Intravenous polyclonal human immunoglobulins in multiple sclerosis

Immunomodulators and immunosuppressants for progressive multiple sclerosis: a network meta‐analysis

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

We will perform a network meta‐analysis to assess the relative effectiveness and safety of immunomodulatory and immunosuppressive treatments for people with multiple sclerosis in progressive forms of the condition.

[A treatment of neuromyelitis optica (Devic's disease) during pregnancy]

Neuromyelitis optica (Devic's disease) is an inflammatory demyelinating disease of the central nervous system that mainly affects spinal cord, optic nerve and brain regions with high aquaporin 4 antigen expression. This is a severe autoimmune disease caused by autoantibodies directed against aquaporin 4 and associated with high morbidity and mortality. Unlike other inflammatory conditions such as multiple sclerosis or rheumatoid polyarthritis, pregnancy does not seem to influence the activity of neuromyelitis optica, hence the need for a thorough treatment during pregnancy. Corticosteroid therapy is the treatment of choice for neuromyelitis optica during pregnancy. Other treatments may also be used including rituximab, some immunosuppressive agents and immunoglobulins. Immunosuppressive treatment or rituximab is recommended when the long-term corticosteroid treatment is contraindicated, in case of inefficiency or if side effects are intolerable. Immunoglobulins are administered to patients with serious outbreaks of neuromyelitis optica which do not respond to bolus methylprednisolone. Immunoglobulins alone can also be continued at a dose of 0.4 g/kg/day for 6-8 weeks until delivery. Plasmapheresis is also a good alternative to bolus methylprednisolone when outbreaks are extremely severe.

The Production Processes and Biological Effects of Intravenous Immunoglobulin

Immunoglobulin is a highly diverse autologous molecule able to influence immunity in different physiological and diseased situations. Its effect may be visible both in terms of development and function of B and T lymphocytes. Polyclonal immunoglobulin may be used as therapy in many diseases in different circumstances such as primary and secondary hypogammaglobulinemia, recurrent infections, polyneuropathies, cancer, after allogeneic transplantation in the presence of infections and/or GVHD. However, recent studies have broadened the possible uses of polyclonal immunoglobulin showing that it can stimulate certain sub-populations of T cells with effects on T cell proliferation, survival and function in situations of lymphopenia. These results present a novel and considerable impact of intravenous immunoglobulin (IVIg) treatment in situations of severe lymphopenia, a situation that can occur in cancer patients after chemo and radiotherapy treatments. In this review paper the established and experimental role of polyclonal immunoglobulin will be presented and discussed as well as the manufacturing processes involved in their production.

Treatment of progressive multifocal leukoencephalopathy-immune reconstitution inflammatory syndrome with intravenous immunoglobulin in a patient with multiple sclerosis treated with fingolimod after discontinuation of natalizumab

We report a case of progressive multifocal leukoencephalopathy-immune reconstitution inflammatory syndrome in a multiple sclerosis (MS) patient 3.5 months after fingolimod commencement and 4.5 months after natalizumab (NTZ) cessation. Three cerebrospinal fluid analyses were required before a definitive diagnosis of progressive multifocal leukoencephalopathy was reached. Intravenous immunoglobulin (IVIG) was subsequently given as the sole MS treatment along with mirtazapine and mefloquine. There has been improvement and subsequent clinical stabilization. The notable features are the difficult timing of fingolimod commencement in the context of previous NTZ therapy, the role of repeated cerebrospinal fluid John Cunningham virus analyses in progressive multifocal leukoencephalopathy diagnosis, and the role of IVIG.

