Brief research report: in-depth immunophenotyping reveals stability of CD19 CAR T-cells over time.

Variability or stability might have an impact on treatment success and toxicity of CD19 CAR T-cells. We conducted a prospective observational study of 12 patients treated with Tisagenlecleucel for CD19+ B-cell malignancies. Using a 31-color spectral flow cytometry panel, we analyzed differentiation stages and exhaustion markers of CAR T-cell subsets prior to CAR T-cell infusion and longitudinally during 6 months of follow-up. The majority of activation markers on CAR T-cells showed stable expression patterns over time and were not associated with response to therapy or toxicity. Unsupervised cluster analysis revealed an immune signature of CAR T-cell products associated with the development of immune cell-associated neurotoxicity syndrome. Warranting validation in an independent patient cohort, in-depth phenotyping of CAR T-cell products as well as longitudinal monitoring post cell transfer might become a valuable tool to increase efficacy and safety of CAR T-cell therapy.

The relevance of NMDA receptor antibody-specific index for diagnosis and prognosis in patients with anti-NMDA receptor encephalitis.

The clinical implications of the presence of anti-N-methyl-D-aspartate receptor (NMDAR)-specific intrathecal immunoglobulin G synthesis and whether it determines the diagnosis of anti-NMDAR encephalitis have not been thoroughly investigated yet. Thus, the aim of this study was to investigate whether the detection of intrathecal anti-NMDAR-specific IgG synthesis contributes to the diagnostic confirmation of anti-NMDAR encephalitis, to disease severity, and to prognosis in patients with positive serum anti-NMDAR-IgG. In this study, patients with detectable anti-NMDAR IgG in serum and/or cerebrospinal fluid (CSF) were included and separated into two groups that either met the 2016 criteria by Graus et al. of definite anti-NMDAR encephalitis (n = 27) or did not (n = 15). In a total, of 80 paired CSF/serum samples, antibody titers were titrated manually and end-point titer levels were carefully determined in a blinded manner to the subgroup attribution. The disease course was assessed via the modified Rankin Scale (mRS) and prognosis was estimated by the anti-NMDAR Encephalitis One-Year Functional Status (NEOS) score. With respect to whether the diagnostic Graus criteria for definite anti-NMDAR encephalitis were fulfilled, a significantly unequal distribution of intrathecal anti-NMDAR antibody-specific synthesis could be shown with a high negative predictive value in case of a negative anti-NMDAR antibody-specific index (NMDAR AI, p = .008. OR = 23.9, sensitivity = 1.0, specificity = 0.4, negative predictive value = 1). A weak correlation was found between the CSF antibody titer and mRS value at the time of sample collection (rs = .37, p = .008, 95% CI [.09, .59]). During the disease course a higher delta-mRS value formed of the mRS at initial presentation minus that at the last recorded presentation correlated with a higher NMDAR AI at first lumbar puncture (rs = - .56, p = .017, 95% CI [- .83, - .11]). No association with the prognostic NEOS score was found. In conclusion, a negative antibody-specific index for anti-NMDAR IgG antibodies has a highly negative predictive value for the diagnosis of anti-NMDAR encephalitis. Yet, a positive NMDAR AI alone does not allow the diagnosis of anti-NMDAR encephalitis.

Adoptive Allogeneic T-Cell Therapy Improves the Clinical Outcome of JC Virus Granule Cell Neuronopathy: A Case Report.

OBJECTIVES: JC virus granule cell neuronopathy is a potentially fatal otherwise highly disabling disease without an approved therapeutic option. This case report presents the positive record to T-cell therapy in JC virus granule cell neuronopathy. METHODS: The patient represented with subacute cerebellar symptoms. Diagnosis of JC virus granule cell neuronopathy was made because of infratentorially accentuated brain volume atrophy shown by brain MRI and the detection of JC virus DNA in the CSF. RESULTS: Six doses of virus-specific T cells were administered. Within 12 months after therapy initiation, the patient showed clear clinical benefit with improvement of symptoms, and JC viral DNA load significantly declined. DISCUSSION: We present the case report of a positive response to T-cell therapy in JC virus granule cell neuronopathy, leading to an improvement of symptoms.

