupus erythematosus (SLE), a monoclonal antibody directed against the B-cell activating factor of the TNF family (BAFF or BLyS), belimumab, has demonstrated its efficacy in large, randomized and placebo-controlled studies, whereas rituximab, a monoclonal antibody directed against the CD20 expressed by B cells, failed to achieve his primary endpoint in renal and non-renal SLE. Studies on the safety and the efficacy of monoclonal antibodies or recombinant fusion proteins directed against other key molecules involved in the pathogenesis of SLE are ongoing.

[Telomeres and telomerase: relevance and future prospects in systemic lupus erythematosus]

Telomeres are specialized structures that cap and protect the end of chromosomes. Telomeres progressively shorten after each cellular division unless an enzyme, the telomerase, counteracts. Telomeres are implicated in cellular senescence, acting like a biological clock. Telomere length and telomerase activity are important in the physiopathology of cancer. In the past years, research has focused on them in order to find new therapeutic targets. Yet, oxidative stress, inflammation and increased leucocytes renewal are major environmental factors associated with telomeres shortening acceleration and thus in concordance with biological age. Thus, telomeric erosion induces cell apoptosis; indeed, apoptotic cell clearance is impaired in systemic lupus. Considering these elements and data resulting from oncology, telomere/telomerase couple was studied during the last decade in systemic lupus erythematosus. The objective was to know if this couple could have an implication in the physiopathology of this disease. A systematic review of literature is proposed about telomere and/or telomerase in systemic lupus erythematosus in order to discuss their physiopathological implication. Among 273 tested patients, telomere seems to be eroded and telomerase activity insufficiently increased but correlated to the activity of the disease. The analysis of telomere length and telomerase activity could be useful as prognosis factor or disease activity index. Telomere erosion could reflect an accelerated replicative senescence of the immune system. The role of the regulator T lymphocytes has not yet been precised. Standardized studies on larger population could be realized in systemic lupus and open new avenues of research and/or therapy based upon the telomere/telomerase biology.

Interferon-alpha causes neuronal dysfunction in encephalitis

Interferon-alpha (IFNalpha) is a pleomorphic cytokine produced by nucleated cells in response to viral infection. In patients, treatment with IFNalpha has side effects including cognitive impairment resembling subcortical dementia, which is a hallmark of human immunodeficiency virus (HIV)-associated dementia (HAD). IFNalpha is increased in the CSF of HAD patients compared with HIV patients without dementia. In this study, blocking IFNalpha in a HIV encephalitis (HIVE) mouse model with intraperitoneal injections of IFNalpha neutralizing antibodies (NAbs) significantly improved cognitive function compared with untreated or control antibody-treated HIVE mice during water radial arm maze behavioral testing. Treatment with IFNalpha NAbs significantly decreased microgliosis and prevented loss of dendritic arborization in the brains of HIVE mice. Furthermore, treatment of primary neuron cultures with IFNalpha resulted in dose-dependent loss of dendritic arborization that was blocked with IFNalpha NAb treatment and partially blocked with NMDA antagonists [AP5 and MK801 (dizocilpine maleate)] indicating glutamate signaling is involved in IFNalpha-mediated neuronal damage. These results show that IFNalpha has a major role in the pathogenesis of HIVE in mice and is likely important in the development neurocognitive dysfunction in humans with HIV. Blocking IFNalpha could be important in improving cognitive and pathological developments in HAD patients and may be clinically important in other neuroinflammatory diseases as well.