Granzyme B-Producing B Cells Function as a Feedback Loop for T Helper Cells in Liver Transplant Recipients with Acute Rejection

Effect of Immunosuppressive Regimens on Metabolic Dysfunction-associated Fatty Liver Disease Following Liver Transplantation

Background

Metabolic dysfunction-associated fatty liver disease has been linked to negative outcomes in patients with end-stage liver disease following liver transplantation. However, the influence of immunosuppressive regimens on it has not been explored.

Methods

A retrospective analysis was conducted using the preoperative and postoperative data from patients with end-stage liver disease. The study compared three different groups: tacrolimus-based group, sirolimus-based group, and combined tacrolimus- and sirolimus-based regimens. Binary logistic regression analysis was employed to identify risk factors for metabolic dysfunction-associated fatty liver disease.

Results

A total of 171 patients participated in the study, consisting of 127 males and 44 females, with a mean age of 49.6 years. The prevalence of posttransplant metabolic dysfunction-associated fatty liver disease was 29.23%. Among the three groups, there were 111 liver transplant recipients in the tacrolimus-based group, 28 in the sirolimus-based group, and 32 in the combination group. A statistically significant difference was observed in the incidence of metabolic dysfunction-associated fatty liver disease (P < 0.05), whereas the other preoperative and postoperative parameters showed no significant differences. Multivariate analysis revealed that a low-calorie diet (95% confidence intervals: 0.15-0.90, P = 0.021) and a combination of tacrolimus- and sirolimus-based immunosuppressive regimen (95% confidence intervals: 1.01-2.77, P = 0.046) were associated with lower risk of posttransplant metabolic dysfunction-associated fatty liver disease.

Conclusions

Our study indicates that implementing a low-calorie diet and utilizing a combination of tacrolimus- and sirolimus-based immunosuppressive regimen can effectively lower the risk of posttransplant metabolic dysfunction-associated fatty liver disease following liver transplantation.

Germinal center B-cell subgroups in the tumor microenvironment cannot be overlooked: Their involvement in prognosis, immunotherapy response, and treatment resistance in head and neck squamous carcinoma

Background

More than 60 % of patients with head and neck squamous carcinoma (HNSCC) are diagnosed at advanced stages and miss radical treatment. This has prompted the need to find new biomarkers to achieve early diagnosis and predict early recurrence and metastasis of tumors.

Methods

Single-cell RNA sequencing (scRNA-seq) data from HNSCC tissues and peripheral blood samples were obtained through the Gene Expression Omnibus (GEO) database (GSE164690) to characterize the B-cell subgroups, differentiation trajectories, and intercellular communication networks in HNSCC and to construct a prognostic model of the associated risks. In addition, this study analyzed the differences in clinical features, immune cell infiltration, functional enrichment, tumor mutational burden (TMB), and drug sensitivity between the high- and low-risk groups.

Results

Using scRNA-seq of HNSCC, we classified B and plasma cells into a total of four subgroups: naive B cells (NBs), germinal center B cells (GCBs), memory B cells (MBs), and plasma cells (PCs). Pseudotemporal trajectory analysis revealed that NBs and GCBs were at the early stage of B cell differentiation, while MBs and PCs were at the end. Cellular communication revealed that GCBs acted on tumor cells through the CD99 and SEMA4 signaling pathways. The independent prognostic value, immune cell infiltration, TMB and drug sensitivity assays were validated for the MEF2B+ GCB score groups.

Conclusions

We identified GCBs as B cell-specific prognostic biomarkers for the first time. The MEF2B+ GCB score fills the research gap in the genetic prognostic prediction model of HNSCC and is expected to provide a theoretical basis for finding new therapeutic targets for HNSCC.

Impact of the diagnosis of metabolic dysfunction-associated fatty liver disease and non-alcoholic fatty liver disease in patients undergoing liver transplantation for hepatocellular carcinoma

Purpose

Whether the diagnosis of non-alcoholic fatty liver disease or metabolic dysfunction-associated fatty disease has a different impact on liver transplant recipients with hepatocellular carcinoma is not yet clear.

Methods

Data from a two-center retrospective cohort study were collected to compare and investigate the differences between non-alcoholic fatty liver disease and metabolic dysfunction-associated fatty liver disease in clinicopathologic parameters and prognosis among liver transplant recipients with hepatocellular carcinoma.

