ABSTRACT
Background: Bing-Neel syndrome (BNS) is a rare complication of lymphoplasmacytic lymphoma (LPL) comprising LPL infiltration in the central nervous system (CNS). Clinical and radiological features are diverse;the diagnosis is confirmed by cerebrospinal fluid (CSF) analysis using immunological and molecular techniques. Rarely, a tissue biopsy is required. The pattern of presentation including systemic involvement and CSF features inform treatment strategies, which include CNS-penetrating therapies. Aims: To evaluate the diagnostic characteristics of patients with BNS and their influence on therapy. Methods: Data from patients referred between 2011-2021 for management of BNS to our academic neurohaematology centre were retrospectively reviewed. Those with imaging features alone or where it was not possible to distinguish from high-grade transformation were excluded. Results: Thirty-five patients (22 male, 13 female) were identified. Median age at diagnosis of BNS was 65 years (range 48-85). All patients were symptomatic. In 12 patients (34%) BNS was the de novo presentation of the IgM-related disorder, of which 3 (25%) had no detectable bone marrow (BM) infiltration of LPL at diagnosis. Approximately half (17;49%) had previously received therapy for LPL;median time to BNS diagnosis in these was 49 months (range 3-125). At BNS diagnosis, BM involvement with LPL ranged from 0-95%. More than half (14/26;54%) had <10% infiltrate and almost a fifth (4/26) >60%. All patients had leptomeningeal involvement and 8 (23%) additionally had parenchymal CNS disease. The majority had kappa light-chain predominance: IgMκ (n=26), non-IgMκ (n=5), IgMλ (n=3), one unknown. The BNS diagnosis was made on CSF analysis (n=28;80%), leptomeningeal tissue biopsy (n=3;9%) where CSF was non-informative, or by expert opinion based on supportive clinical, radiological and non-definitive CSF features (n=4;11%). Of those with a diagnosis based on CSF studies, B-cell clonality was confirmed by flow cytometry (27/28;96%), MYD88L265P mutation (18/28;64%) and immunoglobulin gene rearrangement (12/28;43%). In 22 samples with a full dataset, median CSF white cell count was 25/ul (1-233), CSF protein 1.69g/l (0.35-6), CSF IgM 9.49mg/l (1.07-61.5). The majority were treated with intensive regimens (rituximab, methotrexate (MTX), cytarabine (ARA-C) + thiotepa/idarubicin;n=30) due to the presence of CNS disease bulk and clinical need, and less commonly ibrutinib (n=3), bendamustine-rituximab (BR, n=1);one patient had intrathecal therapy (MTX, ARA-C) at the height of the COVID pandemic. Of those who received 2 cycles of intensive chemotherapy, 3 had >4 cycles followed by BCNU/thiotepa autologous stem cell transplant;10 proceeded to 'consolidation' (indefinite) ibrutinib to limit intensive chemotherapy or tackle systemic disease. At a median follow up of 26 months (range 1-121), median survival was not reached;2-year overall survival was 91% (95% CI 74-97). Three patients died during treatment (1 invasive fungal infection post COVID-19 during ibrutinib consolidation post MTX/ARA-C based therapy) and 2 during MTX-ARA-C based therapy;7 patients relapsed or progressed and were treated with ibrutinib: 1 relapsed after ibrutinib use, 1 patient was intolerant of ibrutinib and switched to BR. Image: Summary/Conclusion: Our cohort confirms that BNS may present with leptomeningeal disease and/or parenchymal disease, de novo and without systemic disease. Overall outcomes are excellent with intensive regimens, consolidated with or followed by ibrutinib;however, there are treatment-related toxicities emphasising the need for a tailored approach.
