Kaposi sarcoma following solid organ transplantation is a rare and underreported complication, with few cases documented globally concerning its origin from liver grafts.This case report describes an Asian woman who developed Kaposi sarcoma in a liver graft following living donor liver transplantation for end-stage liver disease resulting from hepatitis D virus. In accordance with current guidelines, standard immunosuppression was discontinued, and mammalian target of rapamycin (mTOR) inhibitors were initiated. The use of mTOR inhibitors led to the complete resolution of the liver graft lesions within 9 months. However, subsequent follow-up revealed several complications, including late anastomotic biliary stricture, extensively drug-resistant Klebsiella pneumoniae infection, and subtotal hydrothorax. These complications required intensive care unit admission, biliary stenting, oxygen therapy, and pleural drainage. Despite the severity of her condition, the patient fully recovered and showed no signs of recurrence throughout the 64-month follow-up period. To our knowledge, this is the first reported case of Kaposi sarcoma in a liver graft with such an extended follow-up.

Biliopleural fistula (BF) is an uncommon complication that can occur after liver transplantation (LT). This condition, characterized by pleural biliary effusion, can lead to severe complications, particularly in immunocompromised patients. In this report, we present a clinical case detailing the successful treatment of BF following an adult-toadult left lobe living donor LT (LDLT). A 61-year-old female underwent left lobe LDLT.The early postoperative period was complicated by bile leakage and biliary stricture.To address the biliary stricture, biloma evacuation and endoscopic retrograde cholangiography (ERCP) with sphincterotomy were performed. On postoperative day (POD) 2after ERCP, the patient developed a BF. Thoracostomy drainage successfully resolved the effusion within 2 weeks, during which time the diameters of the biliary ducts normalized on ultrasonography. The patient was discharged on POD 70 with normal liver graft function. Although rare, BF following LT can lead to significant complications dueto the recipient's immunosuppressed state and heightened risk of infection. Therefore,a pleural effusion persisting for more than 4 weeks after surgery should raise suspicion of BF, especially in patients with a history of early bile leakage and biliary stricture.

Background: Post-liver transplant biliary strictures are a common cause of morbidity among patients who have undergone living donor liver transplantation (LDLT). Limited data are available concerning the response rates to various treatment modalities and the long-term outcomes for these individuals. Methods: This study was a retrospective analysis of a prospectively collected database, including adult patients aged 18 years or older who underwent LDLT between 2006 and 2022. Results: Between 2006 and 2022, a total of 3,550 patients underwent liver transplantation. After applying exclusion criteria, 2,956 patients were included in the analysis.During the study period, 344 patients (11.6%) developed biliary strictures. Of these, 77.0% underwent endoscopic retrograde cholangiopancreatography as the primary treatment for biliary strictures, while the remainder received percutaneous transhepatic biliary drainage. Identified risk factors for post-liver transplant biliary strictures included the presence of multiple biliary anastomoses, bile leak, and older donor and recipient ages. The overall graft and patient survival rates were comparable between patients with and without biliary strictures, at both 1 year (93.0% vs. 96.3%) and 5 years (82.3% vs. 79.2%). Conclusions Biliary strictures are observed in approximately 11% of recipients following LDLT. While the presence of biliary strictures is associated with increased morbidity, it does not significantly impact patient survival.

Pancreatic islet transplantation represents the optimal treatment for severe hypoglycemia, a serious complication experienced by patients with long-term type 1 diabetes who are undergoing insulin therapy. However, the limited availability of donor organs restricts its widespread use. Porcine pancreatic islets could offer a viable alternative to address this organ shortage. For successful pancreatic islet xenotransplantation using porcine pancreatic islets, efficacy and safety must first be demonstrated in pig-to-nonhuman primate (NHP) preclinical studies, as outlined in the consensus statement of the International Xenotransplantation Association. Our group has achieved long-term survival of wild-type porcine islet grafts in immunosuppressed NHPs by employing two immunosuppressive protocols: one based on CD40-CD40L blockade and another utilizing clinically available immunosuppressants. A clinical trial for pancreatic islet xenotransplantation, following the latter protocol, has received approval from the Korean Ministry of Food and Drug Safety (MFDS). This review aims to highlight the results of clinical trials involving porcine islet xenotransplantation to date, along with the age-specific and other characteristics of the porcine islets used in these trials and the preclinical NHP studies that support them. It offers insights into the perspectives around the first clinical islet xenotransplantation approved by the Korean MFDS, emphasizing improved long-term graft survival.