Results

A total of 268 liver transplant recipients with hepatocellular carcinoma were included. The prevalence among pre- and post-transplant metabolic dysfunction-associated fatty liver disease was 10.82% and 30.22%, while for non-alcoholic fatty liver disease, it was 7.09% and 26.87%, respectively. The clinicopathological parameters were similar between the two pre-transplant groups. In contrast, the post-transplant group with metabolic dysfunction-associated fatty liver disease exhibited a higher prevalence of diabetes mellitus and a greater body mass index. However, the other parameters were similar between the two post-transplant groups (p > 0.05). Factors such as the largest tumor size > 4 cm, microvascular invasion, lack of tumor capsule, post-transplant metabolic dysfunction-associated fatty liver disease, and decreased post-transplant lymphocyte percentage were related to an increased risk of recurrence.

Conclusion

In patients undergone liver transplantation for hepatocellular carcinoma, the diagnosis of metabolic dysfunction-associated fatty disease is more strongly associated with metabolic abnormalities than the diagnosis of non-alcoholic fatty liver disease and is an independent predictor of hepatocellular carcinoma recurrence.

Prediction of Acute Cardiac Rejection Based on Gene Expression Profiles

Acute cardiac rejection remains a significant challenge in the post-transplant period, necessitating meticulous monitoring and timely intervention to prevent graft failure. Thus, the goal of the present study was to identify novel biomarkers involved in acute cardiac rejection, paving the way for personalized diagnostic, preventive, and treatment strategies. A total of 809 differentially expressed genes were identified in the GSE150059 dataset. We intersected genes selected by analysis of variance, recursive feature elimination, least absolute shrinkage and selection operator, and random forest classifier to identify the most relevant genes involved in acute cardiac rejection. Thus, HCP5, KLRD1, GZMB, PLA1A, GNLY, and KLRB1 were used to train eight machine learning models: random forest, logistic regression, decision trees, support vector machines, gradient boosting machines, K-nearest neighbors, XGBoost, and neural networks. Models were trained, tested, and validated on the GSE150059 dataset (MMDx-based diagnosis of rejection). Eight algorithms achieved great performance in predicting acute cardiac rejection. However, all machine learning models demonstrated poor performance in two external validation sets that had rejection diagnosis based on histology: merged GSE2596 and GSE4470 dataset and GSE9377 dataset, thus highlighting differences between these two methods. According to SHAP and LIME, KLRD1 and HCP5 were the most impactful genes.

Granzyme B+ B cells detected by single-cell sequencing are associated with prognosis in patients with intrahepatic cholangiocarcinoma following liver transplantation

B cells possess anti-tumor functions mediated by granzyme B, in addition to their role in antigen presentation and antibody production. However, the variations in granzyme B+ B cells between tumor and non-tumor tissues have been largely unexplored. Therefore, we integrated 25 samples from the Gene Expression Omnibus database and analyzed the tumor immune microenvironment. The findings uncovered significant inter- and intra-tumoral heterogeneity. Notably, single-cell data showed higher proportions of granzyme B+ B cells in tumor samples compared to control samples, and these levels were positively associated with disease-free survival. The elevated levels of granzyme B+ B cells in tumor samples resulted from tumor cell chemotaxis through the MIF- (CD74 + CXCR4) signaling pathway. Furthermore, the anti-tumor function of granzyme B+ B cells in tumor samples was adversely affected, potentially providing an explanation for tumor progression. These findings regarding granzyme B+ B cells were further validated in an independent clinic cohort of 40 liver transplant recipients with intrahepatic cholangiocarcinoma. Our study unveils an interaction between granzyme B+ B cells and intrahepatic cholangiocarcinoma, opening up potential avenues for the development of novel therapeutic strategies against this disease.

Impact of metabolic dysfunction-associated fatty liver disease on liver transplant recipients with hepatitis B virus-related hepatocellular carcinoma

BACKGROUND

Metabolic dysfunction-associated fatty liver disease was proposed by international consensus to redefine the metabolic abnormal condition. However, its impact on liver transplant recipients with hepatitis B virus-related hepatocellular carcinoma has not been explored.

METHODS

A two-center retrospective cohort study on liver transplant recipients with hepatitis B virus-related hepatocellular carcinoma was performed to analyze the impact of metabolic dysfunction-associated fatty liver disease on the clinicopathologic parameters and prognosis.

RESULTS

There were 201 liver transplant recipients enrolled from two hospitals in our study. The pre- and post-transplant prevalences of metabolic dysfunction-associated fatty liver disease were 9.95% and 28.86%, respectively. The clinicopathological parameters revealed a similarity between patients with and without pre-transplant metabolic dysfunction-associated fatty liver disease. In contrast, the group with post-transplant metabolic dysfunction-associated fatty liver disease was linked with older age, a higher hepatitis recurrence rate and incidence of cardiovascular disease, usage of calcineurin inhibitors, a greater body mass index and waist circumference, lower albumin and high-density lipoprotein cholesterol levels, and poorer tumor-free survival and overall survival. The multivariate analysis showed the largest tumor size >4 cm (95% confidence intervals: 0.06~0.63, p = 0.006), microvascular invasion (95% confidence intervals: 1.61~14.92, p = 0.005), post-transplant metabolic dysfunction-associated fatty liver disease (95% confidence intervals: 1.40~10.60, p = 0.009), and calcineurin inhibitors-based regimen (95% confidence intervals: 0.33~0.96, p = 0.036) were the independent risk factors for recurrent hepatocellular carcinoma.

