Limbic encephalitis with antibodies to N-methyl-d-aspartate (NMDA)-type glutamate receptor after allogeneic transplantation

Encephalitis with Antibodies Against Glial Fibrillary Acidic Protein (GFAP) After Allogeneic Hematopoietic Stem Cell Transplantation: A Rare Case Report and Literature Review

In this report, the patient was a 57-year-old woman who had been diagnosed with aplastic anemia for 3 years. This patient underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). Twenty-four months after allo-HSCT, the patient experienced cognitive dysfunction, memory loss, and involuntary movements. Various central nervous system (CNS) complications may occur after allo-HSCT, which can lead to severe clinical problems. Diagnosis is often difficult because of the absence of distinctive clinical symptoms. In addition, different neurological disorders may show similar symptoms. Although antibodies in the CSF or serum have become well recognized in several CNS disorders, cases of autoimmune CNS disorders after allo-HSCT have rarely been reported. Here, we report the case of a patient who developed encephalitis associated with antibodies against glial fibrillary acidic protein (GFAP) after allo-HSCT. To the best of our knowledge, this is the first report of the involvement of antibodies against GFAP in post-transplantation encephalitis. Of course, all processes met the ethical and patient consents were obtained.

Case report: Autoimmune encephalomyelitis following cytomegalovirus infection after allogeneic hematopoietic stem cell transplantation

Introduction

Cytomegalovirus (CMV) can cause various end-organ diseases in immunocompromised hosts, including allogeneic hematopoietic cell transplant (allo-HSCT) recipients. Interestingly, CMV viremia has been associated with various complications and poor prognosis in allo-HSCT recipients. Complications involving the central nervous system (CNS) occur in 9-14% of patients following allo-HSCT. However, autoimmune encephalitis (AE) secondary to CMV infection after allo-HSCT has rarely been reported. Here we report a case of possible AE following CMV viremia after allo-HSCT, which was successfully treated with high-dose pulsed methylprednisolone and intravenous immunoglobulins (IVIg).

Case description

A 53-year-old female underwent allo-HSCT for T-lymphoblastic lymphoma/leukemia. The patient developed CMV viremia on day 36 after transplantation, and serum CMV-DNA remained positive after initiating ganciclovir antiviral therapy, turning negative one month later. Four months later, she started experiencing memory impairment, weakness in the left limbs, cognitive dysfunction, and hallucinations. A magnetic resonance imaging brain scan showed scattered ischemic lesions under the bilateral frontal cortex. Viral detection in cerebral spinal fluid (CSF) by next-generation gene sequencing technology showed no obvious abnormality. Antibodies specific to AE and paraneoplastic diseases in serum and CSF were absent. The oligoclonal bands in the CSF were detected using isoelectric focusing and immunofixation, and the results were negative. However, after extensive investigation regarding infections, autoimmune disorders, and recurrence of the malignancy, possible AE could not be excluded. The patient was treated with high-dose steroids combined with IVIg therapy; the patient's symptoms were significantly improved.

Conclusion

The mechanisms of AE after allo-HSCT and the relationship with CMV infection should be further studied. Therefore, reporting this and similar cases will improve our awareness and understanding of the underlying disease mechanisms.

Hematologic malignancies and hematopoietic stem cell transplantation

Paraneoplastic neurologic syndromes are rarely associated with hematologic malignancies. In their rarity, lymphomas are the diseases with more frequent paraneoplastic neurologic syndrome. High-risk antibodies are absent in most lymphoma-associated paraneoplastic neurologic syndromes, with the exception of antibodies to Tr/DNER in paraneoplastic cerebellar degeneration, mGluR5 in limbic encephalitis, and mGluR1 in some cerebellar ataxias. Peripheral nervous system paraneoplastic neurologic syndromes are rare and heterogeneous, with a prevalence of demyelinating polyradiculoneuropathy in non-Hodgkin lymphoma. Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (POEMS) is a rare, paraneoplastic syndrome due to an underlying plasma cell disorder. The diagnosis is based on defined criteria, and vascular endothelial growth factor (VEGF), not an antibody, is considered a reliable diagnostic marker that also mirrors therapy response. As with the paraneoplastic neurologic syndromes in solid tumors, therapies rely on cancer treatment associated with immunomodulatory treatment with better response in PNS with antibodies to surface antigens. The best outcome is generally present in Ophelia syndrome/limbic encephalitis with anti-mGluR5 antibodies, with frequent complete recovery. Besides patients with isolated osteosclerotic lesions (where radiotherapy is indicated), hematopoietic stem-cell transplantation is the therapy of choice in patients with POEMS syndrome. In the paraneoplastic neurologic syndromes secondary to immune checkpoint inhibitors, discontinuation of the drug together with immunomodulatory treatment is recommended.

