Humoral immunity to SARS-CoV-2 mRNA vaccination in multiple sclerosis: the relevance of time since last rituximab infusion and first experience from sporadic revaccinations.

INTRODUCTION: The effect of disease-modifying therapies (DMT) on vaccine responses is largely unknown. Understanding the development of protective immunity is of paramount importance to fight the COVID-19 pandemic. OBJECTIVE: To characterise humoral immunity after mRNA-COVID-19 vaccination of people with multiple sclerosis (pwMS). METHODS: All pwMS in Norway fully vaccinated against SARS-CoV-2 were invited to a national screening study. Humoral immunity was assessed by measuring anti-SARS-CoV-2 SPIKE RBD IgG response 3-12 weeks after full vaccination, and compared with healthy subjects. RESULTS: 528 pwMS and 627 healthy subjects were included. Reduced humoral immunity (anti-SARS-CoV-2 IgG <70 arbitrary units) was present in 82% and 80% of all pwMS treated with fingolimod and rituximab, respectively, while patients treated with other DMT showed similar rates as healthy subjects and untreated pwMS. We found a significant correlation between time since the last rituximab dose and the development of humoral immunity. Revaccination in two seronegative patients induced a weak antibody response. CONCLUSIONS: Patients treated with fingolimod or rituximab should be informed about the risk of reduced humoral immunity and vaccinations should be timed carefully in rituximab patients. Our results identify the need for studies regarding the durability of vaccine responses, the role of cellular immunity and revaccinations.

A man in his seventies with spinal cord injury, fever and delirium. / En mann i 70-årene med ryggmargsskade, feber og delirium.

INTRODUCTION: Spinal cord injury includes damage to the motor, sensory and autonomic nervous system. CASE PRESENTATION: A man in his seventies was admitted to hospital after an acute traumatic incomplete cervical spinal cord injury. Over the following weeks, he experienced multiple febrile episodes with CRP elevated to 100 ­ >300 mg/L, but few other symptoms. Two weeks after admission, he was febrile with neuropathic pain, and oxygen saturation spontaneously decreased from 98 % to 87 %. Chest X-ray showed pneumonia, which was treated with antibiotics. Four weeks after the injury he again experienced fever and increased spasticity. Clinical examination revealed dull abdominal pain on palpation in the left upper quadrant. The same day, a PEG placement procedure had been performed. CT abdomen, chest X-ray and microbiological investigation revealed no clear infectious origin. The patient was treated with antibiotic coverage for presumed abdominal infection, with successful recovery. Two months after his injury, the patient became febrile and delirious. Clinical examination revealed mild pain on palpation in the upper right quadrant. CT abdomen revealed cholecystitis. DISCUSSION: Diagnosis of acute serious illness in a patient with spinal cord injury may be challenging due to scarce and atypical clinical presentation. Prevalence of gallstones is increased after spinal cord injury.

Hospitalisations and humoral COVID-19 vaccine response in vaccinated rituximab-treated multiple sclerosis patients.

BACKGROUND: Patients with multiple sclerosis (MS) treated with anti-CD20 therapies such as rituximab may have increased risk of severe COVID-19 disease. Vaccination induces protective immunity, but humoral vaccine response is known to be attenuated in rituximab-treated MS-patients-patients, which has indicated a need for real world data on severe morbidity and mortality from COVID-19 after vaccination. METHODS: Rituximab-treated patients treated at Haukeland University Hospital were identified through the National MS Registry and invited to participate in the study by giving a consent and providing a blood sample 3 weeks or later after ordinary COVID-19- vaccination, i.e. 2 doses given with a standard interval of 3 weeks. Blood samples were analysed with Enzyme-Linked Immunosorbent assay (ELISA) to evaluate humoral vaccine response with screening test against receptor-binding domain (RBD) and confirmatory Spike IgG-specific ELISA. A haemagglutination test (HAT) was performed as a marker of neutralizing antibodies. Patient serum concentration of rituximab were quantified using liquid chromatography tandem mass spectrometry (LC-MS/MS). Registry data from the Norwegian MS registry and information on hospitalization from patient records were collected and linked to laboratory results. RESULTS: 111 patients were included in the study. A total of 7 (6.3%) were hospitalized due to COVID-19 disease during the observation period. No patient was admitted to ICU and there were no deaths. 34.2% did not have detectable titre of SARS CoV-2 Spike IgG antibodies, 72.1% did not have a detectable titre of SARS CoV-2 RBD antibodies, and 88.2% did not have a detectable HAT titre. There was a correlation between hospitalisation and the absence of SARS CoV-2 Spike IgG antibody titre, and between hospitalisation and MS disease duration, as well as between spike IgG antibody titre and CD19 B-cell count, time since last rituximab infusion, cumulative rituximab treatment time and total IgG level in the patients. CONCLUSION: A substantial proportion of rituximab-treated MS-patients-patients did not have detectable humoral vaccine responses after 2 doses of COVID-19 vaccination. Despite this, the cumulative percentage of patients hospitalized with COVID-19 disease throughout the observation period of 22 months was low, and no patients required ICU treatment. The results support that vaccinated MS-patients treated with rituximab have a protective effect against serious Covid-19 infection.

