The 2019 novel coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has occurred in China and around the world. SARS-CoV-2-infected patients with severe pneumonia rapidly develop acute respiratory distress syndrome (ARDS) and die of multiple organ failure. Despite advances in supportive care approaches, ARDS is still associated with high mortality and morbidity. Mesenchymal stem cell (MSC)-based therapy may be an potential alternative strategy for treating ARDS by targeting the various pathophysiological events of ARDS. By releasing a variety of paracrine factors and extracellular vesicles, MSC can exert anti-inflammatory, anti-apoptotic, anti-microbial, and pro-angiogenic effects, promote bacterial and alveolar fluid clearance, disrupt the pulmonary endothelial and epithelial cell damage, eventually avoiding the lung and distal organ injuries to rescue patients with ARDS. An increasing number of experimental animal studies and early clinical studies verify the safety and efficacy of MSC therapy in ARDS. Since low cell engraftment and survival in lung limit MSC therapeutic potentials, several strategies have been developed to enhance their engraftment in the lung and their intrinsic, therapeutic properties. Here, we provide a comprehensive review of the mechanisms and optimization of MSC therapy in ARDS and highlighted the potentials and possible barriers of MSC therapy for COVID-19 patients with ARDS.
Adoptive Transfer ; Alveolar Epithelial Cells ; pathology ; Animals ; Apoptosis ; Betacoronavirus ; Body Fluids ; metabolism ; CD4-Positive T-Lymphocytes ; immunology ; Clinical Trials as Topic ; Coinfection ; prevention & control ; therapy ; Coronavirus Infections ; complications ; immunology ; Disease Models, Animal ; Endothelial Cells ; pathology ; Extracorporeal Membrane Oxygenation ; Genetic Therapy ; methods ; Genetic Vectors ; administration & dosage ; therapeutic use ; Humans ; Immunity, Innate ; Inflammation Mediators ; metabolism ; Lung ; pathology ; physiopathology ; Mesenchymal Stem Cell Transplantation ; methods ; Mesenchymal Stem Cells ; physiology ; Multiple Organ Failure ; etiology ; prevention & control ; Pandemics ; Pneumonia, Viral ; complications ; immunology ; Respiratory Distress Syndrome, Adult ; immunology ; pathology ; therapy ; Translational Medical Research

As a promising candidate seed cell type in regenerative medicine, mesenchymal stem cells (MSCs) have attracted considerable attention. The unique capacity of MSCs to exert a regulatory effect on immunity in an autologous/allergenic manner makes them an attractive therapeutic cell type for immune disorders. In this review, we discussed the current knowledge of and advances in MSCs, including its basic biological properties, i.e., multilineage differentiation, secretome, and immunomodulation. Specifically, on the basis of our previous work, we proposed three new concepts of MSCs, i.e., "subtotipotent stem cell" hypothesis, MSC system, and "Yin and Yang" balance of MSC regulation, which may bring new insights into our understanding of MSCs. Furthermore, we analyzed data from the Clinical Trials database ( http://clinicaltrials.gov ) on registered clinical trials using MSCs to treat a variety of immune diseases, such as graft-versus-host disease, systemic lupus erythematosus, and multiple sclerosis. In addition, we highlighted MSC clinical trials in China and discussed the challenges and future directions in the field of MSC clinical application.
Cell Differentiation ; Humans ; Immune System Diseases ; immunology ; Mesenchymal Stem Cell Transplantation ; Mesenchymal Stem Cells ; immunology ; physiology ; Randomized Controlled Trials as Topic ; Regenerative Medicine