Stem Cell Therapy in Neuroimmunological Diseases and Its Potential Neuroimmunological Complications

Background: Since the 1990s, transplantations of hematopoietic and mesenchymal stem cells (HSCT and MSCT) and dendritic cell (DCT) have been investigated for the treatment of neurological autoimmune disorders (NADs). With the growing number of transplanted patients, awareness of neuroimmunolgical complications has increased. Therefore, an overview of SCT for the most common NADs and reports of secondary immunity after SCT is provided. Methods: For this narrative review, a literature search of the PubMed database was performed. A total of 86 articles reporting on different SCTs in NADs and 61 articles dealing with immune-mediated neurological complications after SCT were included. For multiple sclerosis (MS), only registered trials and phase I/II or II studies were considered, whereas all available articles on other disorders were included. The different transplantation procedures and efficacy and safety data are presented. Results: In MS patients, beneficial effects of HSCT, MSCT, and DCT with a decrease in disability and stabilization of disease activity have been reported. These effects were also shown in other NADs mainly in case reports. In seven of 132 reported patients with immune-mediated neurological complications, the outcome was fatal. Conclusions: Phase III trials are ongoing for MS, but the role of SCT in other NADs is currently limited to refractory patients due to occasional serious complications.

Diagnostic approach and treatment regimens in adult patients suffering from antibody-mediated or paraneoplastic encephalitis

Identification of patients with antibody-mediated encephalitis poses a diagnostic challenge and any delay in that respect will increase the interval until initiation of immunotherapy and may negatively affect the patient´s clinical outcome. Within this review we focus on therapeutic strategies in antibody-mediated encephalitis and propose how to proceed with patients, who are suspected to have encephalitis of unknown origin. We further briefly outline differences in treatment of paraneoplastic and antibody-mediated encephalitis according to its pathomechanisms.

Neuropathological Variability within a Spectrum of NMDAR-Encephalitis

OBJECTIVE

To describe the neuropathological features of N-methyl-D-aspartate receptor (NMDAR)-encephalitis in an archival autopsy cohort.

METHODS

We examined four autopsies from patients with NMDAR-encephalitis; two patients were untreated, three had comorbidities: small cell lung cancer, brain post-transplant lymphoproliferative disease (PTLD), and overlapping demyelination.

RESULTS

The two untreated patients had inflammatory infiltrates predominantly composed of perivascular and parenchymal CD3+ /CD8- T cells and CD79a+ B cells/plasma cells in basal ganglia, amygdala, and hippocampus with surrounding white matter. The hippocampi showed a significant decrease of NMDAR-immunoreactivity that correlated with disease severity. The patient with NMDAR-encephalitis and immunosuppression for kidney transplantation developed a brain monomorphic PTLD. Inflammatory changes were compatible with NMDAR-encephalitis. Additionally, plasma cells accumulated in the vicinity of the necrotic tumor along with macrophages and activated microglia that strongly expressed pro-inflammatory activation markers HLA-DR, CD68, and IL18. The fourth patient developed demyelinating lesions in the setting of a relapse 4 years after NMDAR-encephalitis. These lesions exhibited the hallmarks of classic multiple sclerosis with radially expanding lesions and remyelinated shadow plaques without complement or immunoglobulin deposition, compatible with a pattern I demyelination.

INTERPRETATION

The topographic distribution of inflammation in patients with NMDAR-encephalitis reflects the clinical symptoms of movement disorders, abnormal behavior, and memory dysfunction with inflammation dominantly observed in basal ganglia, amygdala, and hippocampus, and loss of NMDAR-immunoreactivity correlates with disease severity. Co-occurring pathologies influence the spatial distribution, composition, and intensity of inflammation, which may modify patients' clinical presentation and outcome. ANN NEUROL 2021;90:725-737.

Risk Factor and Long-Term Outcome Analyses for Acute Limbic Encephalitis and Calcineurin Inhibitor-Induced Encephalopathy in Adults following Allogeneic Hematopoietic Cell Transplantation

Post-transplantation acute limbic encephalitis (PALE) is a rare, severe inflammatory disorder in the bilateral limbic system, including the hippocampus. To date, only a few studies have reported details, including risk factors for PALE; however, further clinical evidence of PALE, especially in cerebrospinal fluid human herpesvirus 6-negative cases, is warranted. In addition, data are sparse regarding the risk factors for calcineurin inhibitor (CNI)-induced encephalopathy (CNIE) following allogeneic hematopoietic cell transplantation (allo-HCT) in adults. Therefore, we examined the risk factors for and clinical details of PALE and CNIE. We retrospectively analyzed consecutive patients who underwent allo-HCT between January 2005 and November 2017. A total of 485 patients age 46 years (median) were eligible. In total, 14 PALE cases and 11 CNIE cases were identified. Multivariable analyses identified older age, use of an HLA-mismatched unrelated donor (URD), graft-versus-host disease (GVHD) prophylaxis with CNI and mycophenolate mofetil, and grade II-IV acute GVHD as significantly associated with an increased risk of PALE. In 13 patients who received high-dose methylprednisolone (mPSL) therapy, 6 (46%) responded to mPSL therapy, and 3 (23%) achieved complete remission at day 90 after mPSL administration. Furthermore, myelodysplastic syndrome (MDS), HLA-mismatched URD, and grade II-IV acute GVHD were significantly associated with an increased risk of CNIE. The 5-year nonrelapse mortality rate was 50% in PALE and 63% in CNIE, suggesting a very poor prognosis. In conclusion, this study provides evidence that HLA-mismatched URD and acute GVHD may independently contribute to the development of PALE, possibly in part through HLA-mismatch-derived alloimmune responses. Other than acute GVHD, we have identified MDS and HLA-mismatched URD as novel predictors of CNIE after allo-HCT.