Cytotoxic CD4⁺ T cells (CD4⁺ CTLs) represent a novel subset of T cells with cytotoxic effects. They recognize target cells in an antigen-specific manner, relying on class II major histocompatibility complex (MHC-II) interactions. CD4⁺ CTLs exert cytotoxic effects on target cells by secreting cytotoxic molecules such as granzymes, perforin, and granulysin. Recent studies have revealed their significant roles in various autoimmune diseases. This review focuses on the differentiation, phenotypic characteristics, and roles of CD4⁺ CTLs in different types of autoimmune disorders, aiming to provide new insights for the prevention and treatment of these diseases.
Humans ; Autoimmune Diseases/immunology* ; CD4-Positive T-Lymphocytes/immunology* ; Animals ; T-Lymphocytes, Cytotoxic/immunology* ; Perforin/immunology* ; Granzymes/immunology*

OBJECTIVES: To evaluate the clinical value of CD4⁺ cell percentage (CD4⁺%) and NK cell percentage (NK%) in predicting treatment outcomes in children with aplastic anemia (AA), providing a reference for precise diagnosis and treatment. METHODS: This retrospective study analyzed the clinical data of AA children treated with cyclosporine A at the First Affiliated Hospital of Xinjiang Medical University from January 2019 to April 2024. The study involved 48 AA children as the observation group and 50 children undergoing medical check-ups during the same period as the control group. Lymphocyte subset data were collected from both groups to analyze differences and their relationship with treatment efficacy. Based on hematological responses, the observation group was divided into an effective group of 18 patients (HR group, including complete and partial remission) and an ineffective group of 30 patients (NHR group, including non-remission). RESULTS: Univariate analysis showed that NK% in the observation group was significantly lower than that in the control group (P<0.05). The observation group was followed up for 3 months. The HR group had a lower CD4⁺% than the NHR group (P=0.018) and a higher NK% than the NHR group (P=0.029). Multivariate logistic regression analysis indicated that a high CD4⁺% was a risk factor for poor treatment efficacy (OR=1.062), whereas a high NK% was a protective factor (OR=0.820). The area under the curve for the prediction of HR in pediatric AA by combining CD4⁺% and NK% was 0.812. CONCLUSIONS A higher CD4⁺% at diagnosis is a predictor of poor treatment response, whereas a higher NK% is associated with better outcomes.
Humans ; Anemia, Aplastic/blood* ; Male ; Female ; Killer Cells, Natural ; Child ; Retrospective Studies ; Child, Preschool ; Prognosis ; Adolescent ; CD4-Positive T-Lymphocytes ; Infant

OBJECTIVES: To investigate the characteristics of immune cell infiltration in tumor samples from Chinese patients with clear cell renal cell carcinoma (ccRCC) and the correlation of immune cell infiltration with tumor stage and response to immunotherapy. METHODS: Tumor samples and clinicopathological data were collected from 154 ccRCC patients treated in Nanfang Hospital, Southern Medical University from October, 2020 to October, 2023. The immune cell types infiltrating the tumor tissues were identified using immunohistochemistry and immunofluorescence staining, and their correlations with the patients' clinicopathological characteristics were analyzed. Patient-derived tumor tissue fragment models (PDTF) models, constructed using tumor tissues from 22 patients, were treated with PD-1 monoclonal antibody, and T cell activation was detected using flow cytometry to assess the patients' responses to immunotherapy. RESULTS: In Chinese ccRCC patients included in this study, CD8⁺ T cells, CD4⁺ T cells, and CD3⁺ T cells were the most abundant in the tumor tissues. Higher infiltration levels of CD3⁺ T cells (P=0.004), PD-1⁺ T cells (P=0.020), CD68⁺ T cells (P=0.049), CD79⁺ T cells (P=0.049), and Tryptase⁺ cells (P=0.049) were all positively correlated with a larger tumor size (≥5 cm). A higher infiltration level of CD4⁺ T cells was associated with a lower tumor stage. Patients with higher International Society of Urological Pathology (ISUP) grades had higher infiltration levels of CD3⁺ T cells (P=0.023), CD8⁺ T cells (P=0.045), PD-1⁺ T cells (P=0.014), CD20⁺ B cells (P=0.020) and CD79⁺ B cells (P=0.049), and lower levels of Tryptase⁺ cells (P=0.001). Patients with abundant infiltrating immune cells tended to have better responses to immunotherapy. CONCLUSIONS The infiltrating immune cells are heterogeneous in Chinese ccRCC patients, and immune cell infiltration characteristics are closely correlated with clinicopathological parameters of the patients.
Humans ; Carcinoma, Renal Cell/pathology* ; Kidney Neoplasms/pathology* ; Immunotherapy ; Male ; Lymphocytes, Tumor-Infiltrating/immunology* ; Female ; Middle Aged ; CD8-Positive T-Lymphocytes/immunology* ; Aged ; T-Lymphocytes/immunology* ; Programmed Cell Death 1 Receptor/immunology* ; Adult ; CD4-Positive T-Lymphocytes/immunology* ; Neoplasm Staging

