Kinetics of cellular and humoral immunogenicity and effectiveness of SARS-CoV-2 booster vaccination in hematologic neoplasms.

Data on the effect of booster SARS-CoV-2 vaccination are mainly focused on humoral immunogenicity, while the kinetics of vaccine-induced cellular response and its correlation with effectiveness in hematologic patients are less explored. Our aim was to evaluate the longitudinal cellular and humoral immunogenicity induced by two and three doses of the mRNA-1273 SARS-CoV-2 vaccine in 270 patients with hematologic malignancies, and its relationship with the severity of breakthrough SARS-CoV-2 infection. Results indicate that at 23 weeks after the second dose, the seroconversion rate declined from 68.5% to 59.3%, with a reduction in median anti-S titers from 1577 to 456 BAU/mL, mainly in patients over 65 years of age or chronic lymphocytic leukemia (CLL) patients undergoing active therapy. Cellular immunogenicity, however, remained positive in 84.4% of cases. A third vaccine dose seroconverted 42.7% (41/96) and triggered cellular response in 36.7% (11/30) of previously negative patients. Notably, only 7.2% (15/209) of patients failed to develop both humoral and cellular response. Active therapy, anti-CD20 antibodies, lymphopenia, hypogammaglobulinemia, and low CD19+ cell count were associated with poor humoral response, while active disease, GvHD immunosuppressive therapy, lymphopenia, and low CD3+ , CD4+ , CD56+ cell count determined an impaired cellular response. After 13.8 months of follow-up, the incidence of SARS-CoV-2 infection was 24.8% (67/270), including 6 (9%) severe/critical cases associated with a weaker cellular (median interferon gamma (IFN-γ) 0.19 vs. 0.35 IU/mL) and humoral response (median anti-S titer <4.81 vs. 788 BAU/mL) than asymptomatic/mild cases. In conclusion, SARS-CoV-2 booster vaccination improves humoral response and COVID-19 severity is associated with impaired vaccine-induced immunogenicity.

Cellular and humoral immunogenicity of the mRNA-1273 SARS-CoV-2 vaccine in patients with hematologic malignancies.

Recent studies have shown a suboptimal humoral response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) messenger RNA (mRNA) vaccines in patients diagnosed with hematologic malignancies; however, data about cellular immunogenicity are scarce. The aim of this study was to evaluate both the humoral and cellular immunogenicity 1 month after the second dose of the mRNA-1273 vaccine. Antibody titers were measured by using the Elecsys and LIAISON anti-SARS-CoV-2 S assays, and T-cell response was assessed by using interferon-γ release immunoassay technology. Overall, 76.3% (184 of 241) of patients developed humoral immunity, and the cellular response rate was 79% (184 of 233). Hypogammaglobulinemia, lymphopenia, active hematologic treatment, and anti-CD20 therapy during the previous 6 months were associated with an inferior humoral response. Conversely, age >65 years, active disease, lymphopenia, and immunosuppressive treatment of graft-versus-host disease (GVHD) were associated with an impaired cellular response. A significant dissociation between the humoral and cellular responses was observed in patients treated with anti-CD20 therapy (the humoral response was 17.5%, whereas the cellular response was 71.1%). In these patients, B-cell aplasia was confirmed while T-cell counts were preserved. In contrast, humoral response was observed in 77.3% of patients undergoing immunosuppressive treatment of GVHD, whereas only 52.4% had a cellular response. The cellular and humoral responses to the SARS-CoV-2 mRNA-1273 vaccine in patients with hematologic malignancies are highly influenced by the presence of treatments such as anti-CD20 therapy and immunosuppressive agents. This observation has implications for the further management of these patients.

Repolarization of tumor infiltrating macrophages and increased survival in mouse primary CNS lymphomas after XPO1 and BTK inhibition.

BACKGROUND: Patients diagnosed with primary central nervous system lymphoma (PCNSL) often face dismal outcomes due to the limited availability of therapeutic options. PCNSL cells frequently have deregulated B-cell receptor (BCR) signaling, but clinical responses to its inhibition using ibrutinib have been brief. In this regard, blocking nuclear export by using selinexor, which covalently binds to XPO1, can also inhibit BCR signaling. Selinexor crosses the blood-brain barrier and was recently shown to have clinical activity in a patient with refractory diffuse large B-cell lymphoma in the CNS. We studied selinexor alone or in combination with ibrutinib in pre-clinical mouse models of PCNSL. METHODS: Orthotopic xenograft models were established by injecting lymphoma cells into the brain parenchyma of athymic mice. Tumor growth was monitored by bioluminescence. Malignant cells and macrophages were studied by immunohistochemistry and flow cytometry. RESULTS: Selinexor blocked tumor growth and prolonged survival in a bioluminescent mouse model, while its combination with ibrutinib further increased survival. CNS lymphoma in mice was infiltrated by tumor-promoting M2-like macrophages expressing PD-1 and SIRPα. Interestingly, treatment with selinexor and ibrutinib favored an anti-tumoral immune response by shifting polarization toward inflammatory M1-like and diminishing PD-1 and SIRPα expression in the remaining tumor-promoting M2-like macrophages. CONCLUSIONS: These data highlight the pathogenic role of the innate immune microenvironment in PCNSL and provide pre-clinical evidence for the development of selinexor and ibrutinib as a new promising therapeutic option with cytotoxic and immunomodulatory potential.