ABSTRACT
Background: Post-acute sequelae of SARS-COV-2 infection (PASC) is associated with cognitive impairment (CI) with unclear pathogenesis though blood brain barrier (BBB) impairment and excitotoxic injury appear significant. Post-acute sequelae of SARS-COV-2 infection (PASC) is associated with cognitive impairment (CI) with unclear pathogenesis though blood brain barrier (BBB) impairment and excitotoxic injury appear significant. We hypothesized that PASC CI patients would have brain inflammation and BBB disruption using advanced MR imaging. Method(s): In this prospective longitudinal study, 14 patients with PASC CI (mild and non-hospitalised) were enrolled (mean age of 45;10 F and 4 M) and 10 sex and age matched healthy controls. 13 had a follow up MR at 9-12 months (mean 10 months). All participants underwent DCE perfusion (an index of BBB integrity with Ktrans as the measurement), Diffusion Tensor Imaging (DTI) and single voxel MR spectroscopy (MRS) of the frontal cortex/white matter and the brainstem in addition to brain anatomical MRI. Between group analyses were used to determine which MRI outcomes were significantly different from controls in patients with PASC CI. Result(s): The PASCI CI group showed significantly increased (ie BBB impairment) Ktrans, and increased region (Frontal white matter and Brain Stem)-specific areas in the brain (p=< 0.005), reduction in NAA (ie neuronal injury) and mild reduction of Glx (ie excitotoxicity) in the frontal white matter and brain stem (p=0.004), and reduction in white matter integrity (increased diffusivity -greater radial and mean diffusivity). Increased Ktrans was correlated with increased both radial and mean diffusivity (r=0.9) in all tested brain regions. Ktrans significantly improved in the follow up MR (p= 002596 Z=-2.794872) with no difference between subjects and controls indicating BBB normalisation (p= 0.442418, z= -0.144841). White matter integrity also improved especially in the fractional anisotropy values in the executive networks (p=< 0.00045). MRS showed significant improvement in the NAA in the frontal white matter but Glx remain high as compared to the controls (p=0.0006). Conclusion(s): PASC CI was characterised by reversible diffuse BBB impairment, neuronal/axonal and excitotoxic injury. BBB impairment was associated with white matter disruption. These are suggestive biomarkers for the presence, severity and prognosis of PASC CI. Such biomarkers could underpin appropriate trial design and timing of intervention.
ABSTRACT
Background: Patients (pts) with indolent lymphomas are at increased risk of severe COVID-19 infection. We have shown limited seroconversion and live viral neutralisation (VN), but preserved COVID-specific T cell responses after 2 doses of mRNA COVID-19 vaccination in such pts. (Beaton, B ASH 2021, 149348). A 3rd vaccine dose to complete primary vaccination has since been recommended. Aims: To assess humoral & cellular immune responses to a 3rd COVID-19 (mRNA) vaccination in pts with follicular lymphoma (FL) & Waldenström Macroglobulinemia (WM), including assessment of response after pausing BTKi therapy in WM pts. Methods: Patients with WM, FL & healthy controls (HC) were enrolled in a prospective observational study to measure immune responses 21-28 days after a 3rd mRNA COVID-19 vaccine. Immune response was measured by mean fluorescence intensity (MFI) of anti-SARS-CoV-2 spike antibodies (ASAb) obtained using a high-sensitivity live cell assay, live VN to a panel of SARS-CoV-2 variants of concern, and CD4+ & CD8+ antigen-specific T cell responses. The associated TRIBECA (TReatment Interruption of BTKi to Enhance COVID-19 Antibody response) study sought to determine if a superior immune response could be gained by pause of BTKi therapy prior to and up to 4 weeks after 3rd vaccine dose. Patients were closely monitored during the BTKi pause with weekly clinical, full blood count and IgM assessments. WM pts receiving a 3rd dose while continuing on BTKi served as a control. Statistical analysis of medians between cohorts were compared by the non-parametric Mann-Whitney (Graphpad Prism). Comparison of medians between paired grouped data was assessed by 2-way ANOVA. Results: To date, 56 of 125 pts had their ASAb measured following 3rd vaccine dose administered between October 2021 and January 2022: 28 WM pts (including 6/9 WM pts on the BTKi pause sub-study), 24 FL pts and 4 HC. Median age was 68 years with 21 females and 35 males. Median follow up from 2nd dose was 140 days (range: 79- 170 days). In antibody responders, median MFI fell from 163042 (IQR 82663-249934) 28 days post 2nd dose to 52117 (IQR 19942-60973) (p<0.0001) immediately before the 3rd dose. Median MFI in all FL & WM pts pre- 3rd dose vaccine was 17111 (IQR 0-52650), rising significantly post 3rd dose to a median of 86730 (IQR 0-221937). Only 4/20 pts without measurable ASAb prior to the 3rd dose (2 WM, 2 FL) developed measurable ASAb following the 3rd dose: 16/20 patients (8 WM, 8FL, all treated) had no ASAb response. The median MFI in pts who underwent a BTKi treatment pause rose from 9151 (IQR 1671-21232) pre-3rd dose to 87720 (IQR 2785-152195) post 3rd dose, significantly higher than the median MFI in WM pts who did not pause their BTKi , which rose from 16769 (IQR 218-22447) pre- to 20252 (IQR 168-114262) post 3rd dose, (p = 0.016). Of the 5/125 with COVID infection in the study to date, only one patient (without measurable ASAb) in this 3-dose cohort had COVID, requiring intensive care support. Summary/Conclusion: Most WM & FL pts who responded to a 2nd dose COVID vaccine showed a decline in ASAb titre over time which increased following a 3rd mRNA vaccine. Only 20% of pts without detectable ASAb pre- 3rd dose showed improvement post 3rd dose, highlighting the importance of other COVID protection strategies in these pts. Although initial numbers are small, there may be a higher increment in ASAb when BTKi therapy is paused around the time of vaccination. Comprehensive immune analysis, including VN and T-cell response on the entire FL & WM cohort will be presented at the EHA congress.