Infiltration and activation of peripheral immune cells are critical in the progression of multiple sclerosis and its experimental animal model, experimental autoimmune encephalomyelitis (EAE). This study investigates the role of high mobility group box 1 (HMGB1) in oligodendrocyte precursor cells (OPCs) in modulating pathogenic T cells infiltrating the central nervous system through the blood-brain barrier (BBB) by using OPC-specific HMGB1 knockout (KO) mice. We found that HMGB1 released from OPCs promotes BBB disruption, subsequently allowing increased immune cell infiltration. The migration of CD4+ T cells isolated from EAE-induced mice was enhanced when co-cultured with OPCs compared to oligodendrocytes (OLs). OPC-specific HMGB1 KO mice exhibited lower BBB permeability and reduced immune cell infiltration into the CNS, leading to less damage to the myelin sheath and mitigated EAE progression. CD4+ T cell migration was also reduced when co-cultured with HMGB1 knock-out OPCs. Our findings reveal that HMGB1 secretion from OPCs is crucial for regulating immune cell infiltration and provides insights into the immunomodulatory function of OPCs in autoimmune diseases.
Animals ; Encephalomyelitis, Autoimmune, Experimental/metabolism* ; HMGB1 Protein/deficiency* ; Mice, Knockout ; Oligodendrocyte Precursor Cells/immunology* ; Mice, Inbred C57BL ; CD4-Positive T-Lymphocytes/immunology* ; Cell Movement ; Blood-Brain Barrier/immunology* ; Mice ; Myelin Sheath/pathology* ; Disease Models, Animal ; Coculture Techniques ; Oligodendroglia/metabolism* ; Female ; Cells, Cultured

Multiple sclerosis (MS) is a neuroinflammatory demyelinating disease, mediated by pathogenic T helper 17 (Th17) cells. However, the therapeutic effect is accompanied by the fluctuation of the proportion and function of Th17 cells, which prompted us to find the key regulator of Th17 differentiation in MS. Here, we demonstrated that the triggering receptor expressed on myeloid cells 2 (TREM-2), a modulator of pattern recognition receptors on innate immune cells, was highly expressed on pathogenic CD4-positive T lymphocyte (CD4⁺ T) cells in both patients with MS and experimental autoimmune encephalomyelitis (EAE) mouse models. Conditional knockout of Trem-2 in CD4⁺ T cells significantly alleviated the disease activity and reduced Th17 cell infiltration, activation, differentiation, and inflammatory cytokine production and secretion in EAE mice. Furthermore, with Trem-2 knockout in vivo experiments and in vitro inhibitor assays, the TREM-2/zeta-chain associated protein kinase 70 (ZAP70)/signal transducer and activator of transcription 3 (STAT3) signal axis was essential for Th17 activation and differentiation in EAE progression. In conclusion, TREM-2 is a key regulator of pathogenic Th17 in EAE mice, and this sheds new light on the potential of this therapeutic target for MS.
Animals ; Humans ; Mice ; CD4-Positive T-Lymphocytes/pathology* ; Cell Differentiation ; Encephalomyelitis, Autoimmune, Experimental/metabolism* ; Mice, Inbred C57BL ; Multiple Sclerosis ; Th1 Cells/pathology*

