T cell-based therapies have shown remarkable efficacy in multiple myeloma (MM), yet the disease remains largely incurable. Here, we investigated the constant domains of the immunoglobulin heavy chain (IgH) as novel targets for therapeutic T cell receptors (TCRs), after confirming high and homogeneous IGH expression in >95% of MM patients. MM cells secrete excessive monoclonal immunoglobulins (M-proteins) that drive complications but are inaccessible to CAR T-cell or antibody targeting. Peptides from IgA and IgG constant regions were eluted from HLA-A*02:01, and reactive TCRs were isolated from healthy donors using allo-HLA-A*02:01 presentation to circumvent self-tolerance. T cells engineered with two TCRs specific for IgA or IgG passed a stringent multi-tier safety screen and selectively eliminated MM cells from 20 HLA-A*02:01+ patients secreting the relevant IgH in vitro. In vivo, IgA-TCR T cells eradicated IgA+HLA-A*02:01+ MM cells in xenograft models and reduced circulating IgA in humanized mice. These findings establish immunoglobulin constant domains as viable TCR targets in MM, potentially making ~40% of patients of European descent eligible for TCR T cell therapy, and extension to additional HLA alleles could further broaden eligibility. The approach may also be applicable to lymphoma and antibody-mediated autoimmune diseases.

Chronically ill patients with a weak immune system are at increased risk of severe infections, often as a result of immunomodulatory therapy rather than the underlying disease. Many patients in this group exhibit reduced vaccine responses and require tailored vaccination regimens. Following the launch of the national Adult Immunisation Programme, all doctors must stay abreast of current guidance on vaccination in immunosuppressed patients. This clinical review article summarises interdisciplinary knowledge on patients with a reduced vaccine response.

Abstract Background Coronavirus outbreaks remain a persistent threat to global health, and vaccines based primarily on spike-specific immune responses are susceptible to antigenic variation. T-cell immunity directed against conserved internal viral proteins may provide a complementary and more variant-tolerant strategy for next-generation coronavirus vaccines. Methods We combined machine learning–guided antigen prioritization with ex vivo functional immunological validation to identify conserved non-spike T-cell targets across betacoronaviruses. Candidate sequences were screened for immunogenicity using primary human peripheral blood mononuclear cells from healthy donors using intracellular cytokine staining and activation-induced marker assays. Top-ranked conserved regions were incorporated into multiepitope mRNA constructs, and their intracellular expression and HLA class I presentation were confirmed by immunopeptidomics. Immunogenicity was further evaluated ex vivo and in vivo using mRNA immunization of mice and T-cell FluoroSpot assays. Findings Across a panel of 97 peptides derived from 19 viral proteins, evolutionary conservation across distinct betacoronavirus taxa was strongly associated with functional T-cell immunogenicity in human donors. Highly conserved peptides elicited significantly stronger and more frequent CD4⁺ and CD8⁺ T-cell responses than taxon-restricted peptides. Multiepitope mRNA constructs encoding conserved regions were efficiently expressed and presented on HLA class I molecules and induced T-cell responses in human PBMCs. In mice, mRNA immunization with conserved multiepitope constructs generated robust interferon-γ– and interleukin-2–producing T-cell responses that exceeded those induced by unconserved control constructs. Interpretation These results link evolutionary conservation to functional cellular immunogenicity and demonstrate the feasibility of multiepitope mRNA delivery for inducing conserved coronavirus-directed T-cell responses. Although protective efficacy remains to be established, conservation-guided antigen selection represents a scalable strategy for developing T-cell–focused vaccines with broad lineage coverage, supporting pandemic preparedness beyond spike-centered immunity. Funding The research was supported by CEPI, NEC, University of Oslo and Oslo university hospital. Research in context Evidence before this study Prior coronavirus vaccine development has focused predominantly on spike protein–directed neutralizing antibodies. While highly effective against matched strains, spike-centered immunity is vulnerable to antigenic drift and lineage-specific escape. Multiple observational and experimental studies have shown that T-cell responses, particularly against internal viral proteins, are more conserved and correlate with reduced disease severity and cross-variant recognition. Epitope prediction algorithms and immunoinformatics approaches have been widely used to nominate candidate T-cell targets; however, systematic functional validation of conserved non-spike antigens across betacoronaviruses in primary human immune systems, combined with antigen presentation data and in vivo vaccine testing, has remained limited. Searches of PubMed and bioRxiv up to December 2025 using terms including “coronavirus