Monocyte chemoattractant protein 1 as a potential biomarker for immune checkpoint inhibitor-associated neurotoxicity.

BACKGROUND: Oncological patients can benefit substantially from treatment with immune checkpoint inhibitors (ICI). However, there is a growing awareness of immune-related adverse events (irAE). Especially ICI-mediated neurological adverse events (nAE(+)), are tough to diagnose and biomarkers to identify patients at risk are missing. METHODS: A prospective register with prespecified examinations was established for ICI treated patients in December 2019. At the time of data cut-off, 110 patients were enrolled and completed the clinical protocol. Herein, cytokines and serum neurofilament light chain (sNFL) from 21 patients were analyzed. RESULTS: nAE of any grade were observed in 31% of the patients (n = 34/110). In nAE(+) patients a significant increase in sNFL concentrations over time was observed. Patients with higher-grade nAE had significantly elevated serum-concentrations of monocyte chemoattractant protein 1 (MCP-1) and brain-derived neurotrophic factor (BDNF) at baseline compared to individuals without any nAE (p < 0.01 and p < 0.05). CONCLUSION: Here, we identified nAE to occur more frequently than previously reported. Increase of sNFL during nAE confirms the clinical diagnosis of neurotoxicity and might be a suitable marker for neuronal damage associated with ICI therapy. Furthermore, MCP-1 and BDNF are potentially the first clinical-class nAE predictors for patients under ICI therapy.

IgG4-related hypertrophic pachymeningitis with tumor-like intracranial and intracerebral lesions.

OBJECTIVE: IgG4-related hypertrophic pachymeningitis is a rare fibroinflammatory disorder that may cause localized or diffused thickening of the dura mater. Misinterpretations of the clinical and imaging findings are common. Clinical manifestations depend on the location of the inflammatory lesion and on compression of neural structures leading to functional deficits. A dural biopsy is commonly needed for a definitive diagnosis. Immunomodulatory therapy is considered the therapy of choice. METHODS: Four patients with IgG4-related hypertrophic pachymeningitis were identified over a 5-year period. Patient-related characteristics including age, preoperative workup, signs and symptoms of patients, and diagnostic procedures were evaluated. Furthermore, the surgical treatment and 5-year follow-up outcomes were analyzed. RESULTS: There were two adults and two adolescents (mean age 32 years; range 15 to 67 years). Two patients were male, and two were female. No history of disease was known in any of the patients. Clinical symptoms were epilepsy (n = 2), ataxia and nausea (n = 1), and facial nerve palsy (n = 1). MR imaging studies showed contrast enhancing lesions in the temporal region in two patients, and in the cerebellar region in the other two patients. Subtotal resection was performed in two instances and a biopsy via a suboccipital retrosigmoid approach was obtained in the other two patients. Histochemical and immunohistochemical investigations revealed an IgG 4 disease in all of these patients. Immunomodulatorry therapy led to clinical stability during follow-up of 5 years in all four cases. CONCLUSION: The diagnosis of IgG4-related hypertrophic pachymeningitis is challenging, but is of great relevance as treatment differs significantly from other forms of pachymeningitis and a specific therapeutic approach may avoid long-term neurological complications. Our series contributes to a better clinical characterization of this rare disease.

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.

Innovative therapeutic concepts of progressive multifocal leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is an opportunistic viral disease of the brain-caused by human polyomavirus 2. It affects patients whose immune system is compromised by a corresponding underlying disease or by drugs. Patients with an underlying lymphoproliferative disease have the worst prognosis with a mortality rate of up to 90%. Several therapeutic strategies have been proposed but failed to show any benefit so far. Therefore, the primary therapeutic strategy aims to reconstitute the impaired immune system to generate an effective endogenous antiviral response. Recently, anti-PD-1 antibodies and application of allogeneic virus-specific T cells demonstrated promising effects on the outcome in individual PML patients. This article aims to provide a detailed overview of the literature with a focus on these two treatment approaches.

