Refractory anti-NMDAR encephalitis successfully treated with bortezomib and associated movements disorders controlled with tramadol: a case report with literature review

Lymphocytes in autoimmune encephalitis: Pathogenesis and therapeutic target

Autoimmune encephalitis (AE) is an inflammatory disease of the central nervous system characterized by the production of various autoimmune antibodies targeting neuronal proteins. The pathogenesis of AE remains elusive. Accumulating evidence suggests that lymphocytes, particularly B and T lymphocytes, play an integral role in the development of AE. In the last two decades, autoimmune neural antibodies have taken center stage in diagnosing AE. Recently, increasing evidence has highlighted the importance of T lymphocytes in the onset of AE. CD4+ T cells are thought to influence disease progression by secreting associated cytokines, whereas CD8+ T cells exert a cytotoxic role, causing irreversible damage to neurons mainly in patients with paraneoplastic AE. Conventionally, the first-line treatments for AE include intravenous steroids, intravenous immunoglobulin, and plasma exchange to remove pathogenic autoantibodies. However, a minority of patients are insensitive to conventional first-line treatment protocols and suffer from disease relapse, a condition referred to as refractory AE. In recent years, new treatments, such as rituximab or CAAR-T, which target pathogenic lymphocytes in patients with AE, have offered new therapeutic options for refractory AE. This review aims to describe the current knowledge about the function of B and T lymphocytes in the pathophysiology of AE and to summarize and update the immunotherapy options for treating this disease.

Bortezomib-induced peripheral neuropathy: Clinical features, molecular basis, and therapeutic approach

Bortezomib is the first-line standard and most effective chemotherapeutic for multiple myeloma; however, bortezomib-induced peripheral neuropathy (BIPN) severely affects the chemotherapy regimen and has long-term impact on patients under maintenance therapy. The pathogenesis of BIPN is poorly understood, and basic research and development of BIPN management drugs are in early stages. Besides chemotherapy dose reduction and regimen modification, no recommended prevention and treatment approaches are available for BIPN apart from the International Myeloma Working Group guidelines for peripheral neuropathy in myeloma. An in-depth exploration of the pathogenesis of BIPN, development of additional therapeutic approaches, and identification of risk factors are needed. Optimizing effective and standardized BIPN treatment plans and providing more decision-making evidence for clinical diagnosis and treatment of BIPN are necessary. This article reviews the recent advances in BIPN research; provides an overview of clinical features, underlying molecular mechanisms, and therapeutic approaches; and highlights areas for future studies.

Therapeutic plasma exchange in anti-N-methyl-D-aspartate receptor encephalitis

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is the most commonly identified cause of autoimmune encephalitis. Therapeutic plasma exchange has been increasingly employed to treat this disease. This expansion is a consequence of improved techniques and apheresis instruments, as well as the recognition of its applicability in neurological diseases. However, several aspects of treatment remain incompletely clarified, and treatment strategies are still heterogeneous, especially with regard to therapeutic plasma exchange in anti-NMDAR encephalitis. This review provides an overview of the use of therapeutic plasma exchange including the principle and mechanisms, the evidence, initial time, efficiency and complications in anti-NMDAR encephalitis.

Status dystonicus in adult patients with anti-N-methyl-D-aspartate-acid receptor encephalitis

OBJECTIVE

Status dystonicus (SD) is a severe movement disorder (MD) and has rarely been recognized in anti-N-methyl-D-aspartate-acid receptor (NMDAR) encephalitis, particularly in adult patients. We aim to explore the clinical characteristics and outcome of SD in anti-NMDAR encephalitis.

METHODS

Patients with anti-NMDAR encephalitis admitted to Xuanwu Hospital from July 2013 to December 2019 were prospectively enrolled. SD was diagnosed based on the patients' clinical manifestations and video EEG monitoring. Outcome was evaluated 6 and 12 months after enrollment using the modified Ranking Scale (mRS).

RESULTS

A total of 172 patients with anti-NMDAR encephalitis, including 95 males (55.2%) and 77 females (44.8%) with a median age of 26 years (interquartile range 19 to 34) were enrolled. Eighty patients (46.5%) presented with movement disorder (MD), 14 of whom suffered from SD, which manifested as chorea (14/14, 100%), orofacial dyskinesia (12/14, 85.7%), generalized dystonia (8/14, 57.1%), tremor (8/14, 57.1%), stereotypies (5/14, 35.7%), and catatonia (1/14, 7.1%) of the trunk and limbs. All SD patients exhibited disturbed consciousness and central hypoventilation, requiring intensive care. SD patients also had high cerebrospinal fluid NMDAR antibody titers, a higher proportion of ovarian teratoma, higher mRS scores upon enrollment, longer duration to recover, and poorer outcomes at 6 (P < 0.05) but not at 12 months as compared to non-SD patients.

CONCLUSION

SD is not uncommon in anti-NMDAR encephalitis patients and relates to the severity and worse short-term outcome of the anti-NMDAR encephalitis. Early recognition of SD and timely treatment is important to shorten the time needed for recuperation.