Achieving long-term survival in pig-to-primate liver xenotransplantation has proven highly challenging due to significant hematological issues. This paper investigates the primary obstacles from a hematological perspective, focusing on coagulation disorders caused by molecular incompatibility between species. It also examines the mismatched glycan structures on the surfaces of platelets and red blood cells, which lead to sequestration and phagocytosis by recipient macrophages. These mismatches underscore the need for improved glycan and molecular compatibility to overcome im-munological and physiological barriers. Moreover, the liver's unique role in synthesizinga wide array of proteins, especially those involved in blood coagulation, introduces additional challenges of molecular incompatibility compared to other organs, such as the heart and kidneys. This study highlights the importance of addressing these challenges to improve the outcomes of liver xenotransplantation and suggests the necessity of strategies like glycan matching and the development of gene-edited pigs specifically tailored for liver transplantation.

Background: Valganciclovir (ValG) is the most widely used drug for cytomegalovirus (CMV) prophylaxis in kidney transplant recipients (KTRs). However, it is associated with dose-limiting side effects and considerable costs. Some centers have identified valacyclovir (ValA) as an economically attractive alternative with a lower risk of bone marrow suppression. The comparative effectiveness of these two drugs is not well-established.This study aims to compare the efficacy and safety of ValA and ValG for CMV prophylaxis in KTRs. Methods: Searches were conducted of the Medline, Cochrane, Web of Science, Embase, and Ovid databases. Endpoints encompassed the incidence of CMV disease, CMV viremia, acute rejection, leukopeniaeutropenia, and other infections, including BK polyomavirus and non-CMV herpesviruses (HVs). Risk ratios (RRs) with 95% confidence intervals (CIs) were pooled using a random-effects model. Results: Six studies, comprising 888 patients (438 receiving ValA), were included. The groups were comparable in CMV viremia incidence (RR, 0.70; 95% CI, 0.31–1.57; P=0.4) and the development of CMV disease (RR, 0.74; 95% CI, 0.09–5.97; P=0.8). No significant differences in acute rejection rates were observed (RR, 0.97; 95% CI, 0.50–1.91;P=0.8). However, the rate of leukopeniaeutropenia was significantly lower in the ValA group (RR, 0.57; 95% CI, 0.42–0.77; P<0.01). No significant differences were noted for BK viremia (RR, 0.67; 95% CI, 0.24–1.87; P=0.4) or other HV infections (RR, 1.43; 95% CI, 0.61–3.38; P=0.4). Conclusions The drugs demonstrate comparable efficacy in preventing CMV infection following kidney transplantation. However, ValA may have a lower impact on bone marrow suppression.

Vaccine-induced hypermetabolic lymph nodes have been clinically observed following coronavirus disease 2019 (COVID-19) mRNA vaccination. Specifically, the booster dose of the mRNA vaccines, produced by Pfizer and Moderna, has been linked to a relatively high incidence of lymphadenopathy. We present the case of a kidney transplant recipient who developed an enlarged abdominal mass after receiving a booster dose of the COVID-19 mRNA vaccine. This mass occupied the retroperitoneal space, infiltrated the psoas muscle, and resulted in ureteric compression and hydronephrosis. Percutaneous drainage and analysis of the perirenal fluid revealed the presence of lymphatic fluid. In summary, lymphadenopathy is a recognized adverse reaction to the Pfizer and Moderna vaccines. Patients with compromised immune systems should be informed about the incidence and potential severity of lymphadenopathy following booster vaccination.

Background: Kidney transplant recipients (KTRs) are at risk of coronavirus disease 2019 (COVID-19) complications and mortality. This study examined factors associated with moderate, severe, or critical COVID-19 infection among KTRs during the Omicron-predominant period. Methods: This single-center retrospective study included KTRs aged ≥18 years diag-nosed with COVID-19 between January 1, 2022, and December 31, 2023. Mild infection was defined as symptomatic illness without lower respiratory tract infection (LRTI);moderate infection as LRTI without hypoxia; severe infection as oxygen saturation <94% on room air; and critical infection as respiratory failure, septic shock, or multiple organ dysfunction. We compared the characteristics of KTRs with asymptomatic or mild COVID-19 versus those with moderate to critical disease. Logistic regression analysis was performed to identify factors associated with moderate to critical illness. Results: Most KTRs (94.4%) had received three or more vaccine doses. Of 603 episodes of COVID-19 infection during the study period, 554 (91.9%) were asymptomatic or mild, while 49 (8.1%) were moderate to critical. Multivariate analysis revealed that older age (adjusted odds ratio [aOR], 1.037; 95% confidence interval [CI], 1.006–1.069) and longer symptom duration before seeking care (aOR, 1.288; 95% CI, 1.155–1.436) were associated with higher odds of moderate to critical disease. Protective factors included receiving a vaccine booster within the past year (aOR, 0.414; 95% CI, 0.212–0.809) and higher glomerular filtration rate (aOR, 0.971; 95% CI, 0.956–0.986). Conclusions KTRs should seek care early if infected with COVID-19 and keep their COVID-19 vaccine boosters updated within 1 year of the last dose.