Neurological management and work-up of neurotoxicity associated with CAR T cell therapy.

INTRODUCTION: Treatment with CD19 chimeric antigen receptor (CAR) T cells is an innovative therapeutic approach for patients with relapsed/refractory diffuse large B cell lymphoma (r/rDLBCL) and B-lineage acute lymphoblastic leukemia (r/rALL). However, convincing therapeutic response rates can be accompanied by cytokine release syndrome (CRS) and severe neurotoxicity termed immune effector cell-associated neurotoxicity syndrome (ICANS). METHODS: Single center, prospective observational study of fifteen consecutive r/r DLBCL patients treated with Tisagenlecleucel within 1 year at Hannover Medical School. Extensive neurological work-up prior to CAR T cell infusion included clinical examination, cognitive testing (Montreal-Cognitive-Assessment), brain MRI, electroencephalogram, electroneurography, and analysis of cerebrospinal fluid. After CAR T cell infusion, patients were neurologically examined for 10 consecutive days. Afterwards, all patients were assessed at least once a week. RESULTS: ICANS occurred in 4/15 patients (27%) within 6 days (4-6 days) after CAR T cell infusion. Patients with ICANS grade 2 (n = 3) exhibited similar neurological symptoms including apraxia, expressive aphasia, disorientation, and hallucinations, while brain MRI was inconspicuous in either case. Treatment with dexamethasone rapidly resolved the clinical symptoms in all three patients. Regarding baseline parameters prior to CAR T cell treatment, patients with and without ICANS did not differ. CONCLUSIONS: In our cohort, ICANS occurred in only every fourth patient and rather low grade neurotoxicity was found during daily examination. Our results demonstrate that a structured neurological baseline examination and close monitoring are helpful to detect CAR T cell related neurotoxicity already at an early stage and to potentially prevent higher grade neurotoxicity.

Differentiation of viral and autoimmune central nervous system inflammation by kynurenine pathway.

OBJECTIVE: To determine whether the metabolites of Kynurenine pathway (KP) could serve as biomarkers for distinguishing between viral CNS infections and autoimmune neuroinflammatory diseases, especially anti-N-methyl-D-aspartate receptor encephalitis (NMDARE) and herpes virus encephalitis (HSE). METHODS: This study enrolled CSF samples from 76 patients with viral CNS infections, autoimmune neuroinflammatory, and non-inflammatory neurological diseases. We measured cerebrospinal fluid (CSF) concentrations of tryptophan (Trp) and kynurenine (Kyn) by ELISA. RESULTS: Kyn concentrations and Kyn/Trp ratios were highly increased (p < 0.001, viral vs. autoimmune) in viral CNS infections, whereas patients with autoimmune neuroinflammatory and non-inflammatory diseases exhibited low concentrations. Furthermore, Kyn concentrations and Kyn/Trp ratio turned out to be excellent biomarkers to distinguish between herpes simplex encephalitis (HSE) and NMDARE (AUC 0.920 and AUC 0.906), whereas Trp concentrations were similar in all three groups. INTERPRETATION: The results suggest that elevated CSF Kyn concentrations and Kyn/Trp ratio may serve as biomarkers for distinguishing viral CNS infections from autoimmune neuroinflammatory diseases. In particular, the distinction between HSE and NMDARE is of great clinical relevance. Further studies are warranted to investigate the potential of CSF Kyn levels and Kyn/Trp ratio as routine parameters in patients with CNS diseases.

Intrathecal Antibody Production Against Epstein-Barr, Herpes Simplex, and Other Neurotropic Viruses in Autoimmune Encephalitis.

