Central nervous system immune-related disorders after SARS-CoV-2 vaccination: a multicenter study

Background

COVID-19 vaccines have been approved due to their excellent safety and efficacy data and their use has also permitted to reduce neurological complications of SARS-CoV-2. However, clinical trials were underpowered to detect rare adverse events. Herein, the aim was to characterize the clinical spectrum and immunological features of central nervous system (CNS) immune-related events following SARS-CoV-2 vaccination.

Methods

Multicenter, retrospective, cohort study (December 1, 2020-April 30, 2022). Inclusion criteria were (1) de novo CNS disorders developing after SARS-CoV-2 vaccination (probable causal relationship as per 2021 Butler criteria) (2); evidence for an immune-mediated etiology, as per (i) 2016 Graus criteria for autoimmune encephalitis (AE); (ii) 2015 Wingerchuk criteria for neuromyelitis optica spectrum disorders; (iii) criteria for myelitis.

Results

Nineteen patients were included from 7 tertiary referral hospitals across Italy and France (one of them being a national referral center for AE), over almost 1 year and half of vaccination campaign. Vaccines administered were mRNA-based (63%) and adenovirus-vectored (37%). The median time between vaccination and symptoms onset was 14 days (range: 2-41 days). CSF was inflammatory in 74%; autoantibodies were detected in 5%. CSF cytokine analysis (n=3) revealed increased CXCL-10 (IP-10), suggesting robust T-cell activation. The patients had AE (58%), myelitis (21%), acute disseminated encephalomyelitis (ADEM) (16%), and brainstem encephalitis (5%). All patients but 2 received immunomodulatory treatment. At last follow-up (median 130 days; range: 32-540), only one patient (5%) had a mRS>2.

Conclusion

CNS adverse events of COVID-19 vaccination appear to be very rare even at reference centers and consist mostly of antibody-negative AE, myelitis, and ADEM developing approximately 2 weeks after vaccination. Most patients improve following immunomodulatory treatment.

Economic Burden of Neurologic Toxicities Associated with Treatment of Patients with Relapsed or Refractory Diffuse Large B-Cell Lymphoma in the United States

BACKGROUND

Chimeric antigen receptor (CAR) T-cell therapy, which is approved for the treatment of relapsed or refractory diffuse large B-cell lymphoma (DLBCL), can be associated with potentially severe and costly neurologic adverse events (AEs).

OBJECTIVES

To develop an evidence-based list of treatment-related neurologic AEs in patients with relapsed or refractory DLBCL, including AEs related to CAR T-cell therapies, and to estimate the healthcare costs associated with these neurologic AEs in a real-world setting.

METHODS

We identified grade ≥3 neurologic AEs that occurred in ≥2% of patients by reviewing drug prescribing information and published clinical trials with therapies used for relapsed or refractory DLBCL. Data from 3 nationally representative claims databases were used to identify adults with relapsed or refractory DLBCL, who were eligible for the study if they received 1 of 4 types of therapy, including CAR T-cell therapy, high-intensity cytotoxic therapy, low-intensity cytotoxic therapy, or targeted therapies. The rates of neurologic AEs and total healthcare costs were calculated for patients with and without neurologic AEs within 30 days of treatment. The costs were inflated to 2019 first-quarter US dollars.

RESULTS

A total of 16 types of neurologic AEs were identified, including 13 events related to CAR T-cell therapy and 5 related to conventional immunochemotherapy regimens, with 2 overlapping event types. Of these AEs, 11 were included in the claims analysis, based on available diagnosis codes. Of the 11,098 adults with relapsed or refractory DLBCL in the study, 118 patients received CAR T-cell therapy, 9483 received a high-intensity cytotoxic therapy, 1259 received a low-intensity cytotoxic therapy, and 238 received a targeted therapy. A total of 299 (2.7%) patients had ≥1 neurologic AEs during the 30-day postindex period. Of these patients, 43 received CAR T-cell therapy (36.4% of the 118 CAR T-cell therapy users). The mean total healthcare cost was $71,982 higher for patients with neurologic AEs than for patients without neurologic AEs. The trend of higher costs in patients with neurologic AEs was consistent across the treatment groups and was most pronounced in CAR T-cell therapy users ($143,309; 95% confidence interval, $5838-$280,779).

CONCLUSION

Patients with relapsed or refractory DLBCL who had severe or life-threatening neurologic AEs incur substantially higher costs than their counterparts who do not have neurologic AEs, with the largest cost difference in patients who receive CAR T-cell therapy.

Human CD19-Targeted Mouse T Cells Induce B Cell Aplasia and Toxicity in Human CD19 Transgenic Mice

The clinical success of chimeric antigen receptor (CAR) T cell therapy for CD19+ B cell malignancies can be limited by acute toxicities and immunoglobulin replacement needs due to B cell aplasia from persistent CAR T cells. Life-threatening complications include cytokine release syndrome and neurologic adverse events, the exact etiologies of which are unclear. To elucidate the underlying toxicity mechanisms and test potentially safer CAR T cells, we developed a mouse model in which human CD19 (hCD19)-specific mouse CAR T cells were adoptively transferred into mice whose normal B cells express a hCD19 transgene at hemizygous levels. Compared to homozygous hCD19 transgenic mice that have ∼75% fewer circulating B cells, hemizygous mice had hCD19 frequencies and antigen density more closely simulating human B cells. Hemizygous mice given a lethal dose of hCD19 transgene-expressing lymphoma cells and treated with CAR T cells had undetectable tumor levels. Recipients experienced B cell aplasia and antigen- and dose-dependent acute toxicities mirroring patient complications. Interleukin-6 (IL-6), interferon γ (IFN-γ), and inflammatory pathway transcripts were enriched in affected tissues. As in patients, antibody-mediated neutralization of IL-6 (and IFN-γ) blunted toxicity. Apparent behavioral abnormalities associated with decreased microglial cells point to CAR-T-cell-induced neurotoxicity. This model will prove useful in testing strategies designed to improve hCD19-specific CAR T cell safety.