Immune cells critically influence pituitary neuroendocrine tumor (PitNET) progression and therapeutic responses. However, their composition and functional dynamics remain unclear. This study aimed to delineate the immune heterogeneity and intercellular communication networks within PitNETs. This study conducted single-cell RNA sequencing (scRNA-seq) on 22 fresh PitNET samples obtained from surgical patients at Beijing Tiantan Hospital between September 2023 and January 2024, with classification based on the expression of key transcription factors: pituitary-specific transcription factor 1 (PIT1), steroidogenic factor 1 (SF1), and T-box transcription factor 19 (TPIT). Following cell type identification, cell-cell communication analysis revealed specific intercellular interactions, which were validated by multiplex immunohistochemistry (mIHC), flow cytometry, and in vitro co-culture assays. The scRNA-seq analysis revealed significant cellular heterogeneity and a lineage-specific immune landscape, including cancer-associated fibroblasts (CAFs), neutrophils, T cells, natural killer cells, and myeloid cells. Specifically, CAF subset distribution was highly lineage-dependent. Collagen-expressing CAF3 was significantly enriched in the PIT1 lineage compared to both TPIT and SF1 lineages. In contrast, inflammatory CAF5 was predominantly found in the TPIT lineage relative to the PIT1 and SF1 lineages. Furthermore, CD4+ regulatory T (Treg) and T follicular helper (Tfh) cells were significantly enriched in the PIT1 lineage relative to the TPIT and SF1 lineages, as validated by both flow cytometry and mIHC data. Cellular communication analysis revealed notable interactions between Treg/Tfh cells and macrophages/microglia that were mediated by the cytotoxic T-lymphocyte-associated protein 4 (CTLA4)-CD86 pathway. Subsequent mIHC assays confirmed spatial colocalization of Treg cells with macrophages/microglia. Complementing these findings, in vitro co-culture assays demonstrated functional CTLA4-CD86 signaling specifically between Treg cells and macrophages, providing deeper insights into the complex cellular crosstalk within the PitNET tumor microenvironment (TME). The three major PitNET lineages exhibited distinct immune cell frequencies, with the PIT1 lineage notably enriched in Treg and Tfh cells, as well as collagen-producing CAF3. Furthermore, a novel immunosuppressive interaction between Treg cells and macrophages, mediated by the CTLA4-CD86 pathway, was identified, suggesting its potential regulatory role within the TME.

Sepsis is a global health challenge associated with high morbidity and mortality rates. Early diagnosis and treatment are challenging because of the limited understanding of its underlying mechanisms. This study aimed to identify effective biomarkers for diagnosing and treating sepsis through an integrated multi-method approach. Publicly available single-cell RNA sequencing (scRNA-seq) and bulk RNA-seq datasets were analyzed for naive CD4+ T cell-specific genes. Based on these hub genes, Mendelian randomization (MR) analysis, followed by the MR-Bayesian model averaging (MR-BMA) algorithm, was implemented to explore the causality between these genes and sepsis. In addition, single-cell-type expression analysis, cell-cell communication detection, metabonomic evaluation, clinical samples, and both in vivo and in vitro studies were conducted to unveil the underlying mechanisms of potential therapeutic targets. scRNA-seq revealed significant depletion of naive CD4+ T cells in sepsis, identifying 33 key genes. Both MR and MR-BMA analyses confirmed that elevated proportion of naive CD4+ T cell in total CD4+ T cells (naive CD4+ T cell % CD4+ T cell) were related to sepsis occurrence (odds ratio [OR] = 0.90, 95% confidence interval [CI], 0.83-0.97, P = 0.007) and 28-day mortality associated with sepsis (OR = 0.75, 95% CI, 0.64-0.88, P <0.001). Notably, among the 33 hub genes, PC-esterase domain containing 1B (PCED1B) exhibited a strong causal association with 28-day mortality in patients with sepsis (OR = 0.64, 95% CI, 0.51-0.81, P <0.001), which was further validated by bulk RNA-seq analysis. PCED1B mediated the impact of proportion of naive CD4+ T cell in CD4+ T cell on sepsis-related mortality. In addition, clinical samples and both in vivo and in vitro experiments validated the elevated expression of PCED1B in naive CD4+ T cells derived from sepsis patients and mice. Mechanistic investigations revealed PCED1B+ CD4+ T cells may interact with monocytes/dendritic cells through the MIF-(CD74+CD44) axis, concurrently engaging with B cells/plasmablasts through the MIF-(CD74+CXCR4) axis, thereby regulating multiple metabolic alterations in sepsis. The interplay between PCED1B and naive CD4+ T cells, as revealed by this study, is instrumental in developing immunotherapeutic strategies for sepsis.

