Objective To explore the therapeutic effect and mechanism of umbilical cord mesenchymal stem cells (UC-MSC) in rats with primary graft dysfunction after lung transplantation. Methods Twenty-four male Lewis rats were randomly divided into donor and recipient groups, with 12 rats in each group. The recipients were further divided into 3 groups: blank control group, negative control group, and treatment group, with 4 rats in each group. The color, size and texture of the transplanted lungs were observed 72 h after lung transplantation. The ventilation status and progression of consolidation in the transplant lungs of rats in each group were evaluated by micro-CT. Plasma, transplant lung tissue and alveolar lavage fluid samples of recipient rats were collected. The wet/dry ratio of lung tissue was measured to evaluate the degree of pulmonary edema. Hematoxylin-eosin (HE) staining was used to evaluate the degree of lung tissue damage. Terminal deoxyribonucleic acid transferase mediated dUTP nick end labeling (TUNEL) staining was used to evaluate cell apoptosis. Myeloperoxidase (MPO) activity in lung tissue was detected, and enzyme-linked immunosorbent assay (ELISA) was used to detect interleukin (IL)-6, IL-10 and tumor necrosis factor (TNF)-α levels in plasma and alveolar lavage fluid. Results The appearance of the transplant lungs in the negative control group was significantly different from that of the autologous lungs, while the transplant lungs in the treatment group were almost identical in color to the autologous lungs compared to the blank control group. Compared with the negative control group, the treatment group showed reduced alveolar exudate and more intact airway epithelial cell structure. No alveolar exudate was observed in the blank control group, and the structure of the airways and alveoli remained normal. The treatment group had lower apoptosis rate of airway epithelial cells, lung tissue wet/dry ratio, and MPO activity compared to the negative control group (all P < 0.05). The levels of IL-6 and TNF-α in the bronchoalveolar lavage fluid of the treatment group were lower than those in the negative control group, while the level of IL-10 was higher than that in the negative control group and the blank control group (all P < 0.05). There were no statistically significant differences in the levels of cytokines in plasma among each group (all P > 0.05). Conclusions UC-MSC may effectively alleviate the severity of primary graft dysfunction in rats by reducing the apoptosis rate of cells in lung tissue and inhibiting inflammatory responses.

Viral infection has always been a significant challenge to human health. Transplant recipients, including those who have undergone solid organ transplantation and allogeneic hematopoietic stem cell transplantation, are at high risk of viral infection due to their weak immune function under immunosuppressive therapy. Unlike the general population, transplant recipients are prone to pneumonia and even severe pneumonia after respiratory viral infection, which requires close attention from clinicians. Therefore, this article reviews the clinical characteristics and special management of viral infection in this population, focusing on the epidemiological features of common respiratory viral infection in transplant recipients, early diagnosis and intervention after infection, severe warning signs and drug treatment strategies, for the reference of clinical colleagues.

Objective To evaluate clinical efficacy of lung transplantation for lung chronic graft-versus-host disease (cGVHD) after hematopoietic stem cell transplantation (HSCT). Methods Clinical data of 12 patients undergoing lung transplantation for lung cGVHD were retrospectively analyzed. Preoperative clinical manifestations and involved organs of patients were analyzed. The lung function before and after lung transplantation was compared, and the survival of patients after lung transplantation was analyzed. Results Eleven patients underwent HSCT due to primary hematological malignancies, including 9 cases of leukemia, 1 case of myelodysplastic syndrome, 1 case of lymphoma. And 1 case underwent HSCT for systemic lupus erythematosus. Among 12 cGVHD patients, skin involvement was found in 8 cases, oral cavity involvement in 5 cases, gastrointestinal tract involvement in 4 cases and liver involvement in 3 cases. All 12 patients developed severe respiratory failure caused by cGVHD before lung transplantation, including 9 cases of typeⅡ respiratory failure and 3 cases of type Ⅰ respiratory failure. Two patients underwent right lung transplantation, 2 cases of left lung transplantation and 8 cases of bilateral lung transplantation. The interval from HSCT to lung transplantation was 75 (19-187) months. Upon the date of submission, postoperative follow-up time was 18 (7-74) months. Ten patients survived, 1 died from severe hepatitis at postoperative 22 months, and 1 died from gastrointestinal bleeding at postoperative 6 months. No recurrence of primary diseases was reported in surviving patients. Conclusions Lung transplantation is an efficacious treatment for lung cGVHD after HSCT, which may prolong the survival time and improve the quality of life of the recipients.

