Memory T cells effectively recognize the SARS-CoV-2 hypermutated BA.2.86 variant.

T cells are critical in mediating the early control of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) breakthrough infection. However, it remains unknown whether memory T cells can effectively cross-recognize new SARS-CoV-2 variants with a broad array of mutations, such as the emergent hypermutated BA.2.86 variant. Here, we report in two separate cohorts, including healthy controls and individuals with chronic lymphocytic leukemia, that SARS-CoV-2 spike-specific CD4+ and CD8+ T cells induced by prior infection or vaccination demonstrate resilient immune recognition of BA.2.86. In both cohorts, we found largely preserved SARS-CoV-2 spike-specific CD4+ and CD8+ T cell magnitudes against mutated spike epitopes of BA.2.86. Functional analysis confirmed that both cytokine expression and proliferative capacity of SARS-CoV-2 spike-specific T cells to BA.2.86-mutated spike epitopes are similarly sustained. In summary, our findings indicate that memory CD4+ and CD8+ T cells continue to provide cell-mediated immune recognition to highly mutated emerging variants such as BA.2.86.

Local and Systemic Immunity During Five Vaccinations Against SARS-CoV-2 in Zanubrutinib-Treated Patients With Chronic Lymphocytic Leukemia.

Background: Patients with chronic lymphocytic leukemia (CLL) are vulnerable to coronavirus disease 2019 (COVID-19) and are at risk of inferior response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination, especially if treated with the first-generation Bruton's tyrosine kinase inhibitor (BTKi) ibrutinib. We aimed to evaluate the impact of the third-generation BTKi, zanubrutinib, on systemic and mucosal response to SARS-CoV-2 vaccination. Methods: Nine patients with CLL with ongoing zanubrutinib therapy were included and donated blood and saliva during SARS-CoV-2 vaccination, before vaccine doses 3 and 5 and 2 - 3 weeks after doses 3, 4, and 5. Ibrutinib-treated control patients (n = 7) and healthy aged-matched controls (n = 7) gave blood 2 - 3 weeks after vaccine dose 5. We quantified reactivity and neutralization capacity of SARS-CoV-2-specific IgG and IgA antibodies (Abs) in both serum and saliva, and reactivity of T cells activated with viral peptides. Results: Both zanubrutinib- and ibrutinib-treated patients had significantly, up to 1,000-fold, lower total spike-specific Ab levels after dose 5 compared to healthy controls (P < 0.01). Spike-IgG levels in serum from zanubrutinib-treated patients correlated well to neutralization capacity (r = 0.68; P < 0.0001) and were thus functional. Mucosal immunity (specific IgA in serum and saliva) was practically absent in zanubrutinib-treated patients even after five vaccine doses, whereas healthy controls had significantly higher levels (tested in serum after vaccine dose 5) (P < 0.05). In contrast, T-cell reactivity against SARS-CoV-2 peptides was equally high in zanubrutinib- and ibrutinib-treated patients as in healthy control donors. Conclusions: In our small cohort of zanubrutinib-treated CLL patients, we conclude that up to five doses of SARS-CoV-2 vaccination induced no detectable IgA mucosal immunity, which likely will impair the primary barrier defence against the infection. Systemic IgG responses were also impaired, whereas T-cell responses were normal. Further and larger studies are needed to evaluate the impact of these findings on disease protection.

Deficits in the IgG+ memory B-cell recovery after anthracycline treatment is confined to the spleen of rhesus macaques.