T-cell vaccine,” “conserved coronavirus epitopes,” “betacoronavirus cross-reactive T cells,” and “mRNA T-cell vaccine” identified studies demonstrating cross-reactive T-cell immunity and computational epitope selection, but few integrated machine-learning–guided antigen prioritization with ex vivo human functional screening, immunopeptidomics, and in vivo mRNA immunization in a unified workflow. Added value of this study This study provides an integrated experimental and computational framework for identifying and validating conserved non-spike T-cell antigens across betacoronaviruses. We functionally screened a panel of candidate peptides derived from multiple viral proteins and demonstrated that evolutionary conservation across species is strongly associated with T-cell immunogenicity. We further demonstrate that multiepitope mRNA constructs encoding these top-ranked conserved regions can be intracellularly expressed, presented on HLA class I molecules to induce polyfunctional T-cell responses in primary human PBMCs. Finally, in vivo mRNA immunization in mice induces robust interferon-γ and interleukin-2 T-cell responses exceeding those induced by unconserved control constructs. Together, these findings link evolutionary conservation to functional cellular immunogenicity and extend beyond in silico prediction by demonstrating antigen processing, presentation, and immunogenicity across human and murine systems. Implications of all the available evidence Collectively, the available evidence indicates that T-cell immunity directed toward conserved internal coronavirus proteins represents a complementary and potentially more variant-tolerant axis of vaccine design than spike-only strategies. Our findings suggest that evolutionary conservation can serve as a practical selection principle for prioritizing T-cell antigens with broad lineage coverage and that multiepitope mRNA delivery is a feasible platform for inducing such responses. While direct protection and heterologous challenge studies will be required to establish clinical efficacy, the integration of computational prioritization with functional validation supports a scalable approach to pandemic preparedness that may be applicable to other rapidly evolving viral families.

ABSTRACT:Resistance to B-cell-targeted therapies in immune thrombocytopenia (ITP) has been linked to persistence of autoantibody-producing CD38+ long-lived plasma cells. CD38 antibody daratumumab has been proposed as a potential therapy for ITP. This multicenter, open-label, phase 2 study evaluated safety and efficacy of daratumumab in 21 patients with previously treated ITP. Following a safety run-in, 2 dosing cohorts received 8 and 10 subcutaneous injections of 1800 mg daratumumab weekly, respectively. Primary end points were safety and response (2 consecutive platelet counts ≥50 × 109/L at week 12 for the safety run-in/cohort 1, and at week 16 for cohort 2). At baseline, median platelet count was 17 × 109/L, median number of prior therapies was 4. Most treatment-emergent adverse events were transient grade 1 to 2, most commonly infections (38%). Two patients (4.7%) experienced grade 3 adverse events, 1 infusion-related reaction, and 1 severe acute respiratory syndrome coronavirus 2 infection with acute renal failure. Ten patients (48%) met the primary efficacy end point. Sustained response (2 consecutive platelet counts ≥50 × 109/L at week 24) was achieved in 8 patients (38%), of whom 2 later relapsed. Response and relapse rates did not differ between cohorts. Patient-reported quality of life measured by 36-Item Short-Form Health Survey improved in responding patients. Daratumumab decreased immunoglobulin levels in all patients, and substantially reduced CD38+ cells in peripheral blood and bone marrow. There was no significant difference in antiplatelet antibodies between responders and nonresponders. This study confirms CD38 as an important target in ITP. This trial was registered at clinicaltrials.gov as #NCT04703621, and at the European Clinical Trial Register (EudraCT #2019-004683-22).

Patients with Inflammatory Bowel Disease (IBD) undergoing immunosuppressive therapies face heightened susceptibility to severe COVID-19. An in-depth understanding of systemic inflammation and cellular immune responses after SARS-CoV-2 vaccination and breakthrough infections (BTI) is required for optimizing vaccine strategies in this population.While the prevalence of high serological responders post- third COVID-19 vaccine dose was lower, and the antibody waning was higher in IBD patients than in healthy donors (HD), IBD patients showed an increase in anti-RBD Wild Type IgG levels and cross-reactive Spike -specific memory B cells following BTI. However, there was no significant enhancement in cellular immune responses against anti-SARS-CoV-2 post-BTI, with responses instead characterized by activation of SARS-CoV-2 specific and also bystander CD8 T cells. These results suggest a complex interaction between chronic inflammation in IBD and the generation of new immune responses, highlighting the need for tailored vaccine regimens and anti-inflammatory therapies to boost cellular immunity against SARS-CoV-2.

