Phase I study of a non-S2P SARS-CoV-2 mRNA vaccine LVRNA009 in Chinese adults.

BACKGROUND: COVID-19 caused by SARS-CoV-2 is a great threat to public health. We present the safety and immunogenicity data from a phase I trial in China of an mRNA vaccine (LVRNA009). METHODS: In the single-centre, double-blind, placebo-controlled and dose-escalation study, 72 healthy unvaccinated adults aged 18-59 years were randomized (3:1) to receive LVRNA009 with one of three vaccine dosage (25, 50 and 100 µg) or placebo, to evaluate for the safety, tolerability and immunogenicity of LVRNA009. RESULTS: All these participants received two injections 28 days apart. No adverse events higher than grade 2 were reported during the study. A total of 30 participants (42 %) reported solicited adverse reactions during the first 14 days after vaccinations. Of the events reported, fever (n = 11, 15 %) was the most common systemic adverse reaction, and pain at the injection site (n = 17, 24 %) was the most frequent solicited local adverse reaction. Anti-S-protein IgG and neutralising antibodies were observed to have been induced 14 days after the first dose, significantly increased 7 days after the second dose, and remained at a high level 28 days after the second dose. Specific T-cell responses peaked 7 days and persisted 28 days after second vaccination. CONCLUSION: LVRNA009 has demonstrated promising results in safety and tolerability at all three dose levels among Chinese adults. LVRNA009 at three dose levels could rapidly induce strong humoral and cellular immune responses, including binding and neutralising antibody production and IFN- γ secretion, which showed good immunogenicity. CLINICAL TRIAL REGISTRATION NUMBER: Clinicaltrials.gov NCT05364047; Chictr.org.cn ChiCTR2100049349.

Elevated levels of IL-17A and IL-35 in plasma and bronchoalveolar lavage fluid are associated with checkpoint inhibitor pneumonitis in patients with non-small cell lung cancer.

Advances in the immunology have identified that interleukin (IL)-17 and IL-35 are cytokines with diverse functions, serving important roles in autoimmune diseases and chronic inflammation. Checkpoint inhibitor pneumonitis (CIP) is focal or diffuse lung inflammation induced by immune checkpoint inhibitors and the underlying pathogenesis has not been fully explored. The aim of the present study was to investigate the roles of IL-17A and IL-35, and the correlation between their levels and different T cell subsets in CIP. The levels of IL-17A and IL-35 in peripheral blood and bronchoalveolar lavage fluid (BALF) were measured in patients with non-small cell lung cancer (NSCLC) with CIP, and the corresponding controls. The percentages of helper T lymphocyte (Th)1, Th2 and Th17 cells, and regulatory T cells (Tregs) in the peripheral blood were synchronically detected. Serum levels of IL-17A and IL-35 were significantly increased at the time of CIP diagnosis compared with the baseline, and significantly decreased upon clinical recovery or improvement. IL-17A and IL-35 were also increased in the BALF during the development of CIP compared with the baseline. Serum levels of IL-17A were positively correlated with the percentages of Th1 and Th17 cells as well as the ratio of Th17 to Tregs, but negatively associated with the frequency of Tregs in CIP. Serum levels of IL-35 were positively correlated with the percentages of Th1 and Tregs, and with the ratio of Th1 to Th2 cells in CIP. A higher frequency of Th1 and Th17 cells, as well as higher ratios of Th17 to Tregs and Th1 to Th2 cells were detected upon development of CIP comparing with the baseline. These data suggested that the activation of Th1 and Th17 cells, as well as Treg inhibition contributed to the imbalanced ratios of Th1 to Th2 and Th17 to Tregs, which resulted in increased secretion of IL-17A and IL-35 in the plasma and BALF; this may present a valuable index to monitor the development and severity of CIP in patients with NSCLC receiving immunotherapy.