Case report: Anti-NMDA receptor encephalitis manifesting as rapid weight loss and abnormal movement disorders with alternating unilateral ptosis and contralateral limb tremor

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, associated with immunoglobulin G (IgG) autoantibodies against the GluN1 subunit of the NMDAR, is one of the most common types of autoimmune encephalitis. In patients with anti-NMDAR encephalitis, movement disorders (MDs) are often frequent, mainly presenting as facial dyskinesias and stereotyped movements. The alternating clinical manifestation of limb tremor with unilateral ptosis is rare. Here, we report an interesting case of a 22-year-old woman with rapid weight loss presenting with staged dyskinesia. Interestingly, she typically showed persistent tremor of the right upper limb, which would stop when her left upper eyelid drooped uncontrollably, a phenomenon that lasted for a few seconds, followed by automatic upper eyelid lift and continued persistent tremor of the upper limb. Moreover, it was fortunate to find anti-NMDAR antibodies in her cerebrospinal fluid (CSF), which indicated the patient had anti-NMDAR encephalitis. And abnormal apparent diffusion coefficient (ADC) hyperintense signals on the left midbrain interpeduncular fossa explained this manifestation of focal neurological deficit. After the systematic administration of immunotherapy (intravenous immunoglobulin, IVIG), steroid pulse therapy, and symptomatic treatment, the initial symptoms were significantly relieved except for limb tremor. The MDs were becoming less visible for the next six months under topiramate prescriptions. Noteworthy, there are no specific MD phenotypes in anti-NMDAR encephalitis. We describe the young women with unique MDs and rapid weight loss to help us get a more comprehensive understanding of anti-NMDAR encephalitis.

Recent research on immunotherapy for anti-N-methyl-D-aspartate receptor encephalitis

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a central nervous system disease characterized by neurological and psychiatric symptoms. Immunotherapy is the basic treatment for this disease, including first- and second-line therapies for the acute stage and the long-course therapy for the chronic stage. Anti-NMDAR encephalitis often has a good prognosis, but some patients may still have neurological dysfunction due to poor response to current immunotherapy. In addition, the adverse reactions and economic burden of drugs are practical problems in clinical practice. To solve the above problems, continuous improvements have been made in immunotherapy regimens in terms of dose, route of administration, and course of treatment, and some new immunotherapy drugs have emerged. This article reviews the recent research on immunotherapy for anti-NMDAR encephalitis.

Immunotherapy for Refractory Autoimmune Encephalitis

Autoimmune encephalitis (AE) is an immune-mediated disease involving the central nervous system, usually caused by antigen-antibody reactions. With the advent of autoantibody-associated diseases, AE has become a hot research frontier in neuroimmunology. The first-line conventional treatments of autoimmune encephalitis consist of steroids, intravenous immunoglobulin (IVIG), plasma exchange (PLEX), and second-line therapy includes rituximab. Despite considerable research and expanding clinical experience, current treatments are still ineffective for a significant number of patients. Although there is no clear consensus, clinical trial evidence limited, and the level of evidence for some of the drugs based on single reports, third-line therapy is a viable alternative for refractory encephalitis patients. With the current rapid research progress, a breakthrough in the treatment of AE is critical. This article aims to review the third-line therapy for refractory AE

Contemporary advances in anti-NMDAR antibody (Ab)-mediated encephalitis

The study of antibody (Ab)-mediated encephalitis has advanced dramatically since the discovery of antibodies directed against the N-methyl-D-aspartate receptor (NMDAR) in association with a unique neuro-psychiatric syndrome, over a decade-and-a-half ago. Anti-NMDAR Ab-mediated encephalitis now represents the most well characterised form of autoimmune encephalitis. The disease most commonly manifests in young women, but all ages and both sexes can be affected. Autoantibodies may arise in the context of two well-recognised disease triggers in a proportion of patients, and ultimately facilitate NMDAR displacement from synapses. Various CSF cytokines, chemokines, and other molecules have been explored as candidate biomarkers but are limited in sensitivity and specificity. The clinical spectrum is diverse, with evolution and a combination of neuro-psychiatric abnormalities at disease nadir common. Anti-NMDAR Ab-mediated encephalitis is immunotherapy responsive, and a near-majority ultimately acquire a broadly favourable clinical outcome. The diagnosis, and more particularly, the management of the disease can still hold considerable challenges. Moreover, well-defined biomarkers remain elusive. The present review will therefore delineate pathogenic and clinical advances to date in anti-NMDAR antibody-mediated encephalitis.