BACKGROUND:The Bari-SolidAct randomized controlled trial compared baricitinib with placebo in patients with severe COVID-19. A post hoc analysis revealed a higher incidence of serious adverse events (SAEs) among SARS-CoV-2-vaccinated participants who had received baricitinib. This sub-study aimed to investigate whether vaccination influences the safety profile of baricitinib in patients with severe COVID-19. METHODS:Biobanked samples from 146 participants (55 vaccinated vs. 91 unvaccinated) were analysed longitudinally for inflammation markers, humoral responses, tissue viral loads, and plasma viral antigens on days 1, 3, and 8. High-dimensional analyses, including RNA sequencing and flow cytometry, were performed on available samples. Mediation analyses were used to assess relationships between SAEs, baseline-adjusted biomarkers, and treatment-vaccination status. FINDINGS:Vaccinated participants were older, more frequently hospitalized, had more comorbidities, and exhibited higher nasopharyngeal viral loads. Baricitinib treatment did not affect antibody responses or viral clearance, but reduced markers of T-cell and monocyte activation compared to placebo (sCD25, sCD14, sCD163, sTIM-3). Age, baseline levels of plasma viral antigen, and several inflammatory markers, as well as IL-2, IL-6, Neopterin, CXCL16, sCD14, and suPAR on day 8 were associated with the occurrence of SAEs. However, mediation analyses of markers linked to SAEs, baricitinib treatment, or vaccination status did not reveal statistically significant interactions between vaccination status and SAEs. INTERPRETATION:This sub-study did not identify any virus- or host-related biomarkers significantly associated with the interaction between SARS-CoV-2 vaccination status and the safety of baricitinib. However, caution should be exercised due to the moderate sample size. FUNDING:EU Horizon 2020 (grant number 101015736).

Multiple myeloma (MM) cells secrete high levels of immunoglobulin and are therefore addicted to mechanisms that maintain proteome homeostasis (proteostasis). While proteasome inhibitors that target the degradative aspect of proteostasis have proven effective, only limited attempts have been made to target protein secretion. Here we show that the receptor tyrosine kinase LTK is a regulatory node in the proteostasis network that responds to secretory load and helps cells maintain a high secretory output. LTK is a highly similar paralog to ALK and by repurposing existing ALK inhibitors, we demonstrate that targeting LTK causes immunoglobulin retention, ER stress and subsequent apoptosis of primary MM cells, even in patients refractory to proteasome inhibitors. Thus, LTK is a novel therapeutic target in the biosynthetic pathway of proteostasis, with significant potential for MM treatment.

Background As most people now have established hybrid immunity, the need for regular, updated SARS-CoV-2 vaccine boosters in patients with immune-mediated inflammatory diseases (IMIDs) is unclear. The study aim was to assess humoral and cellular immunogenicity of a fifth bivalent vaccine dose in patients with IMID on tumour necrosis factor inhibitors (TNFi). Methods In the longitudinal, observational Nor-vaC study, we assessed anti-spike and neutralising antibodies against Wuhan, Omicron BA.1 and BA.4, as well as frequency and polyfunctionality of responding T cells, following a fourth monovalent and a fifth bivalent (BA.1 or BA.4/5) vaccine dose in patients with or without hybrid immunity using TNFi. Findings Between December 17, 2021, and June 20, 2023, 456 infection-naive patients with IMIDs using TNFi received a fourth vaccine dose and were otherwise eligible for inclusion. A total of 373/456 (82%) received a fifth vaccine dose, of these 190/373 (51%) had hybrid immunity defined as having had COVID-19 between the fourth and fifth dose. In patients with hybrid immunity, the fifth dose did not induce improved humoral responses compared to infection, neither with BA.1 (median anti-spike antibody concentrations 23,244 IU/ml (IQR 15,138-45,233) vs 36,341 IU/ml (11,887-53,710), p = 0.52) nor BA.4/5 (31,693 IU/ml (15,176-54,186), p = 0.30). Comparison of neutralising antibodies yielded similar results. In infection-naive patients, a fifth BA.4/5 vaccine, but not the BA.1, induced slightly higher humoral responses (18,890 IU/ml (6494-50,211)) compared to the fourth dose (7304 IU/ml (3245-17,260), p < 0.0001). CD8 T cell responses remained stable following a fourth dose (median frequency of spike-specific cells 0.039% (IQR 0.010-0.14)), infection (0.058% (0.026-0.17)) and a fifth dose (0.058% (0.013-0.20). Interpretation In patients on TNFi with hybrid immunity, there was no immunological benefit of an updated fifth SARS-CoV-2 booster dose. Stable CD8 cellular responses following four doses indicate established protective immunity. Patients whose only risk factor is TNFi may in future follow vaccine recommendations for the general population. Copyright (c) 2024 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The COVID-19 pandemic posed a challenge for people living with HIV (PLWH), particularly immune non-responders (INR) with compromised CD4 T-cell reconstitution following antiretroviral therapy (CD4 count <350 cells per mm3). Their diminished vaccine responses raised concerns about their vulnerability to SARS-CoV-2 breakthrough infections (BTI). Our in-depth study here revealed chronic inflammation in PLWH and a limited anti-Spike IgG response after vaccination in INR. Nevertheless, the imprinting of Spike-specific B cells by vaccination significantly enhanced the humoral responses after BTI. Notably, the magnitude of cellular CD4 response in all PLWH was comparable to that in healthy donors (HD). However, the polyfunctionality and phenotype of Spike-specific CD8 T cells in INR differed from controls. The findings highlight the need for additional boosters with variant vaccines, and for monitoring ART adherence and the durability of both humoral and cellular anti-SARS-CoV-2 immunity in INR.