Human leukocyte antigen (HLA)-matched donors for hematopoietic stem cell transplantation (HSCT) have long been scarce in China. Haploidentical (haplo) donors are available for the vast majority of patients, but toxicity has limited this approach. Three new approaches for haplo-HSCT originated from Italy, China, and USA in 1990 and have been developed to world-renowned system up to now. The Chinese approach have been greatly improved by implementing new individualized conditioning regimens, donor selection based on non-HLA systems, risk-directed strategies for graft-versus-host disease and relapse, and infection management. Haplo-HSCT has exhibited similar efficacy to HLA-matched HSCT and has gradually become the predominant donor source and the first alternative donor choice for allo-HSCT in China. Registry-based analyses and multicenter studies adhering to international standards facilitated the transformation of the unique Chinese experience into an inspiration for the refinement of global practice. This review will focus on how the new era in which "everyone has a donor" will become a reality in China.
China ; Donor Selection ; Graft vs Host Disease ; immunology ; HLA Antigens ; immunology ; Hematologic Neoplasms ; immunology ; surgery ; Hematopoietic Stem Cell Transplantation ; Histocompatibility ; Histocompatibility Testing ; Humans ; Randomized Controlled Trials as Topic ; Transplantation Conditioning

Preterm infants are a special group, and related severe neurological, respiratory, and digestive disorders have high disability/fatality rates. Allogeneic cell transplantation may be an effective method for the prevention and treatment of these diseases. At present, animal studies have been conducted for allogeneic cell transplantation in the treatment of hypoxic-ischemic encephalopathy, bronchopulmonary dysplasia, and necrotizing enterocolitis. The main difficulty of this technique is graft-versus-host reaction (GVHR), and successful induction of immune tolerance needs to be achieved in order to solve this problem. This article reviews the research advances in immune tolerance of allogeneic cell transplantation in preterm infants.
Apoptosis ; Cell Transplantation ; adverse effects ; Cytokines ; physiology ; Graft vs Host Reaction ; Humans ; Immune Tolerance ; Infant, Newborn ; Infant, Premature ; immunology ; Transplantation, Homologous

BackgroundImmunosuppressive agents are still inefficient in preventing biopsy-proven acute rejection (BPAR) after expanded criteria donor (ECD) kidney transplantation. The aim of this study was to investigate the relationships between early immunosuppressive exposure and the development of BPAR.

MethodsWe performed a retrospective study of 58 recipients of ECD kidney transplantation treated with enteric-coated-mycophenolate sodium, tacrolimus (Tac), and prednisone. The levels of mycophenolic acid-area under the curve (MPA-AUC) and Tac Cwere measured at the 1 week and the 1 month posttransplant, respectively. The correlation was assessed by multivariate logistic regression.

ResultsThe occurrence rates of BPAR and antibody-mediated rejection were 24.1% and 10.3%, respectively. A low level of MPA-AUC at the 1 week posttransplant was found in BPAR recipients (38.42 ± 8.37 vs. 50.64 ± 13.22, P < 0.01). In addition, the incidence of BPAR was significantly high (P < 0.05) when the MPA-AUClevel was <30 mg·h·L at the 1 week (15.0% vs. 44.4%) or the Tac Cwas <4 ng/ml at the 1 month posttransplant (33.3% vs. 21.6%). Multivariable logistic regression analysis showed that the MPA-AUC at the 1 week (OR: 0.842, 95% CI: 0.784-0.903) and the Tac Cat the 1 month (OR: 0.904, 95% CI: 0.822-0.986) had significant inverse correlation with BPAR (P < 0.05).

ConclusionsLow-level exposure of MPA and Tac Cin the early weeks posttransplant reflects an increased acute rejection risk, which suggested that MPA-AUC <30 mg·h·L and Tac C <4 ng/ml should be avoided in the first few weeks after transplantation.

Adult ; Female ; Graft Rejection ; immunology ; prevention & control ; Humans ; Immunosuppressive Agents ; chemistry ; therapeutic use ; Kidney Transplantation ; adverse effects ; methods ; Male ; Middle Aged ; Mycophenolic Acid ; chemistry ; therapeutic use ; Retrospective Studies ; Tacrolimus ; chemistry ; therapeutic use ; Time Factors