With the optimization of surgical technologies and postoperative management regimens, the number of lung transplantation has been significantly increased, which has become an important treatment for patients with end-stage lung disease. However, due to the impact of comprehensive factors, such as bronchial ischemia and immunosuppression, the incidence of airway stenosis after lung transplantation is relatively high, which severely affects postoperative survival and quality of life of lung transplant recipients. In recent years, with the improvement of perioperative management, organ preservation and surgical technologies, the incidence of airway stenosis after lung transplantation has been declined, but it remains at a high level. Early diagnosis and timely intervention play a significant role in enhancing clinical prognosis of patients with airway stenosis. In this article, the general conditions, diagnosis, treatment and prevention of airway stenosis after lung transplantation were reviewed, aiming to provide reference for comprehensive management of airway stenosis after lung transplantation and improving clinical prognosis of lung transplant recipients.

Nocardiosis is a collective term for tissue and organ damage caused by Nocardia infection.Solid organ transplant recipients(SOTR)are at an increased risk of various pathogen infections,including Nocardia infection,due to immunosuppressive therapy which weakens their immune function.The diagnosis of nocardiosis has been challenging in the past.With the advent of molecular biology and other diagnostic methods,the diagnostic rate has significantly improved.Nocardia not only prone to cause necrotic pulmonary lesions but also invade other organs and tissues,such as intracranial infections and skin soft tissue infections,and can develop into systemic disseminated infections.For SOTR,nocardiosis is a potentially fatal disease with a fatality as high as 30%.Therefore,this article reviews the clinical characteristics of common nocardiosis in SOTR,new diagnostic technologies,and different anti-infective treatment strategies,aiming to provide a reference for the prevention and treatment of nocardiosis in clinical SOTR.

Long-term use of immunosuppressants result in an immunocompromised state, repeated hospitalizations and dosing of broad-spectrum antibiotics. Presence of transplant-associated diabetes and cadaveric donations are contributing factors to a higher risk of invasive fungal disease (IFD ) among solid organ transplantation (SOT) recipients. Furthermore, the epidemiology of IFD in SOT recipients has continuously evolved in recent years. Understanding the current epidemiological status of IFD in SOT recipients, becoming familiar with new diagnostic technologies for IFD and mastering the characteristics of novel antifungal medications may further improve the prognosis for recipients. This review summarized the incidence, pathogen composition, new diagnostic technologies and recently marketed novel antifungal medications for IFD in SOT recipients, aiming to offer references for clinical practices.

Objective:Analysis of surgical strategies for atrial functional mitral regurgitation with atrial fibrillation.Methods:Retrospective analysis of 112 patients with mitral regurgitation and atrial fibrillation between June 2017 and January 2023. Among them, 56 cases were severe atrial functional mitral regurgitation with atrial fibrillation, and the other 56 cases were degenerative mitral regurgitation with atrial fibrillation. All patients underwent maze Ⅳ procedure and mitral valve surgery. Follow up will be conducted through outpatient follow-up and telephone calls. The condition of postoperative mitral valve is obtained through echo. The postoperative cardiac rhythm is based on the patient's conscious symptoms, electrocardiogram, 24 hour dynamic electrocardiogram.Results:The comparison of preoperative basic data shows that the age, duration of atrial fibrillation, and comorbidity of patients with atrial functional mitral regurgitation are significantly higher than those in the degenerative mitral regurgitation group. All patients successfully completed the surgery. Postoperative death occurred in 2 cases in the atrial mitral regurgitation group. The causes of death were ARDS and pulmonary infection, respectively. The main postoperative complications include bleeding, low cardiac output, pulmonary infection, and acute kidney injury. During follow-up, 43 patients (79.6%) in the atrial mitral regurgitation group maintained sinus rhythm, while 49 patients (87.5%) in the degenerative group. However, there was no statistically significant difference in the Kaplan- Meier curves. In the atrial mitral regurgitation group, there were 47 cases with no mitral regurgitation, 4 cases with mild regurgitation, and 1 case with moderate regurgitation. In the degenerative group, there were 42 cases with no mitral regurgitation, 6 cases with mild regurgitation, 1 case with moderate regurgitation, and 1 case with severe regurgitation. The risk for atrial fibrillation recurrence in the atrial mitral regurgitation is related to postoperative left atrial diameter greater than 50 mm, while in the degenerative group, atrial fibrillation recurrence is related to postoperative left atrial diameter greater than 50 mm and residual mitral regurgitation. Conclusion:Mitral valve repair combined with maze Ⅳ procedure is an effective treatment for patients with severe atrial functional mitral regurgitation and atrial fibrillation. Further improving the success rate of atrial fibrillation and reducing surgical trauma will benefit patients in the future.