Objective To clarify the mechanism that HIV infection mediates mitochondrial damage of CD4⁺ T lymphocytes (CD4⁺ T cells) through mitogen-activated protein kinase (MAPK) pathway. Methods From October 1st, 2022 to March 31st, 2023, 47 HIV-infected people who received antiretroviral therapy (ART) for 4 years were recruited, including 22 immune non-responders (INR) and 25 responders (IR); and 26 sex and age-matched control participants (HC) who were negative for HCV, HBV, and HIV infections. The immune parameters were analyzed by flow cytometry. Finally, peripheral blood mononuclear cells (PBMCs) from HC or HIV patients were treated with MAPK pathway inhibitor SB203580, and the changes of mitochondrial function of CD4⁺ T cells were observed. Results Compared with HC group, the proportion of CD4⁺ T cells in PBMCs in INR group and IR group was significantly lower, and the proportion of CD4⁺ T cells in PBMCs in INR group was significantly lower than that in IR group. In addition, the proportion of naive (CD45RA⁺CD27⁺)T cells in PBMCs in INR group was significantly lower than that in HC group and IR group. Compared with HC group and IR group, the proportions of CD4⁺PD-1⁺, CD4⁺Av⁺ and CD4⁺MO⁺ in PBMCs in INR group and the proportions of CD45RA⁺CD27⁺PD-1⁺, CD45RA⁺CD27⁺Av⁺, CD45RA⁺CD27⁺MO⁺ in CD4⁺ T cell subsets increased significant. Compared with HC-con group, the basal respiration, maximal respiration and adenosine triphosphate(ATP) production of CD4⁺ T cells in HIV-con group decreased significantly, and JC-1 (green/red) in CD4⁺ T cells increased significantly. Compared with HIV-con group, the basal respiration, maximal respiration, ATP production and respiratory potential of CD4⁺ T cells in HIV-SB203580 group increased significantly, and the JC-1 (green/red) in CD4⁺ T cells decreased significantly. Conclusion Abnormal activation of the MAPK signaling pathway is observed in HIV patients receiving ART treatment, especially in CD4⁺ T cells of INR patients, which may lead to impaired mitochondrial function and abnormal CD4⁺ T cell homeostasis.
Humans ; HIV Infections/immunology* ; Male ; Mitochondria/drug effects* ; Female ; CD4-Positive T-Lymphocytes/metabolism* ; Adult ; Middle Aged ; MAP Kinase Signaling System/drug effects* ; Pyridines/pharmacology* ; Imidazoles/pharmacology* ; Leukocytes, Mononuclear/immunology*

OBJECTIVES: To explore the prophylactic and therapeutic effects of Alhagi maurorum ethanolic extract (AME) in concanavalin A (Con A)-induced hepatitis (CIH) as well as possible underlying mechanisms. METHODS: Polyphenols in AME were characterized using high performance liquid chromatography (HPLC). Swiss albino mice were divided into 4 groups. Normal group received intravenous phosphate-buffered saline (PBS); Con A group received 40 mg/kg intravenous Con A. Prophylaxis group administered 300 mg/(kg·d) AME orally for 5 days before Con A intervention. Treatment group received intravenous Con A then administered 300 mg/kg AME at 30 min and 3 h after Con A intervention. After 24 h of Con A injection, hepatic injury, oxidative stress, and inflammatory mediators were assessed. Histopathological examination and markers of apoptosis, inflammation, and CD4⁺ cell infiltration were also investigated. RESULTS: HPLC analysis revealed that AME contains abundant polyphenols with pharmacological constituents, such as ellagic acid, gallic acid, ferulic acid, methylgallate, and naringenin. AME alleviated Con A-induced hepatic injury, as manifested by a significant reduction in alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase (P<0.01). Additionally, the antioxidant effect of AME was revealed by a significant reduction in oxidative stress markers (nitric oxide and malondialdehyde) and restored glutathione (P<0.01). The levels of proinflammatory cytokines (tumor necrosis factor-α, interferon-γ, and interleukin-6) and c-Jun N-terminal kinase (JNK) activity were reduced (P<0.01). Histopathological examination of liver tissue showed that AME significantly ameliorated necrotic and inflammatory lesions induced by Con A (P<0.01). Moreover, AME reduced the expression of nuclear factor kappa B, pro-apoptotic protein (Bax), caspase-3, and CD4⁺ T cell hepatic infiltration (P<0.01). The expression of anti-apoptotic protein Bcl-2 was increased (P<0.01). CONCLUSION AME has hepatoprotective and ameliorative effects in CIH mice. These beneficial effects are likely due to the anti-inflammatory, antioxidant, and anti-apoptotic effects of the clinically important polyphenolic content. AME could be a novel and promising hepatoprotective agent for managing immune-mediated hepatitis.
Animals ; Concanavalin A ; Mice ; Polyphenols/pharmacology* ; Liver/drug effects* ; Plant Extracts/therapeutic use* ; Camelus ; Oxidative Stress/drug effects* ; Male ; Protective Agents/pharmacology* ; Chemical and Drug Induced Liver Injury/prevention & control* ; Apoptosis/drug effects* ; Hepatitis/pathology* ; Antioxidants/pharmacology* ; CD4-Positive T-Lymphocytes/drug effects* ; Inflammation Mediators/metabolism*