CONCLUSIONS

Our study suggests that post-transplant metabolic dysfunction-associated fatty liver disease is more closely to metabolic abnormalities and that it can help identify liver transplant recipients at high risk of recurrent hepatocellular carcinoma.

Impaired regulatory function of granzyme B-producing B cells against T cell inflammatory responses in lupus mice

OBJECTIVE

Recently, a new subtype of granzyme B (GrB)-producing Breg cells has been identified, which was proven to be involved in autoimmune disease. Our recent report demonstrated that GrB-producing Breg cells were correlated with clinical and immunological features of SLE. However, the effect of GrB-producing Breg cells in lupus mice is unclear.

METHODS

GrB expression in naïve and lupus mouse B cells was analysed using flow cytometry, PCR, ELISA and ELISpot assays. To study the role of GrB-producing B cells in a lupus model, GrB knockout (KO) and wild-type (WT) mice were intraperitoneally injected with monoclonal cells from the mutant mouse strain B6.C-H-2bm12 (bm12) for 2 weeks. In addition, the function of GrB-producing Breg cells in naïve and lupus mice was further explored using in vitro B cells-CD4⁺CD25^- T cell co-culture assays with GrB blockade/KO of B cells.

RESULTS

B cells from the spleens of WT C57BL/6 (B6) mice could express and secret GrB (p<0.001). GrB-producing Breg cells from WT mice showed their regulatory functions on CD4⁺CD25^- T cell. While the frequency of GrB-producing Breg cells was significantly decreased (p=0.001) in lupus mice (p<0.001). Moreover, GrB-producing Breg cells in lupus mice failed to suppress T cell-mediated proinflammatory responses, partially due to the impaired capacity of downregulating the T cell receptor-zeta chain and inducing CD4⁺CD25^- T cell apoptosis.

CONCLUSION

This study further revealed the function and mechanism of GrB-producing Breg cells in regulating T cell homeostasis in lupus mice and highlighted GrB-producing Breg cells as a therapeutic target in SLE.

The Model for End-Stage Liver Disease Score and the Follow-Up Period Can Cause the Shift of Circulating Lymphocyte Subsets in Liver Transplant Recipients

Little is known about the shift of lymphocytes under the condition of the model for end-stage liver disease score and the follow-up period. Then, we detected the peripheral blood from liver transplant recipients by flow cytometry and compared the results. The model for end-stage liver disease score affected the percentages of T-cell subsets and B cells during the short-term follow-up period, but failed to influence the lymphocyte subsets during the long-term follow-up period. In contrast, the follow-up period not only affected the absolute counts of T-cell subsets and natural killer (NK) cells in patients with the low model for end-stage liver disease scores, but also influenced the percentages and absolute counts of T-cell subsets in patients with the high model for end-stage liver disease scores. In the two-way ANOVA, we further revealed that the model for end-stage liver disease score was associated with the percentages of T cells and CD4⁺ T cells and the absolute numbers of T-cell subsets and B cells, while the follow-up period was associated with the percentages of T-cell subsets and the absolute numbers of lymphocyte subsets. Therefore, patients with either the low model for end-stage liver disease scores or the long-term follow-up period are in a relatively activated immune condition.

Significance of intratumoral infiltration of B cells in cancer immunotherapy: From a single cell perspective

Immunotherapy for cancer has provided new treatment approaches for malignant tumors, but there are low rates of response and high rates of resistance. The most recent sequencing method which is called single-cell RNA sequencing(scRNA-seq) determines the transcriptome at the single cell level, which allows high-resolution dynamic monitoring of the tumor microenvironment (TME) during immunotherapy. As an important part of humoral immunity, tumor-infiltrated B cells have been reported to have distinct functions in anti-tumor immunity, which are characterized by their RNA transcriptome, membrane surface receptors, and immunoglobulin secretion, suggesting great immunotherapeutic effects. On the basis of the important roles of B cells in immunotherapy reported in recent publications, we discuss the tumor-infiltrated B cells' subpopulations, differentiation trajectory, and interactions with other cells in the TME in this review, hoping to illustrate its significance in potential clinical application as biomarkers and therapeutic targets.