Progressive multifocal leukoencephalopathy (PML) is a rare and yet serious central nervous system disorder due to JC viral infection.PML occurs predominantly in immunocompromised individuals, including solid organ transplant (SOT) recipients.Clinically, SOT-related PML commonly presents as cognitive and behavioral impairments. Pathologically, PML is characterized by multifocal demyelinating lesions, with neuroimaging technique typically revealing white matter damage in the temporoparietal regions. Clinical diagnosis usually involves integrating clinical manifestations, cranial magnetic resonance imaging, and detection of JC virus in cerebrospinal fluid. Currently, specific medications for PML are lacking, and the treatment mainly relies on supportive care and immunomodulatory strategies. The prognosis of PML remains unfavorable, early diagnosis and enhanced adaptive immune responses are crucial for PML management in SOT recipients.

Currently COVID-19 variant virology and its prevalence both domestically and internationally have become a new norm.With the emergence of Omicron variant, the protective effect of original preventive measures against reinfection with variant strains has declined.Current prevalence of COVID-19 variant strains, the mechanisms of reinfection and the risks of reinfection in solid organ transplant recipients(SOTR)were discussed.Immunocompromised individuals, especially SOTR, face an elevated risk of multiple infections, such as seasonal influenza and respiratory syncytial virus, during high transmission seasons for respiratory viruses and require special care and protection.With the introduction of several small molecule drugs, there are now more options available for antiviral regimens.This review offered a brief overview of the characteristics of COVID-19 variant strains in the current scenario, disease incidence among SOTR in China, unique features of novel antiviral agents and optimizing the selection of diagnostic and therapeutic plans.

Objective:To explore the abundance, diversity, and structural changes of early postoperative pulmonary bacterial microbiota in lung transplant recipients.Methods:Recruiting 40 recipients who underwent lung transplantation surgery at the First Affiliated Hospital of Guangzhou Medical University from October 2020 to May 2022 for the study.All recipients did not receive antibiotic treatment within 4 weeks prior to surgery, and all recipients received a unified immunosuppressive and anti infection regimen after surgery.The bronchoalveolar lavage fluid(BALF) was collected from the amputated lung in vitro before the transplantation for 16S ribosomal RNA sequencing and flora analysis.BALF was also collected at the scheduled time from the transplanted lung on the 7th, 14th and 30th days post transplantaion for analysis.Results:The study included a total of 40 recipients who did not receive antibiotic treatment within 4 weeks before surgery, including 35 males.Among the study participants, there were 14 cases of primary obstructive pulmonary disease, 19 cases of interstitial lung disease, 3 cases of occupational lung disease, and 4 others.Microbiome in BALF of transplanted and detached autologous lungs at the first week after surgery α( P<0.05) and β diversity is statistically significant( R2=0.08, P=0.001), and the bacterial community in the transplanted lungs α Diversity is lower than that of explant lungs.Starting from the second week after surgery, the richness and species diversity of the transplanted lung microbiota gradually increase.The bacterial structure was also changed with postoperative time, and the relative abundance of the same bacterial species were varied at different time points.The bacterial community in BALF was mainly dominated by Proteobacteria both explant lungs and transplant lungs.The relative abundance of Staphylococcus and Acinetobacter genera at the BALF in transplanted lungs was higher than that in explant lung samples, but their relative abundance decreased over time after surgery. Conclusions:The α diversity of the early postoperative pulmonary microbiota after lung transplantation was lower than that of the amputated autologous lung, and the bacterial richness and species diversity in the microbiota of the transplanted lung gradually increased at the second week after the transplantation.The bacterial microbiota of the transplanted lung is changed complicatedly with time.