BACKGROUND AND OBJECTIVES: Neurotropic viruses are suspected to play a role in the pathogenesis of autoimmune diseases of the CNS such as the association between the Epstein-Barr virus (EBV) and multiple sclerosis (MS). A group of autoimmune encephalitis (AE) is linked to antibodies against neuronal cell surface proteins. Because CNS infection with the herpes simplex virus can trigger anti-NMDA receptor (NMDAR) encephalitis, a similar mechanism for EBV and other neurotropic viruses could be postulated. To investigate for previous viral infections of the CNS, intrathecally produced virus-specific antibody synthesis was determined in patients with AE. METHODS: Antibody-specific indices (AIs) against EBV and measles, rubella, varicella zoster, herpes simplex virus, and cytomegalovirus were determined in 27 patients having AE (anti-NMDAR encephalitis, n = 21, and LGI1 encephalitis, n = 6) and in 2 control groups comprising of 30 patients with MS and 21 patients with noninflammatory CNS diseases (NIND), which were sex and age matched. RESULTS: An intrathecal synthesis of antibodies against EBV was found in 5/27 (19%) patients with AE and 2/30 (7%) of the patients with MS. All these patients had also at least 1 additional elevated virus-specific AI. In contrast, in none of the patients with NIND, an elevated virus-specific AI was detected. DISCUSSION: Intrathecally produced antibodies against EBV can be found in patients with AE and MS but only together with antibodies against different neurotropic viruses. Evidence of these antibodies is the result of a polyspecific immune response similar yet distinct from MS response rather than an elapsed infection of the CNS.

PD-1-inhibitor pembrolizumab for treatment of progressive multifocal leukoencephalopathy.

The reactivation of human JC polyoma virus (JCPyV) results in lytic infection of oligodendrocytes and neuronal cells. The corresponding clinical picture is called progressive multifocal leukoencephalopathy (PML) and results mostly from a disease-related or drug-induced immunosuppression. The opportunistic brain infection leads to a progressive demyelination of multiple areas of the central nervous system. Patients can present with various neurological deficits ranging from slight motoric symptoms to marked aphasia or reduced vigilance. Currently, there is no effective causal therapy for PML. Survival depends on the ability to achieve timely immune reconstitution. If the immune system cannot be restored, PML progresses rapidly and often ends fatally within months. Recently, some evidence for positive response has been reported in patients treated with immune checkpoint inhibitor therapy. Here, we provide a case series of three PML patients with underlying hematological malignancies who were treated with anti-PD-1-antibody pembrolizumab at Hannover Medical School. All patients received an extensive diagnostic follow-up including cerebrospinal fluid analysis, brain imaging, and lymphocyte-phenotyping via flow cytometry. Our patients had very different outcomes, with the only patient showing a specific anti-JCPyV immune response in the sense of an increased JCPyV antibody index clearly benefiting most from the treatment. Our results partly support the hypothesis that anti-PD-1 therapy may represent a promising treatment option for patients with PML. However, there is a current lack of pre-therapeutic stratification regarding the therapeutic response rates. Before larger studies can be initiated to further evaluate the efficacy of anti-PD-1 antibodies in PML, it is imperative to develop a reliable strategy for selecting suitable patients.

Allogeneic BK Virus-Specific T-Cell Treatment in 2 Patients With Progressive Multifocal Leukoencephalopathy.