BACKGROUND:B-cell acute lymphoblastic leukemia (B-ALL) is classified into subgroups based on known driver oncogenes and molecular lesions, including translocations and recurrent mutations. However, the current diagnostic tests do not identify subtypes or oncogenic lesions for all B-ALL samples, creating a heterogeneous B-ALL group of unknown subtypes.METHODS:We sorted primary adult B-ALL cells and performed transcriptome analysis by bulk RNA sequencing (RNA-seq).RESULTS:Transcriptomic analysis of an adult B-ALL cohort allowed the classification of four patient samples with subtypes that were not previously revealed by standard gene panels. The leukemia of two patients were of the DUX4 subtype and two were CRLF2+ Ph-like B-ALL. Furthermore, single nucleotide variant analysis detected the oncogenic NRAS-G12D, KRAS-G12D, and KRAS-G13D mutations in three of the patient samples, presenting targetable mutations. Additional oncogenic variants and gene fusions were uncovered, as well as multiple variants in the PDE4DIP gene across five of the patient samples.CONCLUSION:We demonstrate that RNA-seq is an effective tool for precision medicine in B-ALL by providing comprehensive molecular profiling of leukemia cells, identifying subtype and oncogenic lesions, and stratifying patients for appropriate therapy.

BACKGROUND:During the initial wave of the COVID-19 pandemic, there was a surprisingly low incidence of SARS-CoV-2 among People Who Use Drugs (PWUD) in Oslo, Norway, despite their heightened vulnerability regarding risk of infection and severe courses of the disease.This study aims to investigate the seroprevalence of SARS-CoV-2 antibodies among PWUD, their antibody responses to relevant virus infections and COVID-19 mRNA vaccines, and their vaccination coverage compared to the general population. METHODS:Conducted as a prospective cohort study, data was collected from residents in six institutions for homeless PWUD and users of a low-threshold clinic for opioid agonist treatment. Ninety-seven participants were recruited for SARS-CoV-2 seroprevalence analysis. Additional two participants with known positive SARS-CoV-2 test results were recruited for further analyses. Twenty-five participants completed follow-up. Data included questionnaires, nasal swabs and blood samples. Data on vaccination coverage was obtained from the National Vaccine Register. Serologic methods included detection of antibodies to relevant virus proteins, neutralizing antibodies to SARS-CoV-2, antibodies to the full-length spike protein, and receptor-binding domain from SARS-CoV-2. RESULTS:Among PWUD, antibodies to SARS-CoV-2 were detected in 2 out of 97 samples before vaccines against SARS-CoV-2 were available, comparable to a 2.8% frequency in population-based screening. Levels of serum antibodies to seasonal coronaviruses and Epstein-Barr-Virus (EBV) in PWUD were similar to population-based levels. After the second vaccine dose, binding and neutralizing antibody levels to SARS-CoV-2 in PWUD were comparable to controls. Eighty-four of PWUD received at least one dose of COVID-19 mRNA vaccine, compared to 89% in the general population. CONCLUSION:Results indicate that PWUD did not exhibit increased SARS-CoV-2 seroprevalence or elevated serum antibodies to seasonal coronaviruses and EBV. Moreover, vaccine responses in PWUD were comparable to controls, suggesting that vaccination is effective in conferring protection against SARS-CoV-2 also in this population.