ABSTRACT
Introduction Lymphoid malignancies are a risk factor for severe COVID-19. Vaccination with BNT162b2 protects the general population from severe disease, but recent studies have shown limited seroconversion after vaccination in patients with lymphoid malignancy. This reduced response is likely related to disease and treatment factors altering both humoral and cellular immunity. Assessing response in patients with the indolent lymphomas, Waldenström's Macroglobulinaemia (WM) and Follicular Lymphoma (FL), including cohorts on differing treatment regimens, may help elucidate some of these factors. Australia has had low prevalence of SARS-CoV-2 infection to date, affording a unique opportunity to assess efficacy to vaccination without the confounding impact of endemic infection. Methods Patients with WM and FL and controls were enrolled in a prospective study of immune response after two doses of BNT162b2 administered 21 days apart. The study had Human Research Ethics Committee approval and all patients gave informed consent prior to participation. Recruitment was targeted to obtain comparable proportions of controls to treatment cohorts. PBMC and sera were collected from participants immediately prior to the first dose (T1), at day 21 immediately prior to the second dose (T2), and day 49 (+/-7d) (T3). Immune response was measured by: flow cytometric detection of anti-SARS-CoV-2 spike antibodies (ASAb), performed using our recently validated flow cytometric live cell assay (Tea et.al. PLoS Medicine 2021) with increased sensitivity compared to currently available commercial ELISAs;live virus neutralisation to a panel of SARS-CoV-2 variants of concern;and CD4+and CD8+ antigenspecific T cell responses. Statistical analysis of medians between cohorts were compared by the Mann-Whitney non-parametric test using Graphpad Prism. Initial ASAb IgG data for T1 and T2 is presented here. Complete immune response data at all time points will be available for the ASH meeting. Results Eighty-five participants received their first dose of BNT162b2 from 18 May 2021 to 7 June 2021 with a second dose 21 days later: 72 lymphoma patients (WM and FL) and 13 age-matched healthy volunteers (controls). Of 37 with WM [19 (51.3%) female, median 71 years (IQR 63-74)] 9 were treatment naïve (WMN), 15 had received rituximab-chemotherapy (WMT), and 13 were currently treated with a Bruton Tyrosine Kinase inhibitor (BTKi): 5 ibrutinib, 8 zanubrutinib (WMB). Of 35 patients with FL [16 (45.7%) female, median 65 years (IQR 54-71)], 11 were treatment naïve (FLN), and 24 had received rituximab-chemotherapy (FLT). Of the 13 controls 8 (61.5%) were female, median age 72 years (IQR 57-74)]. No participants had detectable ASAb at T1, confirming no prior SARS-CoV-2 exposure. Figure 1 shows ASAb results at T2. The median mean fluorescence intensity (MFI) of healthy controls: 60802 (IQR 17565 -78443), is higher than all WM: 0 (IQR 0-15010) p<0.0001, and all FL patients: 1687 (IQR 0-25421) p=0.002, Fig 1A. The median MFI of controls was higher than WMN (p=0.036), but not higher than FLN (p=0.28). The median MFI of WMN: 20074 (IQR 5421-35695), is higher than WMB: 0 (IQR 0-4217) p=0.018, but not significantly higher than WMT: 0 (IQR 0-14356) p=0.13, Fig 1B. Median MFI of FLN: 31476 (IQR 19351-51317), is higher than FLT: 0 (IQR 0-32849) p=0.01, Fig 1B. Conclusion These early serological data show measurable ASAb in all healthy controls 21 days post first dose of BNT162b2 vaccination. Treatment naïve patients had a better response than treated patients, and this did not differ significantly to healthy controls in the FL cohort. In WM, patients on BTKi had a significantly reduced response compared to treatment-naïve patients. This same reduction was not observed in the chemotherapy-rituximab cohort, but the characteristics of early responders versus non-responders, including time since last therapy, is being analysed. FL patients treated with chemotherapy-rituximab had a significantly reduced response compared to the treatmentnaïve cohort. Time constraints before the submission deadline prevented reporting of all mature vaccination response data. Measurement of ASAb one month after second vaccination, live virus neutralisation to a panel of SARS-CoV-2 variants of concern, and CD4+ and CD8+ antigen-specific T cell responses at T1, T2 and T3, to fully characterise the immune response to BNT162b2, will be reported at the ASH meeting.
ABSTRACT
The adaptive immune system, regulated by CD4 T cells, is essential for control of many viral infections. Endemic coronavirus infections generally occur as short-term upper respiratory tract infections which in many cases appear to be cleared before adaptive immunity is fully involved, since adaptive immunity takes approximately 1.5-2 weeks to ramp up the response to a primary infection, or approximately 1 week for a recurrent infection. However, the adaptive immune response to SARS-CoV-2 infection will be critical to full recovery with minimal long-lasting effects, and to either prevention of recurrence of infection or at least reduced severity of symptoms. The detailed kinetics of this infection versus the dynamics of the immune response, including in vaccinated individuals, will largely determine these outcomes.