The gut microbiota is mainly composed of a diverse population of commensal bacterial species and plays a pivotal role in the maintenance of intestinal homeostasis, immune modulation and metabolism. The influence of the gut microbiota on solid organ transplantation has recently been recognized. In fact, several studies indicated that acute and chronic allograft rejection in small bowel transplantation (SBT) is closely associated with the alterations in microbial patterns in the gut. In this review, we focused on the recent findings regarding alterations in the microbiota following SBTand the potential roles of these alterations in the development of acute and chronic allograft rejection. We also reviewed important advances with respect to the interplays between the microbiota and host immune systems in SBT. Furthermore, we explored the potential of the gut microbiota as a microbial marker and/or therapeutic target for the predication and intervention of allograft rejection and chronic dysfunction. Given that current research on the gut microbiota has become increasingly sophisticated and comprehensive, large cohort studies employing metagenomic analysis and multivariate linkage should be designed for the characterization of host-microbe interaction and causality between microbiota alterations and clinical outcomes in SBT. The findings are expected to provide valuable insights into the role of gut microbiota in the development of allograft rejection and other transplant-related complications and introduce novel therapeutic targets and treatment approaches in clinical practice.
Biomarkers ; Gastrointestinal Microbiome ; Graft Rejection ; immunology ; Humans ; Immunity, Mucosal ; Intestine, Small ; microbiology ; transplantation ; Metagenomics ; Transplantation Tolerance ; immunology

To establish optimal reference values for recovered immune cell subsets, we prospectively investigated post-transplant immune reconstitution (IR) in 144 patients who received allogeneic stem cell transplantation (allo- SCT) and without showing any of the following events: poor graft function, grades II‒IV acute graft-versus-host disease (GVHD), serious chronic GVHD, serious bacterial infection, invasive fungal infection, or relapse or death in the first year after transplantation. IR was rapid in monocytes, intermediate in lymphocytes, CD3 Tcells, CD8 T cells, and CD19 B cells, and very slow in CD4 T cells in the entire patient cohort. Immune recovery was generally faster under HLA-matched sibling donor transplantation than under haploidentical transplantation. Results suggest that patients with an IR comparable to the reference values display superior survival, and the levels of recovery in immune cells need not reach those in healthy donor in the first year after transplantation.We suggest that data from this recipient cohort should be used as reference values for post-transplant immune cell counts in patients receiving HSCT.
Adolescent ; Adult ; Child ; Child, Preschool ; China ; Disease-Free Survival ; Female ; Graft vs Host Disease ; immunology ; mortality ; HLA Antigens ; immunology ; Hematopoietic Stem Cell Transplantation ; Humans ; Immune Reconstitution ; Male ; Middle Aged ; Reference Values ; Siblings ; T-Lymphocytes ; immunology ; Tissue Donors ; Transplantation, Homologous ; Young Adult

BACKGROUND: The interaction between killer immunoglobulin-like receptors (KIRs) and HLA class I regulates natural killer (NK) cell cytotoxicity and function. The impact of NK cell alloreactivity through KIR in liver transplantation remains unelucidated. Since the frequency of HLA-C and KIR genotypes show ethnic differences, we assessed the impact of HLA-C, KIR genotype, or KIR-ligand mismatch on the allograft outcome of Korean liver allografts. METHODS: One hundred eighty-two living donor liver transplant patients were studied. Thirty-five patients (19.2%) had biopsy-confirmed acute rejection (AR), and eighteen (9.9%) had graft failure. The HLA-C compatibility, KIR genotypes, ligand-ligand, and KIR-ligand matching was retrospectively investigated for association with allograft outcomes. RESULTS: Homozygous C1 ligands were predominant in both patients and donors, and frequency of the HLA-C2 allele in Koreans was lower than that in other ethnic groups. Despite the significantly lower frequency of the HLA-C2 genotype in Koreans, donors with at least one HLA-C2 allele showed higher rates of AR than donors with no HLA-C2 alleles (29.2% vs 15.7%, P=0.0423). Although KIR genotypes also showed ethnic differences, KIR genotypes and the number of activating KIR/inhibitory KIR were not associated with the allograft outcome. KIR-ligand mismatch was expected in 31.6% of Korean liver transplants and had no impact on AR or graft survival. CONCLUSIONS: This study could not confirm the clinical impact of KIR genotypes and KIR-ligand mismatch. However, we demonstrated that the presence of HLA-C2 allele in the donor influenced AR of Korean liver allografts.
Adult ; Alleles ; Asian Continental Ancestry Group/*genetics ; Female ; Genotype ; Graft Rejection ; Graft Survival ; HLA-C Antigens/*genetics ; Homozygote ; Humans ; Killer Cells, Natural/cytology/immunology ; Ligands ; *Liver Transplantation ; Male ; Middle Aged ; Proportional Hazards Models ; Receptors, KIR/chemistry/*genetics/metabolism ; Republic of Korea ; Tissue Donors ; Transplantation, Homologous

OBJECTIVETo investigate the effects of adipose-derived stem cells (ADSC) and non-methylated CpG-oligodeoxynucleotides (CpG-ODN) on the expression of peripheral blood CD4CD25regulatory T (Treg) cells in young mice with food allergy, as well as their immune intervention effects.

