Immunogenicity of COVID-19 vaccines in patients with follicular lymphoma receiving frontline chemoimmunotherapy.

Immune responses to primary COVID-19 vaccination were investigated in 58 patients with follicular lymphoma (FL) as part of the PETReA trial of frontline therapy (EudraCT 2016-004010-10). COVID-19 vaccines (BNT162b2 or ChAdOx1) were administered before, during or after cytoreductive treatment comprising rituximab (depletes B cells) and either bendamustine (depletes CD4+ T cells) or cyclophosphamide-based chemotherapy. Blood samples obtained after vaccine doses 1 and 2 (V1, V2) were analysed for antibodies and T cells reactive to the SARS-CoV-2 spike protein using the Abbott Architect and interferon-gamma ELISpot assays respectively. Compared to 149 healthy controls, patients with FL exhibited lower antibody but preserved T-cell responses. Within the FL cohort, multivariable analysis identified low pre-treatment serum IgA levels and V2 administration during induction or maintenance treatment as independent determinants of lower antibody and higher T-cell responses, and bendamustine and high/intermediate FLIPI-2 score as additional determinants of a lower antibody response. Several clinical scenarios were identified where dichotomous immune responses were estimated with >95% confidence based on combinations of predictive variables. In conclusion, the immunogenicity of COVID-19 vaccines in FL patients is influenced by multiple disease- and treatment-related factors, among which B-cell depletion showed differential effects on antibody and T-cell responses.

Soluble CTLA-4 attenuates T cell activation and modulates anti-tumor immunity.

CTLA-4 is a crucial immune checkpoint receptor involved in the maintenance of immune homeostasis, tolerance, and tumor control. Antibodies targeting CTLA-4 have been promising treatments for numerous cancers, but the mechanistic basis of their anti-tumoral immune-boosting effects is poorly understood. Although the ctla4 gene also encodes an alternatively spliced soluble variant (sCTLA-4), preclinical/clinical evaluation of anti-CTLA-4-based immunotherapies have not considered the contribution of this isoform. Here, we explore the functional properties of sCTLA-4 and evaluate the efficacy of isoform-specific anti-sCTLA-4 antibody targeting in a murine cancer model. We show that expression of sCTLA-4 by tumor cells suppresses CD8+ T cells in vitro and accelerates growth and experimental metastasis of murine tumors in vivo. These effects were accompanied by modification of the immune infiltrate, notably restraining CD8+ T cells in a non-cytotoxic state. sCTLA-4 blockade with isoform-specific antibody reversed this restraint, enhancing intratumoral CD8+ T cell activation and cytolytic potential, correlating with therapeutic efficacy and tumor control. This previously unappreciated role of sCTLA-4 suggests that the biology and function of multi-gene products of immune checkpoint receptors need to be fully elucidated for improved mechanistic understanding of cancer immunotherapies.

COVID-19 outcomes in haematopoietic cell transplant recipients: A systematic review and meta-analysis.

Up-to-date information on coronavirus disease 2019 (COVID-19) outcomes and risk factors in haematopoietic cell transplantation (HCT) recipients is required to inform on decisions about cancer treatment and COVID-19 mitigation strategies. We performed a meta-analysis to address this knowledge gap. All studies with at least five patients who reported COVID-19-related deaths in HCT recipients were included. The primary outcome was COVID-19-related death. Secondary outcomes were COVID-19-related mechanical ventilation (MV) and intensive care unit (ITU) admission. The cumulative COVID-19-related death rate among HCT recipients was 21% (95% confidence interval [CI] 18%-24%), while MV and ITU admission rates were 14% (95% CI 11%-17%) and 18% (95% CI 14%-22%), respectively. Subgroup analysis showed higher death rates in patients who developed COVID-19 within 12 months of HCT (risk ratio [RR] 1.82, 95% CI 1.09-3.03), within 6 months of receiving immunosuppressant drugs (RR 2.11, 95% CI 1.38-3.20) or in the context of active graft-versus-host disease (RR 2.38, 95% CI 1.10-5.16). Our findings support the idea that HCT should remain an integral part of cancer treatment during the COVID-19 pandemic but also highlight the need to prioritise preventative measures in those patients who are at increased risk of adverse COVID-19 outcomes.

Autologous Hematopoietic Stem Cell Transplantation for Behçet's Disease: A Retrospective Survey of Patients Treated in Europe, on Behalf of the Autoimmune Diseases Working Party of the European Society for Blood and Marrow Transplantation.

Background: Behçet's Disease (BD) is an autoimmune disease mostly presenting with recurrent oral and genital aphthosis, and uveitis. Patients are rarely refractory to immunosuppressive treatments. Autologous hematopoietic stem cell transplantation (aHSCT) is a standard of care in other autoimmune diseases. Some patients with BD have been treated with aHSCT based on compassionate use. Objectives: Evaluate the outcome of aHSCT in adult patients with BD treated in member centers of the European Society for Blood and Marrow Transplantation (EBMT). Methods: Adults who received aHSCT primarily for BD were identified retrospectively in the EBMT registry and/or in published literature. Data were extracted from either medical records of the patient or from publications. Results: Eight out of 9 cases reported to the registry and extracted data of 2 further patients from literature were analyzed. Four were female, median age at onset of BD was 24y (range 9-50). Median age at aHSCT was 32y (27-51). Patients had received median 4 (2-11) previous lines of therapy (89% corticosteroids, 50% methotrexate, anti-TNFα therapy or cyclophosphamide). All patients had active disease before mobilization. Conditioning regimen was heterogeneous. Median follow-up was 48 months (range 6-240). No treatment-related mortality was reported. This procedure induced complete remission (CR) in 80%, partial remission in 10% and lack of response in 10% of the patients. Relapse rate was 30% (2 relapses in patients in CR and 1 relapse in the patient in PR) with panuveitis (n=1), aphthosis (n=2) and arthralgia (n=1). Six patients were in CR. No late complications were reported. Conclusion: aHSCT has an acceptable safety profile and represents a feasible and relatively effective procedure in severe and conventional treatment-resistant cases of BD and has the potential to stabilize BD in patients with life-threatening involvements.