Immunosuppressive tumor microenvironment contributes to tumor progression in diffuse large B-cell lymphoma upon anti-CD19 chimeric antigen receptor T therapy / 医学前沿

Anti-CD19 chimeric antigen receptor (CAR)-T cell therapy has achieved 40%-50% long-term complete response in relapsed or refractory diffuse large B-cell lymphoma (DLBCL) patients. However, the underlying mechanism of alterations in the tumor microenvironments resulting in CAR-T cell therapy failure needs further investigation. A multi-center phase I/II trial of anti-CD19 CD28z CAR-T (FKC876, ChiCTR1800019661) was conducted. Among 22 evaluable DLBCL patients, seven achieved complete remission, 10 experienced partial remissions, while four had stable disease by day 29. Single-cell RNA sequencing results were obtained from core needle biopsy tumor samples collected from long-term complete remission and early-progressed patients, and compared at different stages of treatment. M2-subtype macrophages were significantly involved in both in vivo and in vitro anti-tumor functions of CAR-T cells, leading to CAR-T cell therapy failure and disease progression in DLBCL. Immunosuppressive tumor microenvironments persisted before CAR-T cell therapy, during both cell expansion and disease progression, which could not be altered by infiltrating CAR-T cells. Aberrant metabolism profile of M2-subtype macrophages and those of dysfunctional T cells also contributed to the immunosuppressive tumor microenvironments. Thus, our findings provided a clinical rationale for targeting tumor microenvironments and reprogramming immune cell metabolism as effective therapeutic strategies to prevent lymphoma relapse in future designs of CAR-T cell therapy.

Early assessment of the safety and immunogenicity of a third dose (booster) of COVID-19 immunization in Chinese adults / 医学前沿

Inducing durable and effective immunity against severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) via vaccination is essential to combat the current pandemic of coronavirus disease 2019 (COVID-19). It has been noticed that the strength of anti-COVID-19 vaccination-induced immunity fades over time, which calls for an additional vaccination regime, as known as booster immunization, to restore immunity among previously vaccinated populations. Here we report a pilot open-label trial of a third dose of BBIBP-CorV, an inactivated SARS-CoV-2 vaccine (Vero cell), on 136 participants aged between 18 to 63 years. Safety and immunogenicity in terms of neutralizing antibody titers and cytokine/chemokine responses were analyzed as the main endpoint until day 28. While systemic reactogenicity was either absent or mild, SARS-CoV-2-specific neutralizing antibody titers rapidly arose in all participants within 4 weeks, surpassing the peak antibody titers elicited by the initial two-dose immunization regime. Broad increases of cellular immunity-associated cytokines and chemokines were also detected in the majority of participants after the third vaccination. Furthermore, in an exploratory study, a newly developed recombinant protein vaccine, NVSI-06-08 (CHO Cells), was found to be safe and even more effective than BBIBP-CorV in eliciting humoral immune responses in BBIBP-CorV-primed individuals. Together, these results indicate that a third immunization schedule with either homologous or heterologous vaccine showed favorable safety profiles and restored potent SARS-CoV-2-specific immunity, providing support for further trials of booster vaccination in larger populations.