BACKGROUND:Understanding cellular responses to SARS-CoV-2 immunisations is important for informing vaccine recommendations in patients with inflammatory bowel disease (IBD) and other vulnerable patients on immunosuppressive therapies. This study investigated the magnitude and quality of T cell responses after multiple SARS-CoV-2 vaccine doses and COVID-19 breakthrough infection. METHODS:This prospective, observational study included patients with IBD and arthritis on tumour necrosis factor inhibitors (TNFi) receiving up to four SARS-CoV-2 vaccine doses. T cell responses to SARS-CoV-2 peptides were measured by flow cytometry before and 2-4 weeks after vaccinations and breakthrough infection to assess the frequency and polyfunctionality of responding cells, along with receptor-binding domain (anti-RBD) antibodies. FINDINGS:Between March 2, 2021, and December 20, 2022, 143 patients (118 IBD, 25 arthritis) and 73 healthy controls were included. In patients with either IBD or arthritis, humoral immunity was attenuated compared to healthy controls (median anti-RBD levels 3391 vs. 6280 BAU/ml, p = 0.008) after three SARS-CoV-2 vaccine doses. Patients with IBD had comparable quantities (median CD4 0.11% vs. 0.11%, p = 0.26, CD8 0.031% vs. 0.047%, p = 0.33) and quality (polyfunctionality score: 0.403 vs. 0.371, p = 0.39; 0.105 vs. 0.101, p = 0.87) of spike-specific T cells to healthy controls. Patients with arthritis had lower frequencies but comparable quality of responding T cells to controls. Breakthrough infection increased spike-specific CD8 T cell quality and T cell responses against non-spike peptides. INTERPRETATION:Patients with IBD on TNFi have T cell responses comparable to healthy controls despite attenuated humoral responses following three vaccine doses. Repeated vaccination and breakthrough infection increased the quality of T cell responses. Our study adds evidence that, in the absence of other risk factors, this group may in future be able to follow the general recommendations for COVID-19 vaccines. FUNDING:South-Eastern Norway Regional Health Authority, Coalition for Epidemic Preparedness Innovations (CEPI), Norwegian Institute of Public Health, Akershus University Hospital, Diakonhjemmet Hospital.

Background: The SARS-CoV-2 virus mutates continuously, posing challenges for patients with immune-mediated inflammatory diseases (IMIDs) on tumour necrosis factor inhibitors (TNFi). These patients often have diminished vaccine responses and are at a higher risk for severe infections. The efficacy of the recommended mono- and bivalent vaccine boosters in this patient population remains unclear. Objectives: To assess the neutralizing capacity and serologic responses to SARS-CoV-2 in TNFi-treated IMID patients, after receiving a monovalent 4th vaccine dose and a bivalent 5th vaccine dose, including those with hybrid immunity. Methods: These analyses from the ongoing observational Nor-vaC study included TNFi-treated IMID patients who received either a 5th vaccine dose or experienced SARS-CoV-2 infection following a 4th vaccine dose (hybrid immunity). Blood samples were collected 2-4 weeks after the 4th monovalent vaccine dose and after either subsequent COVID-19 or a 5th bivalent dose (BA.1 or BA.4/5). Neutralizing antibody titres against three viral variants (Wuhan (WT), Omicron BA.1, and Omicron BA.4), and IgG anti-spike antibody levels, were analysed. Group comparisons were performed with Mann Whitney U test, and Spearman correlation. Results: From Dec 17, 2021, to Jun 20, 2023, 371 IMID patients (86 rheumatoid arthritis, 72 psoriatic arthritis, 95 spondyloarthritis, 75 Crohn’s disease, 43 ulcerative colitis) on TNFi either received a 4th and a 5th vaccine dose or had a SARS-CoV-2 infection after the 4th vaccine dose. (Table 1) In infection-naïve patients, a 5th BA.4/5 vaccine increased neutralizing antibody titres against all viral variants tested (WT, BA.1 and BA.4), compared to post-4th dose levels (WT: median 640, IQR (80-1280) vs