Immunomodulation in the acute phase of autoimmune encephalitis

Autoimmune encephalitides constitute an emerging group of diseases for which the diagnosis and management may be challenging, and are usually associated with antibodies against neuroglial antigens used as biomarkers. In this review, we aimed to clarify the diagnostic approach to patients with encephalitis of suspected autoimmune origin in order to initiate early immunotherapy, and to summarize the evidence of current immunotherapies and alternative options assessed for refractory cases. Currently, the general therapeutic approach consists of steroids, IVIG, and/or plasma exchange as first-line medications, which should be prescribed once a diagnosis of possible autoimmune encephalitis is established. For patients not responding to these treatments, rituximab and cyclophosphamide are used as second-line immunotherapy. Additionally, alternative therapies, chiefly tocilizumab and bortezomib, have been reported to be useful in particularly refractory cases. Although the aforementioned approach with first and second-line immunotherapy is widely accepted, the best therapeutic strategy is still unclear since most available evidence is gathered from retrospective non-controlled studies. Moreover, several predictors of good long-term prognosis have been proposed such as response to first-line therapies, modified Rankin score lesser than 4 at the worst neurologic status, no need for admission in intensive care unit, and early escalation to second-line immunotherapy. Thus, the lack of solid evidence underlines the necessity of future well-conducted trials addressing both the best therapeutic regimen and the outcome predictors, but since autoimmune encephalitides have a relatively low incidence, international collaborations seem imperative to reach a reasonable study population size.

Treatment Options in Refractory Autoimmune Encephalitis

Autoimmune encephalitis represents a potentially treatable immune-mediated condition that is being more frequently recognized. Prompt immunotherapy is a key factor for the management of autoimmune encephalitis. First-line treatments include intravenous steroids, plasma exchange, and intravenous immunoglobulins, which can be combined in most severe cases. Rituximab and cyclophosphamide are administered as second-line agents in unresponsive cases. A minority of patients may still remain refractory, thus representing a major clinical challenge. In these cases, treatment strategies are controversial, and no guidelines exist. Treatments proposed for refractory autoimmune encephalitis include (1) cytokine-based drugs (such as tocilizumab, interleukin-2/basiliximab, anakinra, and tofacitinib); (2) plasma cell-depleting agents (such as bortezomib and daratumumab); and (3) treatments targeting intrathecal immune cells or their trafficking through the blood-brain barrier (such as intrathecal methotrexate and natalizumab). The efficacy evidence of these drugs is mostly based on case reports or small case series, with few reported controlled studies or systematic reviews. The aim of the present review is to summarize the current evidence and related methodological issues in the use of these drugs for the treatment of refractory autoimmune encephalitis.

Bortezomib in autoimmune hemolytic anemia and beyond

Bortezomib is a first-in-class, potent, selective and reversible proteasome inhibitor approved for the treatment of multiple myeloma (MM) and relapsed/refractory mantle cell lymphoma. In these diseases, bortezomib targets plasma cells and lymphocytes reducing tumor burden. Recently, preclinical evidence highlighted its efficacy in reducing long-lived plasma cells responsible of autoantibodies production in several models of autoimmune conditions. These findings paved the way to a number of experiences of bortezomib use in patients with various autoimmune conditions, including autoimmune hemolytic anemia (AIHA). The latter is a nice model of autoimmunity in hematology and is caused by the production of autoantibodies against erythrocytes resulting in various degrees of hemolytic anemia. AIHA is classified in warm and cold forms according to the thermal characteristics of the autoantibody, and first-line treatment mainly relies on steroids for warm cases and the anti-CD20 rituximab for cold ones. Relapsed/refractory cases are still an unmet need, and bortezomib has been proposed in this setting with intriguing efficacy. In this review, we collected available literature on bortezomib use in AIHA and in other immune-mediated hematologic and non-hematologic diseases. Overall, most experiences highlight bortezomib efficacy even in multi-relapsed/refractory patients and suggest to consider its use in AIHA after rituximab failure.

Bortezomib in anti-N-Methyl-d-Aspartate-Receptor (NMDA-R) encephalitis: A systematic review

N-methyl-d-aspartate receptor (NMDAR) encephalitis is a potentially treatable condition, although a small proportion of patients remains refractory to immunotherapy. Bortezomib is a proteasome inhibitor that has a promising role in autoimmune conditions. We performed an independent PubMed search employing "Anti-N-Methyl‑D-Aspartate encephalitis AND bortezomib", including papers published between January 1st, 2007 to April 15th, 2021. Fourteen articles were included, with 29 patients. 16 patients (55,2%) had a favorable outcome after bortezomib and 11 (37,9%) patients developed side effects. Quality of studies was overall poor and future trials should aim to include more homogeneous and larger cohorts.

Management of autoimmune encephalitis

PURPOSE OF REVIEW

Autoimmune encephalitides are established diagnoses in contemporary neurology. Their management poses a regular challenge for almost all neurologists. One may ask if the concept of 1st line and 2nd line treatment is still up to date, which new data on the antibody-defined encephalitis types exist, and how to organize long-term management.

RECENT FINDINGS

The 1st line/2nd line concept of initial immunological intervention is accepted worldwide. A randomized controlled trial confirmed that one 1st line compound (intravenous immunoglobulins) is superior to a placebo in patients with antibodies against leucine-rich glioma inactivated protein 1. Rituximab, a 2nd line compound, is increasingly and apparently successfully used in treating different types of autoimmune encephalitis. It may find its place even earlier in the treatment cascade. Long-term management needs to be improved and is under development.

SUMMARY

There have been no groundbreaking new developments in the field. The published experience confirms existing suggestions. Aspects of long-term management including rehabilitation measures and counseling about driving eligibility require further research.