Treatment of spinal cord injury with intravenous immunoglobulin G: preliminary evidence and future perspectives

Neuroinflammation plays an important role in the secondary pathophysiological mechanisms of spinal cord injury (SCI) and can exacerbate the primary trauma and thus worsen recovery. Although some aspects of the immune response are beneficial, it is thought that leukocyte recruitment and activation in the acute phase of injury results in the production of cytotoxic substances that are harmful to the nervous tissue. Therefore, suppression of excessive inflammation in the spinal cord could serve as a therapeutic strategy to attenuate tissue damage. The immunosuppressant methylprednisolone has been used in the setting of SCI, but there are complications which have attenuated the initial enthusiasm. Hence, there is interest in other immunomodulatory approaches, such as intravenous Immunoglobulin G (IVIg). Importantly, IVIg is used clinically for the treatment of several auto-immune neuropathies, such as Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy (CIPD) and Kawasaki disease, with a good safety profile. Thus, it is a promising treatment candidate for SCI. Indeed, IVIg has been shown by our team to attenuate the immune response and result in improved neurobehavioral recovery following cervical SCI in rats through a mechanism that involves the attenuation of neutrophil recruitment and reduction in the levels of cytokines and cytotoxic enzymes Nguyen et al. (J Neuroinflammation 9:224, 2012). Here we review published data in the context of relevant mechanisms of action that have been proposed for IVIg in other conditions. We hope that this discussion will trigger future research to provide supporting evidence for the efficiency and detailed mechanisms of action of this promising drug in the treatment of SCI, and to facilitate its clinical translation.

The effects of intravenous immunoglobulin on cerebral ischemia in rats: An experimental study

Stroke is one of the major reasons of death in the United States and related to adult disability. Despite aggressive research, the treatment approaches of stroke still remains a major clinical problem. Intravenous immunoglobulin (IVIg) is a polyspecific Ig G preparation obtained from plasma of several thousand healthy people (donors). IVIg is an important treatment approach and used for several disorders. The aim of this study was to investigate the potentially beneficial effects of IVIg therapy in experimentally induced ischemia in middle cerebral artery occlusion (MCAo) models of rats. A total of 30 adult male Sprague Dawley rats were used. The rats were divided into two equal groups, each consisting of 15 randomly selected rats: control group (n = 15) and IVIg group (n = 15). Intraluminal filament method was used for establishment of cerebral ischemia. Intraluminal filament was withdrawn after 2 h of MCAo and reperfusion started again and passed to therapeutic stages for all the groups. Physiologic saline solution of 0.5 ml/kg was administered to the control group and 400 mg/kg IVIg was given to the IVIg group rats intravenously. In neurological evaluation, the worst score was determined as 3 and the best score as 0. After routine process, the brain tissue was prepared histopathological investigation. The IVIg group showed significantly better recovery with respect to the control group by neurological examination. The observation of specimens obtained from IVIg groups showed that findings correlate with grade 1 and -2 histopathologically. Nevertheless, ischemic amendments were observed to comply with grade 3 in ischemic areas in control group. IVIg therapy can be used in the treatment of ischemic stroke patients.

Immunization with a peptide of Semliki Forest virus promotes remyelination in experimental autoimmune encephalomyelitis

Remyelination is one of the elusive topics in treatment of multiple sclerosis (MS). Our previous studies have shown that Semliki Forest virus (SFV)-infected δ-knock-out (KO) mice did not exhibit the extensive remyelination, seen in wild type (WT) B6 mice, after viral clearance and demyelination. The Remyelination in SFV-infected WT mice started on day 15 and was completed by day 35 post-infection (pi), whereas the KO mice remained partially demyelinated through day 42 pi. Treatment with E2 peptide2 in incomplete Freund's adjuvant (IFA), resulted in higher antibody production and earlier remyelination in SFV-infected KO (day 28 pi), than WT mice. This finding suggested that anti-E2 peptide2 antibody could play a part in remyelination. In the current study, the effect of E2 peptide2 treatment was evaluated in the experimental autoimmune encephalomyelitis (EAE) model. Mice with established EAE were treated with E2 peptide2 in IFA to develop antibody. Treated EAE mice made significantly higher anti-E2 peptide2 antibody than untreated EAE group. Average clinical disease scores were significantly lower in peptide treated compared to untreated EAE mice. Furthermore, histopathological and immunohistochemical studies demonstrated increased remyelinating areas and higher number of activated oligodendrocytes and astrocytes, in treated compared to untreated EAE groups. Moreover, the anti-E2 peptide2 antibody showed higher binding to the myelinated areas of treated than untreated EAE mice. We conclude that treatment with, or antibody to, SFV E2 peptide2 triggers some mechanism that promotes remyelination.