OBJECTIVE: Progressive multifocal leukoencephalopathy (PML) is a devastating demyelinating opportunistic infection of the brain caused by the ubiquitously distributed JC polyomavirus. There are no established treatment options to stop or slow down disease progression. In 2018, a case series of 3 patients suggested the efficacy of allogeneic BK virus-specific T-cell (BKV-CTL) transplantation. METHODS: Two patients, a bilaterally lung transplanted patient on continuous immunosuppressive medication since 17 years and a patient with dermatomyositis treated with glucocorticosteroids, developed definite PML according to AAN diagnostic criteria. We transplanted both patients with allogeneic BKV-CTL from partially human leukocyte antigen (HLA) compatible donors. Donor T cells had directly been produced from leukapheresis by the CliniMACS IFN-γ cytokine capture system. In contrast to the previous series, we identified suitable donors by HLA typing in a preexamined registry and administered 1 log level less cells. RESULTS: Both patients' symptoms improved significantly within weeks. During the follow-up, a decrease in viral load in the CSF and a regression of the brain MRI changes occurred. The transfer seemed to induce endogenous BK and JC virus-specific T cells in the host. CONCLUSIONS: We demonstrate that this optimized allogeneic BKV-CTL treatment paradigm represents a promising, innovative therapeutic option for PML and should be investigated in larger, controlled clinical trials. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that for patients with PML, allogeneic transplant of BKV-CTL improved symptoms, reduced MRI changes, and decreased viral load.

Severe allo-immune antibody-associated peripheral and central nervous system diseases after allogeneic hematopoietic stem cell transplantation.

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a curative treatment for hematologic malignancies. Acute and chronic graft-versus-host disease (GvHD) are the major immune-mediated complications after alloHSCT. However, there is controversy whether neurologic complications after alloHSCT might represent manifestations of GvHD. We report three patients who acquired distinct, severe immune-mediated peripheral or central nervous system diseases after alloHSCT without other, concomitant GvHD manifestations. One patient had been diagnosed with B-cell chronic lymphocytic leukemia and two patients with high risk myelodysplastic syndrome. Patient #1 presented as LGI1- and GAD-IgG positive immune-mediated encephalitis, patient #2 was diagnosed with MOG-IgG positive encephalomyelitis, and patient #3 had chronic inflammatory polyneuropathy associated with SSA(Ro)-IgG positive Sjögren's syndrome. 100% donor chimerism was detectable in the peripheral blood in all three. The specific antibodies were undetectable in donors' and patients' blood before alloHSCT suggesting that the antibodies had arisen from the transplanted donor immune system. Early intensive immunotherapy led to improvement of clinical symptoms and stability of the neurological disease, however, at the cost of losing the graft-versus-malignancy effect in one patient. In conclusion, we provide evidence of isolated, severe allo-immune diseases of the peripheral and central nervous system as complications of alloHSCT ("neuro-GvHD"). Interdisciplinary surveillance and thorough diagnostic work-up are needed for early diagnosis and treatment of neuro-immunologic complications after alloHSCT to improve the otherwise poor outcome.

18F-FDG PET/CT of off-target lymphoid organs in CD19-targeting chimeric antigen receptor T-cell therapy for relapsed or refractory diffuse large B-cell lymphoma.

OBJECTIVE: The interplay between systemic inflammation, activity of lymphoid organs and lymphoma activity in CD19-targeting chimeric antigen receptor (CAR)-T-cell immunotherapy, and its significance for response and toxicity, is not well defined. METHODS: Using serial 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT), metabolic parameters of lymphoma and lymphoid organs were analyzed in ten patients receiving Tisagenlecleucel (an autologous CD19 CAR-T cell product) for relapsed or refractory diffuse large B-cell lymphoma. The prevalence and severity of toxicity (e.g., neurotoxicity) were noted. RESULTS: Achieving remission required early metabolic response (P = 0.0476). Early suppression of metabolic activity of lymphoid organs (spleen, P = 0.0368; lymph nodes, P = 0.0470) was associated with poor outcome. Lymphoma metabolic activity was significantly higher in patients with neurotoxicity (P = 0.0489). CONCLUSIONS: Early metabolic changes in lymphoma lesions and off-target lymphoid organs parallel medium-term response to CAR-T-cell therapy. PET can identify patients at risk for severe toxicity.

Diagnosis and Differential Diagnosis of Neurological Adverse Events during Immune Checkpoint Inhibitor Therapy.