median 160, IQR (80-320) p=0.0096, BA.1: 160, IQR (40-640) vs 40, IQR (20-80) p=0.0014, BA.4: 640, IQR (80-2560) vs 80, IQR (30-160) p<0.0001)). (Figure 1A). Hybrid immunity increased neutralizing antibody titres against all tested variants compared to a 4th vaccine dose (WT: median 640, IQR (320-2560), p<0.0001), BA1: median 640, IQR (320-800), p<0.0001, BA4: median 1280, IQR (640-2560) p<0.0001) and 5th vaccine dose with BA.1 (WT: median 160, IQR (80-640) p<0.0001, BA1: median 80, IQR (40-640) p<0.0001, BA4: median 120, IQR (35-640) p<0.0001). In infection naïve patients, a 5th BA.4/5 vaccine gave higher neutralizing antibody responses against BA.4 than a 5th BA.1 vaccine (p=0.006) and comparable to that after hybrid immunity (p=0.21). There was no difference in neutralizing antibody titres between patients receiving TNFi in mono- or combination therapy (WT: p=0.64, BA.1: p=0.77, BA.4/5: p=0.83). Neutralizing antibody titres against WT variant were strongly correlated to anti-spike antibody levels following all immunisations (4th monovalent (r=0.86, p<0.0001), the 5th BA.1 (r=0.72, p<0.0001), the 5th BA.4/5 (r=0.49, p<0.0001)), as well as the hybrid group (r=0.44, p<0.0001). Patients with hybrid immunity had a higher median anti-spike antibody level (23159 IU/ml, IQR (14587-44529), than did infection naïve patients receiving the 5th dose BA.1 vaccine (10095 IU/ml (IQR 5261-30.095), p=0.0009), but comparable to levels after a BA.4/5 vaccine dose (17450 IU/ml (IQR 6705-57767), p=0.16). (Figure 1B) Conclusion: Our findings highlight the effectiveness of updated, targeted vaccines as booster doses for IMID patients on TNFi, in terms of neutralizing and anti-spike antibody responses. Infection-naïve patients benefit most from updated vaccines, providing a humoral response comparable to that following SARS-CoV-2 infection.Table 1. Patient characteristics. REFERENCES: NIL. Acknowledgements: We thank the patients who have participated in the Nor-vaC study. We are grateful for the time and effort they have invested in the project. We thank the patient representatives in the study group, Kristin Isabella Kirkengen Espe and Roger Thoresen. Many people have contributed to the study design and implementation of the study at The Norwegian Institute of Public Health, Akershus University Hospital, Diakonhjemmet hospital, and Oslo University Hospital. We thank all study personnel, laboratory personnel, and other staff at the clinical departments involved. Disclosure of Interests: Hilde S. Ørbo: None declared, Taissa M. Kasahara: None declared, Asia-Sophia Wolf: None declared, Kristin Hammersbøen Bjørlykke Janssen-Cilag, Joe Sexton: None declared, Ingrid Jyssum: None declared, Anne Therese Tveter: None declared, Guri Solum: None declared, Ingrid Fadum Kjønstad: None declared, Andreas Lind: None declared, Veselka P. Dimova-Svetoslavova: None declared, Tore K. Kvien Grünenthal, Janssen, Sandoz, AbbVie, Gilead, Janssen, Novartis, Pfizer, Sandoz, UCB, AbbVie, BMS, Galapagos, Novartis, Pfizer, UCB, Jørgen Jahnsen AbbVie/Abbott, Bristol-Myers, Squibb, Galapagos, Gilead, Janssen, Pfizer, Roche, Sandoz, Takeda, AbbVie/Abbott, Pfizer, Espen A. Haavardsholm Pfizer, UCB, Novartis, Abbvie, Pfizer, Eli Lilly, Ludvig A. Munthe Incyte, Janssen, Sella Aarrestad Provan: None declared, John Torgils Vaage: None declared, Siri Mjaaland: None declared, Kristin Kaasen Jørgensen Bristol-Myers Squibb, Roche, Gunnveig Grødeland Bayer, Sanofi, ThermoFisher, Pfizer, Vitusapotek, GSK, Silje Watterdal Syversen: None declared, Guro Løvik Goll AbbVie/Abbott, Galapagos, Pfizer, UCB.Figure 1Serology results showing neutralizing antibody titers (A) and anti-spike antibody levels (B) in infection-naïve patients following a 4th monovalent and a 5th bivalent vaccine dose (BA.1 vs BA4/5), as well as in patients with hybrid immunity post-infection following a 4th vaccine dose (4th hybrid). Statistical significance is denoted by * (p<0.05), **, (p<0.01), *** (p<0.001), and **** (p<0.0001).