ABSTRACT
Background: Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract characterized by immune dysregulation and decreased T cell receptor (TCR) repertoire diversity. Patients with immune-mediated disorders such as IBD have attenuated convalescent antibody responses after COVID-19 infection. We sought to understand the immune configuration associated with high versus low convalescent SARS-CoV- 2 antibodies in patients with IBD using single-cell immunophenotyping. Methods: We performed a study of 9 patients with IBD who were SARS-CoV-2 convalescent (recovered from COVID-19 and converted RNA positive to negative) and 9 matched SARS-CoV-2 naïve controls (no prior COVID-19, confirmed RNA negative). We measured plasma SARS-CoV- 2 antibody (N protein IgG, S1RBD IgG, S1RBD IgA) levels from patients with IBD two months after recovering from COVID-19 (RNA negative). We selected three patients with the highest SARS-CoV-2 antibodies and three matched (for age, sex, IBD subtype and disease activity, medications, COVID-19 severity) patients with the lowest antibodies and performed their peripheral blood mononuclear cell (PBMC) single-cell transcriptomics with paired TCR and BCR sequencing using 10X Genomics. Normalization, dimensionality reduction, and clustering were performed using Seurat. TCR and BCR immune repertoire analyses were performed using Immunarch. Results: SARS-CoV-2 convalescent patients with IBD had detectable but variable SARS-CoV-2 antibody levels (range 0-469 U/mL), whereas SARSCoV- 2 naïve IBD patients had no detectable antibodies. The mean SARS-CoV-2 antibody concentration among the three IBD patients with the highest and three patients with the lowest groups differed by more than 10-fold (206.0 vs 17.5 U/mL, P<0.001). PBMC singlecell immunophenotyping revealed decreased naïve CD4+ T cell and increased CD14+ monocyte and memory CD4+ T cell proportions in IBD patients in the low versus high SARSCoV- 2 antibody group. There were higher numbers of HLA-DQA1+ B cells and CD8 T cells and lower GPR183+ B cells and CD8 T cells in the high SARS-CoV-2 antibody group. There was a trend towards decreased TCR and BCR repertoire diversity in the low SARS-COV-2 antibody group. Finally, we identified immunoglobulin gene signatures (IGHV1-69D/IGLV3- 25, IGHV3-48, IGHV3-7/IGKV41/IGLV1-47, IGHV3-7/IGKV4-1, IGHV3-7/IGKV4-44) that were enriched only in the high SARS-CoV-2 antibody group. Conclusions: Single-cell immunophenotyping of PBMC from convalescent patients with IBD reveal differences in CD4+ T cell, CD14+ monocyte, and HLA-DQA1+ and GPR183+ B and CD8 T cell immunophenotypes, immune repertoire diversity, and immunoglobulin gene signatures in patients with high versus low SARS-CoV-2 antibody levels.(Figure Presented)Figure 1. SARS-COV-2 Antibodies in Convalescent Patients with IBD and Single-Cell Immunophenotypes. A) SARS-COV-2 antibody levels in COVID-19 convalescent versus SARS-CoV-2 naïve patients with IBD B) T-SNE plot of PBMC immunophenotypes in all convalescent patients with IBD C) Differences in proportion of single-cell PBMC immunophenotypes in high versus low SARS-COV-2 antibody patients D) Differences in HLA-DQA1 and GPR183 immunophenotypes in high versus low SARS-COV-2 antibody patients.
ABSTRACT
It is unclear whether individuals with enormous diversity in B cell receptor repertoires are consistently able to mount effective antibody responses against SARS-CoV-2. We analyzed antibody responses in a cohort of 55 convalescent patients and isolated 54 potent neutralizing monoclonal antibodies (mAbs). While most of the mAbs target the angiotensin-converting enzyme 2 (ACE2) binding surface on the receptor binding domain (RBD) of SARS-CoV-2 spike protein, mAb 47D1 binds only to one side of the receptor binding surface on the RBD. Neutralization by 47D1 is achieved independent of interfering RBD-ACE2 binding. A crystal structure of the mAb-RBD complex shows that the IF motif at the tip of 47D1 CDR H2 interacts with a hydrophobic pocket in the RBD. Diverse immunoglobulin gene usage and convergent epitope targeting characterize neutralizing antibody responses to SARS-CoV-2, suggesting that vaccines that effectively present the receptor binding site on the RBD will likely elicit neutralizing antibody responses in a large fraction of the population.