Predictors of hospitalization due to infection in rituximab-treated MS patients.

BACKGROUND: Rituximab is extensively used off-label to treat multiple sclerosis (MS), and long-term vigilance for adverse events is needed. This study was conducted to determine frequencies and predictors of hematological adverse events, including hypogammaglobulinemia, severe lymphopenia, neutropenia, and infections leading to hospitalization. METHODS: This retrospective cohort study included all patients with MS initiating rituximab treatment at Haukeland University Hospital between January 1st, 2017, and July 1st, 2021. Patients were followed by clinical monitoring and repeated blood sampling every six months. Clinical outcomes and laboratory results were retrieved from the Norwegian MS Registry and Biobank and the patient administrative system at Haukeland University Hospital. RESULTS: Five hundred and fifty-six patients were included, 515 with relapsing-remitting MS (RRMS) and 41 with progressive MS. Overall, 33 patients (5.9%) experienced 56 episodes of infections requiring hospital admission. Sixty patients (10.8%) had confirmed hypogammaglobulinemia, 17 (3.1%) had confirmed severe lymphopenia, and 10 (1.8%) had confirmed severe neutropenia. Predictors of infection requiring hospital admission were progressive MS (adjusted OR (aOR): 4.81; 95%CI: 1.25-18.48), duration of treatment with rituximab (aOR: 1.52; 95%CI: 1.11-2.09) and confirmed severe lymphopenia (aOR: 13.58; 95%CI: 3.41-54.06) and neutropenia (aOR: 13.40; 95%CI: 2.93-61.25). Of the hematological abnormalities, only hypogammaglobulinemia was associated with treatment duration (aOR: 1.35; 95%CI: 1.09-1.69). CONCLUSION: The risk of hospitalization due to infection is associated with time on rituximab treatment, in patients with lympho- or neutropenia, and in patients with primary progressive MS. We observed a time-dependent decline in IgG values, in contrast to neutrophil and lymphocyte count, suggesting a cumulative dose-dependent response. These predictors can assist clinicians in assessing and monitoring MS patients receiving rituximab.

Risk of fingolimod rebound after switching to cladribine or rituximab in multiple sclerosis.

BACKGROUND: A sudden onset of extensive disease activity, including severe clinical relapse and extensive brain or spinal magnetic resonance imaging (MRI) lesions, termed "rebound" disease activity has been reported after withdrawal of fingolimod in patients with multiple sclerosis (MS). OBJECTIVE: To compare the risk of rebound after switching from fingolimod to cladribine or rituximab in MS. METHODS: All patients switching from fingolimod to cladribine or rituximab were included in a retrospective cohort study utilizing prospectively collected data from two university hospitals with different treatment strategies. RESULTS: A total of 73 patients with at least 6 months follow-up after switching were identified, 33 patients had switched from fingolimod to cladribine and 40 patients to rituximab. No patients in the rituximab group and seven (21.1%) in the cladribine group qualified for rebound disease activity. Ten (30.3%) of the patients using cladribine and five (12.5%) of the patients using rituximab experienced a relapse. MRI disease activity was seen in 18 (54.5%) and eight (20.0%) of the patients using cladribine and rituximab, respectively. Younger age and previous high relapse rate were associated with increased risk of rebound in the cladribine group. CONCLUSIONS: We identify a lower risk of rebound during the first year after switching from fingolimod to rituximab compared to cladribine, indicating a better initial clinical outcome with the former treatment strategy.

Safety and efficacy of rituximab as first- and second line treatment in multiple sclerosis - A cohort study.

BACKGROUND: Rituximab is increasingly used as off-label therapy in multiple sclerosis (MS). More data are needed on safety and efficacy of rituximab, particularly in cohorts of de novo patients and patients in early therapy escalation. OBJECTIVE: To investigate the safety and efficacy of off-label treatment with rituximab in an MS-cohort of predominantly de novo patients or as therapy escalation. METHODS: We retrieved safety and efficacy data from the Norwegian MS-registry and biobank for all MS-patients treated with rituximab at Haukeland University Hospital, Bergen, Norway, during a four year period. RESULTS: In the 365 MS-patients (320 relapsing-remitting MS (RRMS), 23 secondary progressive MS (SPMS), and 22 primary progressive MS (PPMS)), the overall annualized relapse rate (ARR) was 0.03 and annualized drug discontinuation rate (ADDR) was 0.05. NEDA-3 was achived in 79% of patients with available data (n=351). Sixty-one patients experienced infusion-related adverse events of which two were serious (CTCAE grade 3-4). Eighteen patients experienced serious non-infusion related adverse events, of which 16 were infections. Infections (n = 34; 9.3%, CTCAE grade 2-5), hypogammaglobulinemia (n = 19, 5.2%) and neutropenia (n = 16; 4.4%) were the most common non-infusion-related adverse events. CONCLUSION: Rituximab was a safe and highly efficient disease modifying therapy in this cohort of MS-patients; however, infections and neutropenia need to be monitored.