Background: Patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressive therapies have attenuated humoral vaccine responses and are prone to more severe infections. Assessing the persistence of cellular and humoral immunity following repeated SARS-CoV-2 vaccine doses and infection is important to evaluate the need for booster vaccine doses. Objectives: To assess the cellular and humoral responses to 4th (original) and 5th (updated BA.1 or BA.4/5) SARS-CoV-2 vaccine doses and to COVID-19 following a 4th vaccine dose (hybrid immunity) in IMID patients on tumour necrosis factor inhibitors (TNFi). Methods: The ongoing observational Nor-vaC study includes IMID patients receiving multiple SARS-CoV-2 vaccines. In the present analyses, patients using TNFi who were eligible for a 5th vaccine dose and/or undergoing COVID-19 following a 4th vaccine dose, provided serum and peripheral blood mononuclear cells (PBMCs) 2-4 weeks and 4-11 months following infection, and before, 2-4 weeks, and 6 months after their 5th vaccination. CD4 and CD8 T cell responses to SARS-CoV-2 spike, nucleocapsid and membrane peptides, and also IgG anti-spike antibodies, were analysed. T cell responses were measured by flow cytometry (≥0.01% increase in responding CD4 or CD8 cells compared to unstimulated cells). Results: Between December 17th, 2021, and June 20th, 2023, 394 IMID patients (86 rheumatoid arthritis, 72 psoriatic arthritis, 97 spondyloarthritis, 86 Crohn’s disease, 53 ulcerative colitis) on TNFi received a 4th and 5th vaccine dose, and/or had COVID-19 following a 4th vaccine dose. (Table 1). Infection induced a small increase in spike-specific CD4 T cell responses in individuals who had already received a 4th dose (median (IQR) frequencies); four vaccine doses vs. hybrid immunity, 0.068% (0.034-0.16) vs. 0.11% (0.080-0.17), p=0.048). CD4 T cell responses after hybrid immunity waned over 4-11 months (0.035% (0.026-0.072), (hybrid immunity at 2-4 weeks vs. 4-11 months, p=0.0008). CD8 T cell responses following 4th vaccine dose (0.040 % (0.010-0.14) remained stable after infection (0.054% (0.025-0.17) p=0.57), and also in the next 4-11 months (0.038% (0.013-0.17) p=0.63). (Figure 1) A 5th vaccine dose restored CD4 T cell responses to the level seen 2-4 weeks after infection (0.089% (0.046-0.15), p=0.0093) compared with levels prior to 5th vaccine dose. CD8 T cell responses to a 5th vaccine dose did not significantly differ from those post-infection (0.057% (0.016-0.21) p=0.63). After infection, 32/36 (89%) patients had nucleocapsid-specific CD4 T cell responses and 23/36 (64%) had membrane-specific CD4 T cell responses. Similarly, 30/36 (83%) and 22/36 (61%) patients had nucleocapsid- and membrane-specific CD8 T cell responses. These responses decreased over time and were not boosted by vaccination. Patients with hybrid immunity had higher IgG anti-spike antibody levels than patients receiving only 4th dose (median 23159 IU/mL (IQR 14588-44529) vs 7242 (3220-17259) p<0.001. This humoral response waned prior to the 5th dose but increased following the 5th vaccine dose, median 9109 (3603-19839) vs. 31198 (13976-51224), p<0.001). Conclusion: CD8 T cell responses after four immunisations showed no significant benefit of further boosting, suggesting long-lived cellular responses that could be clinically protective. CD4 T cell and humoral responses wane following both four vaccinations and infection but are restored by vaccine boosters, indicating that also IMID patients with hybrid immunity could benefit from a booster vaccine to maintain high levels of circulating antibodies and spike-specific T cells.Table 1. Patient characteristics REFERENCES: NIL. Acknowledgements: We thank the patients who have participated in the Nor-vaC study. We are grateful for the time and effort they have invested in the project. We thank the patient representatives in the study group, Kristin Isabella Kirkengen Espe and Roger Thoresen. Many people have contributed to the study design and implementation of the study at The Norwegian Institute of Public Health, Akershus University Hospital, Diakonhjemmet hospital, and Oslo University Hospital. We thank all study personnel, laboratory personnel, and other staff at the clinical departments involved. Disclosure of Interests: Hilde S. Ørbo: None declared, Asia-Sophia Wolf: