Chronic kidney disease(CKD)is a chronic renal structural and functional disorder caused by multiple causes(history of kidney injury>3 months),with complex etiology and high inci-dence,which will eventually lead to end-stage re-nal disease(ESRD).Common chronic kidney diseas-es include diabetic nephropathy,polycystic ne-phropathy,nephrogenic diabetes insipidus and re-nal fibrosis.At present,there is still a lack of effec-tive specific treatment for chronic kidney disease.The Apelin system is an endogenous physiological regulator.Studies have shown that Apelin is in-volved in the occurrence and development of the above diseases mainly through the regulation of kidney body fluids and blood vessels,and the regu-lation of kidney glucose and lipid metabolism and immunity.This article aims to review the role of Apelin in chronic kidney diseases in recent years,and provide ideas for the treatment and drug de-velopment of kidney diseases with Apelin as a new target.

Chronic kidney disease(CKD)is a chronic renal structural and functional disorder caused by multiple causes(history of kidney injury>3 months),with complex etiology and high inci-dence,which will eventually lead to end-stage re-nal disease(ESRD).Common chronic kidney diseas-es include diabetic nephropathy,polycystic ne-phropathy,nephrogenic diabetes insipidus and re-nal fibrosis.At present,there is still a lack of effec-tive specific treatment for chronic kidney disease.The Apelin system is an endogenous physiological regulator.Studies have shown that Apelin is in-volved in the occurrence and development of the above diseases mainly through the regulation of kidney body fluids and blood vessels,and the regu-lation of kidney glucose and lipid metabolism and immunity.This article aims to review the role of Apelin in chronic kidney diseases in recent years,and provide ideas for the treatment and drug de-velopment of kidney diseases with Apelin as a new target.

Acute kidney injury(AKI)is a syn-drome characterized by rapid decline in renal excre-tory function.Its pathogenesis is still unclear.Stud-ies have shown that macrophages are major play-ers in AKI inflammation,regulating tissue damage and regeneration repair.During AKI inflammation,macrophages can be activated into different func-tional phenotypes through molecular and signaling pathways,regulate different molecules and signal-ing pathways,and determine the progression of AKI.In this paper,the activation of macrophages and the molecular signaling pathways involved in the regulation of AKI in the past five years are re-viewed,and the mechanism of action of macro-phages in AKI is determined,which provides ideas for the study of macrophages as therapeutic tar-gets.

Hematopoietic stem cell transplantation (HSCT) is currently an effective method to cure hematologic malignancies and bone marrow failure diseases, and can restore hematopoietic function destroyed by hematologic malignant diseases. In recent years, HSCT has developed rapidly in China, but pulmonary chronic graft-versus-host disease after transplantation has seriously affected the quality of life and long-term survival of patients. Therefore, this article aims to describe the risk factors, clinical classification, and early diagnosis and treatment strategies of pulmonary chronic graft-versus-host disease, and proposes that lung transplantation is the only effective therapeutic intervention when medical treatment proves ineffective for end-stage pulmonary cGVHD.

Immune-related kidney disease is one of the causes of end-stage renal disease and an important disease type that threatens public health. Farnesoid X receptor (FXR) is a nuclear receptor activated by bile acids, involved in regulating gene expression related to bile acid, lipid, and glucose metabolism. In recent years, the role of FXR in renal immune regulation has received attention. FXR participates in the occurrence and development of immune-related kidney diseases by regulating the differentiation, polarization, activation, recruitment, adhesion, infiltration, and cytokine release of immune cells such as macrophages, dendritic cells, natural killer cells, T lymphocytes, and B lymphocytes. This article reviews renal immune-regulatory mechanisms of FXR in recent years and its potential role in immune-related kidney diseases, to provide a theoretical basis for the prevention and treatment of immune-related kidney diseases targeting FXR.

Immunotherapy following transplantation has long been a central focus in both anti-rejection strategies and the induction of immune tolerance. Regulatory B cells (Bregs) can directly suppress the immune system via the interaction between programmed cell death protein 1 (PD-1) and its ligand programmed death ligand 1 (PD-L1). Additionally, Bregs exert indirect immunosuppressive effects through the secretion of cytokines such as interleukin-10 (IL-10), transforming growth factor-β (TGF-β), and granzyme B (GrB), among which IL-10 plays a particularly critical role. This review summarizes recent progress in the classification, functional characteristics, and activation mechanisms of Bregs, as well as their potential applications in transplantation immunotherapy, aiming to provide a theoretical foundation for Breg-targeted strategies in transplant immune modulation.

Acute kidney injury(AKI)is a syn-drome characterized by rapid decline in renal excre-tory function.Its pathogenesis is still unclear.Stud-ies have shown that macrophages are major play-ers in AKI inflammation,regulating tissue damage and regeneration repair.During AKI inflammation,macrophages can be activated into different func-tional phenotypes through molecular and signaling pathways,regulate different molecules and signal-ing pathways,and determine the progression of AKI.In this paper,the activation of macrophages and the molecular signaling pathways involved in the regulation of AKI in the past five years are re-viewed,and the mechanism of action of macro-phages in AKI is determined,which provides ideas for the study of macrophages as therapeutic tar-gets.

Hematopoietic stem cell transplantation (HSCT) is currently an effective method to cure hematologic malignancies and bone marrow failure diseases, and can restore hematopoietic function destroyed by hematologic malignant diseases. In recent years, HSCT has developed rapidly in China, but pulmonary chronic graft-versus-host disease after transplantation has seriously affected the quality of life and long-term survival of patients. Therefore, this article aims to describe the risk factors, clinical classification, and early diagnosis and treatment strategies of pulmonary chronic graft-versus-host disease, and proposes that lung transplantation is the only effective therapeutic intervention when medical treatment proves ineffective for end-stage pulmonary cGVHD.

Immune-related kidney disease is one of the causes of end-stage renal disease and an important disease type that threatens public health. Farnesoid X receptor (FXR) is a nuclear receptor activated by bile acids, involved in regulating gene expression related to bile acid, lipid, and glucose metabolism. In recent years, the role of FXR in renal immune regulation has received attention. FXR participates in the occurrence and development of immune-related kidney diseases by regulating the differentiation, polarization, activation, recruitment, adhesion, infiltration, and cytokine release of immune cells such as macrophages, dendritic cells, natural killer cells, T lymphocytes, and B lymphocytes. This article reviews renal immune-regulatory mechanisms of FXR in recent years and its potential role in immune-related kidney diseases, to provide a theoretical basis for the prevention and treatment of immune-related kidney diseases targeting FXR.

Immunotherapy following transplantation has long been a central focus in both anti-rejection strategies and the induction of immune tolerance. Regulatory B cells (Bregs) can directly suppress the immune system via the interaction between programmed cell death protein 1 (PD-1) and its ligand programmed death ligand 1 (PD-L1). Additionally, Bregs exert indirect immunosuppressive effects through the secretion of cytokines such as interleukin-10 (IL-10), transforming growth factor-β (TGF-β), and granzyme B (GrB), among which IL-10 plays a particularly critical role. This review summarizes recent progress in the classification, functional characteristics, and activation mechanisms of Bregs, as well as their potential applications in transplantation immunotherapy, aiming to provide a theoretical foundation for Breg-targeted strategies in transplant immune modulation.