Therapy with immune checkpoint inhibitors (ICIs) has improved overall survival and cancer-related morbidity of cancer treatment even in cancer entities with poor prognosis. Since the approval of the first ICI, ipilimumab, for treatment of advanced melanoma by the Food and Drug Administration (FDA) in 2011, the spectrum of indications and approved ICIs has grown, rapidly. Up to now, seven different ICIs for more than 20 indications are available. However, their mechanisms of action can lead to immune-related adverse events (irAEs). In particular, neurological irAEs are clinically relevant. Although they are rare, an early and accurate diagnosis is challenging and neurological disease course and sequelae are potentially fatal. Between 08/2017 and 03/2020, 31 patients received ICI treatment at Hannover Medical School and presented with neurological adverse events (N-irAEs). Treated malignancies were metastatic melanoma, bronchial carcinoma, and urothelial cell carcinoma. All patients received comprehensive neurological diagnostics including clinical examination and magnetic resonance imaging (MRI). Cerebrospinal fluid (CSF) analysis was obtained in 21 patients and electroneurography was performed in 22 patients. Although N-irAEs were suspected in all 31 patients, 11 patients had other conditions leading to neurological symptoms including tumor metastases in seven patients and hemorrhagic or ischemic stroke in four patients. In the following, these patients are referred to as the differential diagnosis (DD) group. Patients with N-irAEs suffered from immune mediated neuropathy (9/20), myositis and/or myasthenic syndrome (6/20), or encephalitis/cerebellitis (5/20). Except for cell count, CSF results did not differ between the N-irAEs and the DD group. Symptoms related to N-irAEs are rather unspecific potentially mimicking other tumor-related symptoms such as metastases. Patients with malignancy are predominantly not treated by neurologists. Because of the complexity of neurological symptoms, detailed neurological investigations in specialized institutions are necessary in patients with new neurological symptoms and need to be critically discussed with treating oncologists.

Targeted metabolomic profiling of cerebrospinal fluid from patients with progressive multifocal leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML), caused by JC polyomavirus, is a demyelinating disease of the central nervous system that primarily affects oligodendrocytes. It can cause significant morbidity and mortality. An early diagnosis is of high relevance as timely immune reconstitution is essential. However, diagnosis can be challenging if virus detection via cerebrospinal fluid (CSF) PCR remains negative. Hence, identifying CSF biomarkers for this disease is of crucial importance. We applied a targeted metabolomic screen to CSF from 23 PML patients and eight normal pressure hydrocephalus (NPH) patients as controls. Out of 188 potentially detectable metabolites, 48 (13 amino acids, 4 biogenic amines, 1 acylcarnitine, 21 phosphatidylcholines, 8 sphingolipids, and the sum of hexoses) passed the quality screen and were included in the analyses. Even though there was a tendency towards lower concentrations in PML (mostly of phosphatidylcholines and sphingomyelins), none of the differences between PML and controls in individual metabolite concentrations reached statistical significance (lowest p = 0.104) and there were no potential diagnostic biomarkers (highest area under the ROC curve 0.68). Thus, CSF metabolite changes in PML are likely subtle and possibly larger group sizes and broader metabolite screens are needed to identify potential CSF metabolite biomarkers for PML.

Cerebrospinal fluid analysis in 108 patients with progressive multifocal leukoencephalopathy.

