Immune responses to JC virus in patients with multiple sclerosis treated with natalizumab: a cross-sectional and longitudinal study.
ABSTRACT Natalizumab is used to prevent relapses and progression of disability in patients with multiple sclerosis but has been associated with progressive multifocal leukoencephalopathy (PML). We aimed to better understand the associations between JC virus, which causes PML, and natalizumab treatment.
We prospectively assessed patients with multiple sclerosis who started treatment with natalizumab. Blood and urine samples were tested for the presence of JC virus DNA with quantitative real-time PCR before treatment and at regular intervals after treatment onset for up to 18 months. At the same timepoints, by use of proliferation and enzyme-linked immunospot assays, the cellular immune responses against JC virus, Epstein-Barr virus, cytomegalovirus, myelin oligodendrocyte glycoprotein, and myelin oligodendrocyte basic protein (MOBP) were assessed. Humoral immune response specific to JC virus was assessed with an enzyme immunoassay. The same experiments were done on blood samples from patients with multiple sclerosis before and 10 months after the start of interferon beta treatment.
We assessed 24 patients with multiple sclerosis who received natalizumab and 16 who received interferon beta. In patients treated with natalizumab, JC virus DNA was not detected in the blood at any timepoint. However, JC virus DNA was present in the urine of six patients and in most of these patients the concentrations of JC virus DNA were stable over time. Compared with pretreatment values, the cellular immune response was increased to cytomegalovirus at 6 months, to JC virus at 1, 9, and 12 months, and to Epstein-Barr virus and MOBP at 12 months. Humoral responses remained stable. There were no increases in cellular immune responses specific to the viruses or myelin proteins in the 16 patients treated with interferon beta.
Natalizumab increases cellular immune responses specific to viruses and myelin proteins in the peripheral blood after 1 year, without evidence of viral reactivation.
Swiss National Foundation, Swiss Society for Multiple Sclerosis, and Biogen Dompé.
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ABSTRACT: Natalizumab-induced progressive multifocal leukoencephalopathy appears to be unleashed by complex interactions between viral and immunological host factors leading the latent form of JC virus to become pathogenic. Positive anti-JC virus antibody status, prior use of immunosuppressants, and increasing duration of natalizumab treatment have been proposed as risk factors for progressive multifocal leukoencephalopathy in multiple sclerosis patients, but while they may help to identify the most appropriate patients for natalizumab, their use have some limitations. Therefore, a large body of studies is ongoing to identify alternative, reliable immunological markers capable to improve the safety and efficacy of therapy, and to guide tailored clinical decisions. Copyright © 2014. Published by Elsevier B.V.Journal of Neuroimmunology 11/2014; 277(1-2):6-12. DOI:10.1016/j.jneuroim.2014.10.011 · 2.79 Impact Factor
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ABSTRACT: The risk of developing progressive multifocal leukoencephalopathy (PML), as a consequence of infection/reactivation with JC virus (JCV), is consistent in natalizumab-treated multiple sclerosis (MS) patients, with 430 cases of PML reported so far. The risk of PML is higher in JCV seropositive patients, and it is recommended that only MS patients without JCV antibodies should be enrolled in the treatment postulating that they do not have JCV infection.We have studied forty-two natalizumab-treated MS patients, and urine and blood were collected monthly for up to 60 months. JCV and BK virus (BKV) DNA presence was verified using quantitative real-time PCR assays, and serum anti-JCV antibodies were measured with the Stratify and/or Stratify DxSelect tests.JCV and BKV DNA were not found in the blood samples, whereas they were found at least once in the urine of 21 of 42 (50 %) and of 25/42 (59.5 %) patients, respectively. JCV DNA urinary shedding increased up to month 24 of natalizumab treatment (45.2 %), and the effect of time was significant for JCV (p = 0.04), but not for BKV (p = 0.39). JCV viruria and seropositivity did not completely correlate, since three patients shedding JCV DNA in the urine were seronegative according to the serological tests.The results indicated that natalizumab therapy may increase the rate of JCV urinary shedding. Additionally, we confirmed that the identification of JCV carriers cannot solely rely on serological tests, but sensitive methods for viral DNA detection should be adopted to more precisely identify the truly JCV uninfected cases.Journal of NeuroVirology 07/2014; DOI:10.1007/s13365-014-0268-0 · 3.32 Impact Factor
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ABSTRACT: Multiple sclerosis (MS) is an immune-mediated disease where T cells are thought to initiate an inflammatory reaction in the brain and spinal cord, resulting in demyelination and axonal pathology. Interfering with the activation and recruitment of immune cells reduces disease activity in MS. We review the mechanism of action and treatment effects of natalizumab and fingolimod, which interfere with the recruitment of pathogenic immune cells in MS. Fingolimod blocks the egress of activated lymphocytes from lymph nodes by binding to the sphingosine-1-phosphate (S1P) receptor 1, but may also have effects on S1P receptor-expressing cells within the central nervous system (CNS). Natalizumab reduces the migration of lymphocytes to the CNS by binding to the α4 integrin very late antigen 4. Fingolimod and natalizumab also have other effects, but these are less well understood. Both treatments are efficacious in reducing relapses, accumulation of persisting disability and magnetic resonance imaging disease activity. Both treatments are safe and well tolerated in the majority of patients, but due to a potential for serious side effects they are licensed as second line therapies or for treatment of highly active MS in most European countries. We conclude that fingolimod and natalizumab have well known effects on the migration of immune cells in MS and have substantial effects on disease activity in relapsing−remitting MS. Additional effects on disease progression, potential effects within the CNS and other effects on immune cells are still being clarified.European Journal of Neurology 01/2015; DOI:10.1111/ene.12668 · 3.85 Impact Factor