Immunoglobulin G (IgG) attenuates neuroinflammation and improves neurobehavioral recovery after cervical spinal cord injury

Background

Evidence suggests that the inflammatory events in the acute phase of spinal cord injury (SCI) exacerbate the initial trauma to the cord leading to poor functional recovery. As a result, minimizing the detrimental aspects of the inflammatory response after SCI is a promising treatment strategy. In this regard, immunoglobulin G (IgG) from pooled human serum is a promising treatment candidate. Due to its putative, though poorly characterized immuno-modulatory effects, IgG has been used clinically to treat neuroinflammatory disorders such as Guillain-Barré syndrome, but its effects in neurotrauma remain largely unexplored.

Methods

This study examines the potential neuroprotective effects of IgG in a well-characterized cervical model of SCI. Female Wistar rats were subject to moderate-severe clip compression injury at the C7-T1 level. IgG (0.4 g/kg) or saline was injected intravenously to randomly selected animals at 15 min post SCI. At several time points post SCI, biochemical assays, histology and immunohistochemistry analyses, and neurobehavioral assessments were used to examine the neuroprotective effects of IgG at the molecular, cellular, and neurobehavioral levels.

Results

We found that intravenous treatment of IgG following acute clip-compression SCI at C7-T1 significantly reduced two important inflammatory cytokines: interleukin (IL)-1β and IL-6. This early reduction in pro-inflammatory signaling was associated with significant reductions in neutrophils in the spinal cord and reductions in the expression of myeloperoxidase and matrix metalloproteinase-9 in the injured spinal cord at 24 h after SCI. These beneficial effects of IgG were associated with enhanced tissue preservation, improved neurobehavioral recovery as measured by the BBB and inclined plane tests, and enhanced electrophysiological evidence of central axonal conduction as determined by motor-evoked potentials.

Conclusion

The findings from this study indicate that IgG is a novel immuno-modulatory therapy which shows promise as a potential treatment for SCI.

Current therapeutic recommendations in multiple sclerosis

Recent clinical studies in multiple sclerosis have provided new data on glatiramer acetate, interferon-beta preparations and natalizumab, which will have important implications for optimising patient care. Once a diagnosis has been made with confidence, early initiation of immunotherapy is warranted because of the presence of continuous inflammatory disease activity. Approval for therapy in patients with a clinically isolated syndrome has been granted to several first-line treatments, and most recently to glatiramer acetate. The utility of systematic frequent MRI monitoring of disease activity and response to therapy is not yet clearly established. Treatment efficacy after initiating therapy at the first demyelinating episode has to be followed carefully and re-evaluated whenever necessary. The occurrence of further relapses, confirmed disability progression or MRI evidence of persistent or aggravated disease activity would be regarded as evidence for an inadequate treatment response. However, limitations of clinical scores in faithfully reflecting disease activity at all times, as well as uncertainties about the discriminatory capacity of surrogate measures such as MRI, need to be clarified before clear-cut recommendations on treatment failure can be advocated. Escalation therapy is reserved for patients presenting with 'aggressive disease', which can be operationally defined as the occurrence of two severe relapses within twelve months, together with either MRI evidence for persistent disease activity or a two-point progression of disability on the EDSS.