BACKGROUND: Progressive multifocal leukoencephalopathy (PML) is caused by an opportunistic infection with JC polyoma virus (JCPyV) and mainly affects immunocompromised patients. It leads to pronounced demyelination of the central nervous system (CNS) resulting in severe disability or even death. Detection of JCPyV DNA in the cerebrospinal fluid (CSF) is usually accepted as proof for the diagnosis of PML. Routine CSF parameters, like CSF cell count, protein concentration, Qalbumin, or intrathecal immunoglobulin synthesis are mostly considered normal. However, this has not been investigated systematically. METHODS: We analyzed routine CSF parameters in a cohort of 108 PML patients that were treated at four different neurological centers in Germany. The patients exhibited different underlying conditions with natalizumab-treated multiple sclerosis (n = 54) and human immunodeficiency virus (HIV)-infection (n = 25) being the most frequent. The data were collected at the respective centers in accordance with local requirements and then jointly analyzed. The total PML cohort was compared with a control group of patients with normal pressure hydrocephalus (NPH) and idiopathic intracranial hypertension (IIH). Multiple sclerosis and HIV patients were additionally compared with their own non-PML control groups. RESULTS: The PML group showed an elevated cell count (p < 0.001) compared to the control group, however, this effect was mainly driven by HIV-PML patients. This subgroup also demonstrated a significantly higher proportion of patients with a disturbed blood-CSF-barrier function. CONCLUSIONS: This comprehensive, retrospective study on CSF diagnostic analysis in PML patients provides insight into the CSF of those patients. It demonstrates that CSF composition in PML patients may be specific for the underlying condition that predisposes for the development of PML and thus data have to be interpreted in this context.

Extracorporeal cytokine removal in severe CAR-T cell associated cytokine release syndrome.

PURPOSE: Life-threatening complications of CD-19 Chimeric antigen receptor - T (CAR-T) cells such as the cytokine release syndrome (CRS)) have been reported. Treatment is limited to IL-6 blockade and steroids although global removal of elevated soluble inflammatory factors might be more effective. METHODS: Clinical course of a CRS patient treated with extracorporeal cytokine adsorption (Cytosorb®). A panel of 48 cytokines, chemokines and endothelial markers has been analyzed longitudinally. Ex vivo stimulation of endothelial cells to visualize (immunocytochemistry) and quantify (ECIS, TER) endothelial barrier effects. RESULTS: Following CAR-T cell application a 65 years old male developed grade 4 CRS with refractory shock (3 vasopressors) and severe capillary leakage (+37 L/24 h resuscitation). Treatment included IL-6 blockade, methylprednisolone and additionally Cytosorb hemoperfusion. While multiple soluble inflammatory factors were elevated and most of them decreased by more than 50% following Cytosorb, markers of endothelial injury increased steadily (e.g. Angpt-2/Angpt-1) leading to profound endothelial activation and leakage in ex vivo assays. CONCLUSION: This is the first reported use of cytokine adsorption for CRS showing efficacy in absorption of various cytokines but not endothelial growth factors. A randomized controlled trial to evaluate additional Cytosorb treatment in CRS is currently recruiting at our institution (NCT04048434).

Neurological Immune Related Adverse Events Associated with Nivolumab, Ipilimumab, and Pembrolizumab Therapy-Review of the Literature and Future Outlook.

Immune checkpoint inhibitor (ICI) therapy has revolutionized the management of various cancers with previously poor prognosis. Despite its great efficacy, the therapy is associated with a wide spectrum of immune-related adverse events (irAE) including neurological symptoms which can affect all parts of the central and peripheral nervous system. Even though these events are rare, they are of high relevance as the rate of residual symptoms or even fatal outcomes is remarkable. To provide a detailed overview of neurological adverse events associated with immune checkpoint-inhibitor therapy we conducted a literature search. While focusing on ipilimumab, nivolumab, and pembrolizumab therapy, all available case reports as well as larger case series and clinical trials have been considered. Eighty-two case reports about checkpoint-inhibitor therapy induced symptoms of the peripheral nervous system have been published, while only 43 case reports addressed central nervous system abnormalities. The frequency of immune checkpoint-inhibitor therapy inducing neurological adverse events is about 1% in larger studies. Especially neuromuscular adverse events exhibit distinct clinical and diagnostic characteristics. Additionally, several affected patients presented with overlap-syndromes, which means that symptoms and diagnostic findings indicating myositis, myasthenia gravis, and neuropathy were present in one individual patient at the same time. Thus, neurological and particularly neuromuscular adverse events of immune checkpoint-inhibitor therapy may constitute a new disease entity.