Nucleolar complex associated 4 homolog (NOC4L) is a key factor in ribosome biogenesis, and this study aims to investigate its roles in activated T cells from the perspective of translation regulation. Firstly, flow cytometry was employed to determine the expression levels of NOC4L in the CD4⁺ T cells under different conditions in the transgenic reporter mice expressing Noc4l^mCherry. Subsequently, the expression of NOC4L along with cell proliferation was examined under Th1 and Th17 polarization conditions. Finally, in vitro experiments were conducted to identify the proteins interacting with NOC4L during the activation of Th1 and Th17 cells, on the basis of which the potential mechanisms of NOC4L were explored. The results showed that the expression level of NOC4L increased in activated CD4⁺ T cells, and the expression of NOC4L was closely associated with the proliferation and division of activated T cells. The in vitro experiments revealed interactions between NOC4L and proteins involved in ribosome assembly and cell proliferation during T cell activation. These findings lay a foundation for probing into the post-transcriptional regulation in helper T cells and hold profound significance for understanding the activation and regulatory mechanisms of T cells.
Animals ; Mice ; Lymphocyte Activation ; Cell Proliferation ; Mice, Transgenic ; Nuclear Proteins/genetics* ; Th1 Cells/immunology* ; Th17 Cells/metabolism* ; CD4-Positive T-Lymphocytes/immunology* ; Ribosomes/metabolism*

Apoptosis ; Proteins/metabolism* ; Mitochondria/metabolism* ; CD4-Positive T-Lymphocytes

OBJECTIVE: To explore the relationship between occurrence of acute graft-versus-host disease (aGVHD) and various immune cell composition in patients with acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: The clinical data of 104 patients with AML undergoing allo-HSCT in our hospital were retrospectively analyzed, and the hematopoietic reconstitution and occurrence of GVHD were analyzed. Flow cytometry was used to detect the proportion of various types of immune cells in the grafts, the number of graft composition in patients with different degrees of aGVHD was calculated and compared, and to analyze the correlation between the severity of aGVHD in AML patients after allo-HSCT and the immune cell components in the graft. RESULTS: There was no significant difference in the time of hematopoietic reconstitution between the high number group of total number of nucleated cells (TNC) and the low number group, while the time of neutrophil and platelet reconstruction in the high number of CD34 group was significantly faster than that in the low number of CD34 group (P＜0.05), and the total hospital stay also tends to be shorten. Compared with patients in 0-Ι aGVHD group, both HLA-matched and HLA-haploidentical transplantation, the infusion amounts of CD3⁺ cells, CD3⁺CD4⁺ cells, CD3⁺CD8⁺ cells, NK cells and CD14⁺ monocytes were higher in patients of Ⅱ-Ⅳ aGVHD group， but the difference was not statistically significant (P>0.05); In addition, in patients with HLA-haploidentical transplantation, the number of CD4⁺CD25⁺ cells in Ⅱ-Ⅳ aGVHD group was significantly lower than that in 0-Ι aGVHD group (P<0.05), and the same trend was also observed in HLA-matched transplanted patients, but the difference was not significant (P=0.078). CONCLUSION High number of CD34⁺ cells in the graft is beneficial to hematopoietic reconstitution in AML patients. To a certain degree, high number of CD3⁺ cells, CD3⁺CD4⁺ cells, CD3⁺CD8⁺ cells, NK cells and CD14⁺ cells tend to increase the occurrence of aGVHD, but high number of CD4⁺CD25⁺ regulatory T cells is beneficial to reduce the incidence of aGVHD in AML patients.
Humans ; Retrospective Studies ; Hematopoietic Stem Cell Transplantation/adverse effects* ; CD4-Positive T-Lymphocytes ; Leukemia, Myeloid, Acute/complications* ; Graft vs Host Disease