OBJECTIVES: Loss of vaccine-induced antibodies (Abs) after chemotherapy against paediatric acute lymphoblastic leukaemia (ALL) is common and often necessitates re-immunisation after cessation of treatment. Even so, some ALL survivors fail to mount or to maintain protective Abs. Germinal centres (GCs) are clusters of proliferating B cells in follicles of secondary lymphoid tissues (SLTs) formed during adaptive immune responses and the origins of long-lived memory B and plasma cells that are the source of Abs. Furthermore, productive GC reactions depend on T follicular helper (TFH) cells. To understand why chemotherapy induces deficits in Ab responses, we examined how SLTs were affected by chemotherapy. METHODS: Rhesus macaques were infused with either three cycles of the anthracycline doxorubicin or saline, followed by immunisation with a de novo and booster antigen. Spleen and lymph nodes were removed, and memory B, bulk T and TFH cells were examined. RESULTS: Despite adequate GC morphology, a diminished memory and IgG+ B-cell population along with diminished total and booster vaccine-specific IgG-producing memory B cells were noted in the spleens of macaques with past doxorubicin exposure compared to the saline-treated controls (P < 0.05). Intact bulk T and TFH cells were found in the SLTs of treated macaques, which displayed higher CD40L upregulation capacity by their splenic CXCR5+ helper T cells (P < 0.01). In contrast to the spleen, the immune cell populations studied were comparable between the lymph nodes of both saline- and doxorubicin-treated macaques. CONCLUSION: Our findings suggest that the splenic memory B-cell subset, compared to its lymph node counterpart, is more severely altered by anthracycline treatment.

Altered proportions of circulating CXCR5+ helper T cells do not dampen influenza vaccine responses in children with rheumatic disease.

Biological therapy options for the treatment of rheumatic disease target molecules that can affect the cross-talk between innate and adaptive immune responses upon vaccination. Influenza vaccination in children with rheumatic disease has been recommended, but there are only sparse data on the quality of vaccine responses from pediatric patients treated with biological therapy. We conducted an influenza vaccine study over 3 consecutive seasons where the antibody response to TIV was evaluated in children with PRD (n = 78), including both non-treated (n = 17) and treated (with methotrexate, TNF-inhibitors with or without methotrexate, or IL-inhibitors, n = 61) children as well as healthy age-matched controls (n = 24). Peripheral B cells, T and NK cell populations, as well as CXCR5+ (follicular) helper T cells (TFH) and chemokines involved in antibody responses were assessed prior to immunization in the same cohort. Data on disease duration, therapy and data on previous influenza vaccinations were retrieved. The proportion of circulating TFH cells were significantly lower in non-treated children with PRD compared to treated patients and healthy controls. The significantly lower proportion of TFH cells was mirrored by a marked significant increase in CXCL13 serum level, the ligand for CXCR5, with higher levels in non-treated children with PRD compared to treated patients and healthy controls. However, the proportion of TFH cells or CXCL13 level at the time of vaccination was not a predictor of the antibody response to TIV in this cohort of children. Children with PRD had an overall similar response to TIV as healthy children. Although not significant, children treated with TNF-inhibitors differed as a few children remained seronegative towards H3N2- and influenza B viruses after immunization. Our data show that children with PRD respond to TIV as healthy children. Furthermore, plasma CXCL13 levels did not correlate to the proportion of TFH cells in blood prior to immunisation, or to antibody responses following immunization.

Diverse effects on vaccine-specific serum IgG titres and memory B cells upon methotrexate and anti-TNF-α therapy in children with rheumatic diseases: A cross-sectional study.

OBJECTIVES: We aimed at a comprehensive evaluation of how anti-TNF-α therapy and methotrexate treatment interferes with B cell memory in children with Paediatric Rheumatic Disease (PRD), by evaluating existing B cell phenotypes, and preserved vaccine-specific memory B cells and IgG titres generated prior to disease and treatment. METHODS: In a cross-sectional study on children with PRD on various treatments, we measured titre levels and avidity strength of serum IgG specific against measles, rubella and tetanus. We also quantified transitional B cells and resting, atypical, and activated memory B cells with flow cytometry, and enumerated antigen-specific memory B cells with ELISpot. RESULTS: For children who had received a tetanus booster, patients treated with any disease-modifying anti-rheumatic drug (DMARD) had lower tetanus serum IgG compared to healthy controls and NSAID-treated patients. Patients without a measles booster had lower levels of measles-specific memory B cells, but all vaccine-specific memory B cells were preserved in patients with booster. We furthermore found that the mature B cell compartment was phenotypically similar between patients and healthy controls. CONCLUSIONS: We concluded that the general and vaccine-specific memory B cell compartment is well preserved in children with PRD and DMARD treatment, but that they might have lower serum tetanus IgG. We emphasize the importance for these children to follow the full vaccination schedule, and suggest to re-measure tetanus titres as they reach adulthood.