Data on antiviral treatment for infants with chronic hepatitis B (CHB) are limited. This study is aimed to investigate whether and how antiviral treatment can achieve a functional cure in infants with CHB. This real-world study enrolled 21 infants (9 boys and 12 girls) with active hepatitis B e antigen (HBeAg)-positive CHB from the Fifth Medical Center of Chinese PLA General Hospital, who were perinatally infected with hepatitis B virus (HBV) by mother-to-child transmission. The median baseline age was 9 months. Twenty-one cases initially received Lamivudine (LAM) monotherapy, and interferon-α (IFN-α) treatment was added when they were more than 12 months old. The virological responses, functional cure, and treatment safety were analyzed for 36 months (treatment plus follow-up visit duration). All 21 infants with CHB (baseline median HBV DNA was 7.75 log10 IU/mL) had full viral suppression on antiviral treatment, and the median time taken for undetectable HBV DNA was 6 months (range: 1-19 months). Correspondingly, the median time taken for HBeAg seroconversion was 7 months (range: 3-18 months) for 20 infants, and one case did not obtain HBeAg seroconversion; 19 of the 21 infants achieved a functional cure through a median time of 9 months (range: 4-27 months) since baseline. Two infants did not achieve a functional cure at the 36-month endpoint, but they achieved undetectable HBV DNA, and one of them had HBeAg seroconversion. Flu-like symptoms associated with IFN-α treatment were the common side effects; however, no serious adverse events were observed. Our findings indicate that under 1-year-old infants with active CHB can achieve a significantly high probability of a functional cure when they receive a definite duration of antiviral treatment using LAM add-on IFN-α therapy.

The cardiovascular-kidney-metabolic (CKM) syndrome is highly prevalent globally. However, the associations between the CKM syndrome and its various components and all-cause and cause-specific mortality are not well understood. This study aims to clarify these mortality associations and inform preventive strategies. The China Health Evaluation and Risk Reduction through Nationwide Teamwork was a nationwide and population-based project, which was performed in 353 counties/districts across 31 provincial-level administrative divisions in Chinese mainland. A total of 764,856 eligible residents aged ≥35 years from this cohort were included in the study. CKM was classified into stages 0-4 and further sub-grouped stages 2-4 by the presence of chronic kidney disease (CKD) and CKD risk stratification. CKM stage 2 was further divided into six groups in descending order of clinical risk priority. The main outcomes were all-cause and cause-specific mortality. Cox proportional hazards models were performed to evaluate the associations of CKM stages and components with mortality, incorporating competing risks models to account for competing events. We found significant positive associations between CKM stages and mortality risk, particularly for cardiovascular mortality with adjusted hazard ratios and 95% confidence intervals of 2.62 (2.10-3.27), 4.04 (3.22-5.07), and 5.64 (4.51-7.05) for stages 2, 3, and 4, respectively. In comparison of participants with CKD with those without CKD at each CKM stage, CKD was associated with an increased risk of all-cause mortality by 64.29%, 68.62%, and 74.89%, and an increased risk of cardiovascular mortality by 72.58%, 71.55%, and 71.95% for CKM stages 2, 3, and 4, respectively. Notably, even moderate-risk CKD was associated with an increased risk of mortality. Among the various components at CKM stage 2, CKD (both high- and moderate-risk) was the most significant risk factor for mortality, with high-risk CKD showing a higher risk (hazard ratio [95% confidence interval]: 2.83 [2.36-3.39]) than moderate-risk CKD (hazard ratio [95% confidence interval]: 2.16 [1.89-2.47]), followed by the coexistence of diabetes and hypertension (hazard ratio [95% confidence interval]: 1.87 [1.65-2.12]) (all P <0.05). The risk of mortality, primarily by cardiovascular disease, increases with advancing stages of CKM. Sub-staging CKM syndrome by stratifying patients according to the presence and severity of CKD and metabolic risk factors can improve the accuracy of evaluating the mortality risk. Consistent monitoring and early interventions aimed at maintaining renal function may considerably reduce the risk of mortality.