METHODSA total of 40 female BALB/c mice were randomly divided into control group, allergic group, ADSC treatment group, and CpG-ODN treatment group, with 10 mice in each group. A mouse model of food allergy was established by intraperitoneal injection and intragastric administration of ovalbumin (OVA) for sensitization and challenge. The mice in the control group were treated with normal saline at the same dose; the mice in the ADSC treatment group were given intraperitoneal injection of ADSC (1×10cells for each mouse) before and after OVA challenge, and those in the CpG-ODN treatment group were given intraperitoneal injection of non-methylated CpG-ODN solution (40 μg for each mouse) at 1 hour before challenge by gavage. The allergic symptom scores were determined for each group after model establishment. ELISA was used to measure the serum level of OVA-IgE. Flow cytometry was used to measure the percentage of peripheral blood CD4CD25Treg cells. Hematoxylin and eosin staining was used for the pathological analysis of the jejunum.

RESULTSThe allergic group had significantly higher allergic symptom scores and serum level of OVA-IgE than the control group (P<0.05). There were no significant differences in the allergic symptom score and the serum level of OVA-IgE between the ADSC treatment group and the CpG-ODN treatment group (P>0.05), but these two groups had significantly lower allergic symptom scores and serum level of OVA-IgE than the allergic group and significantly higher allergic symptom scores and serum level of OVA-IgE than the control group (P<0.01). The allergic group had a significantly lower percentage of peripheral blood CD4CD25Treg cells than the control group (P<0.05). The ADSC treatment group and the CpG-ODN treatment group had a significantly higher percentage of peripheral blood CD4CD25Treg cells than the allergic group (P<0.05); there were no significant differences between these two groups or between them and the control group (P>0.05). Pathological results showed structural damage and edema in the jejunal villi, a large number of eosinophils, and lymphocyte infiltration in the allergic group, while the ADSC treatment group and the CpG-ODN treatment group had less structural damage and edema in the jejunal villi, a lower number of eosinophils, and less lymphocyte infiltration.

CONCLUSIONSADSC and non-methylated CpG-ODN have a certain effect in the treatment of food allergy and can increase the percentage of peripheral blood CD4CD25Treg cells and reduce the level of OVA-IgE. They may be associated with the induction of immune tolerance and these two treatment have comparable effects. Detailed mechanisms of action still need further investigation.

Adipose Tissue ; cytology ; Adjuvants, Immunologic ; pharmacology ; Animals ; Female ; Food Hypersensitivity ; immunology ; therapy ; Immunoglobulin E ; blood ; Mice ; Mice, Inbred BALB C ; Oligodeoxyribonucleotides ; pharmacology ; Ovalbumin ; immunology ; Stem Cell Transplantation ; T-Lymphocytes, Regulatory ; drug effects ; immunology

Mesenchymal stem cell (MSC) transplantation is considered one of the most promising therapeutic strategies for the repair of brain injuries and plays an important role in various links of nerve repair. Recent studies have shown that MSC-derived exosomes may dominate the repair of brain injuries and help to promote angiogenesis, regulate immunity, inhibit apoptosis, and repair the nerves, and therefore, they have a great potential in the treatment of brain injuries in neonates. With reference to these studies, this article reviews the mechanism of action of exosomes in the repair of brain injuries and related prospects and challenges, in order to provide new directions for the treatment of brain injuries in neonates with stem cells.
Apoptosis ; Brain Injuries ; therapy ; Exosomes ; physiology ; Humans ; Inflammation ; prevention & control ; Mesenchymal Stem Cell Transplantation ; Neovascularization, Physiologic ; T-Lymphocytes ; immunology