Regulation of Fcgamma receptors and immunoglobulin G-mediated phagocytosis in mouse microglia

As resident macrophages in the CNS, microglia can transform from a surveillance state to an activated phenotype in response to brain injury. During this transition microglia become highly capable phagocytic cells. Invading pathogens undergo opsonization with immunoglobulins and microglia recognize these opsonized pathogens through interaction with their cognate F(c) receptors. In mice, both FcgammaRI and FcgammaRIIb receptors are involved in IgG-mediated phagocytosis of opsonzied pathogens. At sites of inflammation, microglial activity is regulated by T-cell derived cytokines. Here we first investigated the effects of IFN-gamma, IL-4, IL-13 and GM-CSF on expression of FcgammaRI and FcgammaRIIb mRNA levels in both primary microglia and microglial cell line N9. Using quantitative real-time PCR we show that IFN-gamma induced a 4-fold increase in the mRNA level of FcgammaRI but did not induce changes in FcgammaRIIb expression. IL-4 and IL-13 induced approximately 2-fold increases in expression of FcgammaRIIb mRNA, but had no effect on FcgammaRI expression. GM-CSF increased both FcgammaRI and FcgammaRIIb mRNA expression. We then characterized the ability of these same cytokines to regulate phagocytosis of immune complexes composed of IgG and the bacteria Staphylococcus aureus. IFN-gamma and GM-CSF both induced approximately 2-fold increases in IgG-mediated phagocytosis whereas IL-4 and IL-13 both decreased IgG-mediated phagocytosis by about one-third. None of the cytokines influenced basal levels of phagocytosis. These findings demonstrate a highly selective cytokine-induced regulation of both phagocytosis-related Fcgamma receptor subtypes and IgG-mediated phagocytosis itself in microglia. This selective regulation has implications for our understanding of the pathophysiology of CNS infection and autoimmune disease.

Neuroprotection in stroke by complement inhibition and immunoglobulin therapy

Activation of the complement system occurs in a variety of neuroinflammatory diseases and neurodegenerative processes of the CNS. Studies in the last decade have demonstrated that essentially all of the activation components and receptors of the complement system are produced by astrocytes, microglia, and neurons. There is also rapidly growing evidence to indicate an active role of the complement system in cerebral ischemic injury. In addition to direct cell damage, regional cerebral ischemia and reperfusion (I/R) induces an inflammatory response involving complement activation and generation of active fragments, such as C3a and C5a anaphylatoxins, C3b, C4b, and iC3b. The use of specific inhibitors to block complement activation or their mediators such as C5a, can reduce local tissue injury after I/R. Consistent with therapeutic approaches that have been successful in models of autoimmune disorders, many of the same complement inhibition strategies are proving effective in animal models of cerebral I/R injury. One new form of therapy, which is less specific in its targeting of complement than monodrug administration, is the use of immunoglobulins. Intravenous immunoglobulin (IVIG) has the potential to inhibit multiple components of inflammation, including complement fragments, pro-inflammatory cytokine production and leukocyte cell adhesion. Thus, IVIG may directly protect neurons, reduce activation of intrinsic inflammatory cells (microglia) and inhibit transendothelial infiltration of leukocytes into the brain parenchyma following an ischemic stroke. The striking neuroprotective actions of IVIG in animal models of ischemic stroke suggest a potential therapeutic potential that merits consideration for clinical trials in stroke patients.

Activation of natural regulatory T cells by IgG Fc-derived peptide "Tregitopes"

We have identified at least 2 highly promiscuous major histocompatibility complex class II T-cell epitopes in the Fc fragment of IgG that are capable of specifically activating CD4(+)CD25(Hi)FoxP3(+) natural regulatory T cells (nT(Regs)). Coincubation of these regulatory T-cell epitopes or "Tregitopes" and antigens with peripheral blood mononuclear cells led to a suppression of effector cytokine secretion, reduced proliferation of effector T cells, and caused an increase in cell surface markers associated with T(Regs) such as FoxP3. In vivo administration of the murine homologue of the Fc region Tregitope resulted in suppression of immune response to a known immunogen. These data suggest that one mechanism for the immunosuppressive activity of IgG, such as with IVIG, may be related to the activity of regulatory T cells. In this model, regulatory T-cell epitopes in IgG activate a subset of nT(Regs) that tips the resulting immune response toward tolerance rather than immunogenicity.