None declared, Taissa M. Kasahara: None declared, Kristin Hammersbøen Bjørlykke Janssen-Cilag, Ingrid Jyssum: None declared, Joe Sexton: None declared, Anne Therese Tveter: None declared, Guri Solum: None declared, Ingrid Fadum Kjønstad: None declared, Ingrid E. Christensen: None declared, Tore K. Kvien Grünenthal, Janssen, Sandoz, AbbVie, Gilead, Janssen, Novartis, Pfizer, Sandoz, UCB, AbbVie, BMS, Galapagos, Novartis, Pfizer, UCB, Grete B. Kro: None declared, Jørgen Jahnsen AbbVie/Abbott, Bristol-Myers, Squibb, Galapagos, Gilead, Janssen, Pfizer, Roche, Sandoz, Takeda, AbbVie/Abbott, Pfizer, Espen A. Haavardsholm Pfizer, UCB, Novartis, Abbvie, Pfizer, Eli Lilly, Ludvig A. Munthe Incyte, Janssen, Sella Aarrestad Provan: None declared, John Torgils Vaage: None declared, Kristin Kaasen Jørgensen Bristol-Myers Squibb, Roche, Gunnveig Grødeland Bayer, Sanofi, ThermoFisher, Pfizer, Vitusapotek, GSK, Siri Mjaaland: None declared, Silje Watterdal Syversen: None declared, Guro Løvik Goll AbbVie/Abbott, Galapagos, Pfizer, UCB.Figure 1CD4 T cells and anti-spike antibody levels following a 4th vaccine dose are boosted by infection (4th dose hybrid), with subsequent waning prior to a 5th vaccine dose before increasing after a 5th dose, in contrast to stable CD8 T-cell responses.

Cold agglutinin disease (CAD) is a rare B-cell lymphoproliferative disorder of the bone marrow, manifested by autoimmune hemolytic anemia caused by binding of monoclonal IgM autoantibodies to the I antigen. Underlying genetic changes have previously been reported, but their impact on gene expression profile has been unknown. Here, we define differentially expressed genes in CAD B cells. To unravel downstream alteration in cellular pathways, gene expression by RNA sequencing was undertaken. Clonal B-cell samples from 12 CAD patients and IgM-expressing memory B cells from 4 healthy individuals were analyzed. Differential expression analysis and filtering resulted in 93 genes with significant differential expression. Top upregulated genes included SLC4A1, SPTA1, YBX3, TESC, HBD, AHSP, TRAF1, HBA2, RHAG, CA1, SPTB, IL10, UBASH3B, ALAS2, HBA1, CRYM, RGCC, KANK2, and IGHV4-34. They were upregulated at least 8-fold, while complement receptor 1 (CR1/CD35) was downregulated 11-fold in clonal CAD B cells compared to control B cells. Flow cytometry analyses further confirmed reduced CR1 (CD35) protein expression by clonal CAD IgM+ B cells compared to IgM+ memory B cells in controls. CR1 (CD35) is an important negative regulator of B-cell activation and differentiation. Therefore, reduced CR1 (CD35) expression may increase activation, proliferation, and antibody production in CAD-associated clonal B cells. Differential mRNA expression analysis was performed in clonal B-cells from CAD patients, using IgM-expressing memory B cells from healthy individuals, as controls. While several genes, including SLC4A1, SPTA1, YBX3, TESC, HBD, AHSP, TRAF1, HBA2, RHAG, CA1, SPTB, IL10, UBASH3B, ALAS2, HBA1, CRYM, RGCC, KANK2, and IGHV4-34 were found upregulated, at least 8-fold, the gene for complement receptor 1 (CR1/CD35) was found downregulated 11-fold. Importantly, flow cytometry analyses confirmed that clonal CAD IgM+ B cells had reduced CR1 protein expression, compared to IgM+ memory B cells in controls. Graphical Abstract

People who use drugs (PWUD) are at a high risk of contracting and developing severe coronavirus disease 2019 (COVID-19) and other infectious diseases due to their lifestyle, comorbidities, and the detrimental effects of opioids on cellular immunity. However, there is limited research on vaccine responses in PWUD, particularly regarding the role that T cells play in the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we show that before vaccination, PWUD did not exhibit an increased frequency of preexisting cross-reactive T cells to SARS-CoV-2 and that, despite the inhibitory effects that opioids have on T-cell immunity, standard vaccination can elicit robust polyfunctional CD4+ and CD8+ T-cell responses that were similar to those found in controls. Our findings indicate that vaccination stimulates an effective immune response in PWUD and highlight targeted vaccination as an essential public health instrument for the control of COVID-19 and other infectious diseases in this group of high-risk patients.