Passenger lymphocyte syndrome (PLS) is most commonly observed after solid organ transplantation with minor ABO blood group incompatibility. It consists of a set of clinical symptoms brought on by the remaining lymphocytes of the donor organ developing antibodies against the recipient\'s antigens. Here, we describe a typical case of PLS in a type A+ recipient receiving a liver transplant from a type O+ donor. She suffered from jaundice, abnormally decreased hemoglobin level, and severe hemolytic anemia without bleeding. During hemolysis, we detected a positive direct antiglobulin test (DAT), and the thermal elution test revealed the presence of IgG anti-A antibodies in her serum. When immunosuppressive agents and blood transfusion were used together, cross-matched O+ washing red blood cells led to an expected outcome without side effects.

BACKGROUND: Liver transplantation (LT) is a unique and effective method for treating end-stage liver diseases and acute liver failure, bringing hope to many patients with liver cancer. LT is currently widely used in the treatment of liver diseases. However, there have been no patients with liver cancer who have undergone ABO-incompatible (ABOi) LT after treatment with the programmed cell death protein 1 (PD-1) inhibitor reported in the literature.
METHODS: A patient with liver cancer who received sintilimab injection, an anti-PD1 therapy, before LT was admitted in the transplantation centre. This patient underwent ABOi LT. The perioperative treatment strategy of this patient was reported. A desensitisation protocol was conducted urgently for the patient before operation, and the immunosuppression programme of LT was adjusted. After operation, isoagglutinin titer and liver function indicators were strictly monitored. The patient recovered well after operation, and no sign of rejection reaction was observed.
CONCLUSIONS: We reported a patient with hepatocellular carcinoma (HCC) who received PD-1 inhibitor treatment before operation and successfully underwent ABOi LT. The present case report provides novel insights into the perioperative management of utilizing PD-1 inhibitors prior to ABOi LT in patients diagnosed with hepatocellular carcinoma (HCC).

UNASSIGNED: With the improvement of immunosuppressive regimens, the success rate and availability of ABO-incompatible (ABO-i) kidney transplantation (KT) have gradually increased. However, the management of immunosuppression protocols and complications associated with ABO-i KT is complex. Here, we report a clinical case of ABO-i living donor KT with allograft dysfunction caused by acute blood group antibody-dependent rejection triggered by human parvovirus B19 (B19V).
UNASSIGNED: The ABO blood group of the recipient was O, and that of the donor was B. The recipient had high baseline anti-B antibody titers (IgM, 1:1024; IgG, 1:64). Before transplantation, he completed a desensitization protocol comprising plasma exchange, double-filtration plasmapheresis, and rituximab, which maintained a low blood group antibody level and resulted in successful transplantation. Two weeks after surgery, the recipient developed a B19V infection combined with acute T-cell-mediated rejection. After the anti-rejection regimen, acute rejection (AR) was successfully reversed, but B19V persisted. One week after AR stabilization, the patient experienced acute antibody-mediated rejection that was more severe and refractory, resulting in the loss of the transplanted kidney.
UNASSIGNED: Desensitization combined with immunosuppressants can lead to overimmunosuppression and cause various infections. Infections could break the accommodation state of the patient, thereby inducing AR and resulting in the loss of the transplanted kidney.

Background: ABO-incompatible liver transplantation (ABOi LT) under the desensitization protocol with rituximab had excellent survival outcomes comparable to those of ABO-compatible liver transplantation (ABOc LT). In this work, we explored the effect of ABOi LT on recipients from the perspective of biliary microbiota and metabonomics. Methods: Liver transplant (LT) recipients treated at our center were enrolled in the study. In total, 6 ABOi LT recipients and 12 ABOc LT recipients were enrolled, and we collected their bile five times (during LT and at 2 days, 1 week, 2 weeks and 1 month after LT). The collected samples were used for 16S ribosomal RNA sequencing and liquid chromatography mass spectrometry analysis. Results: We obtained 90 bile samples. Whether in group ABOi LT or ABOc LT, the most common phyla in all of the samples were Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria. The most common genera were Lactobacillus, Weissella, Klebsiella, Pantoea and Lactococcus. There was no significant difference in the diversity between the two groups at 1 week, 2 weeks and 1 month after LT. However, the biggest disparities between the ABOi LT recipients and ABOc LT recipients were observed 2 days after LT, including increased biodiversity with a higher ACE, Chao1, OBS and Shannon index (p < 0.05), and more Staphylococcus in ABOi LT and binary−Jaccard dissimilarity, which indicated varying β-diversity (p = 0.046). These differences were not observed at 1 week, 2 weeks and 1 month after LT. The principal coordinate analysis (PCoA) revealed that the composition of the bile microbiota did not change significantly within 1 month after LT by longitudinal comparison. In an analysis of the bile components, the metabolites were not significantly different every time. However, four enrichment KEGG pathways were observed among the groups. Conclusion: These findings suggest that ABOi LT under the desensitization protocol with rituximab did not significantly affect the biliary microbiota and metabolites of recipients.

BACKGROUND: ABO incompatibility is not a contraindication but would affect the prognosis of allogeneic hematopoietic stem cell transplantation (allo-HSCT). The dynamic change of blood phenotype is not only related to the patient\'s status, but also the basis for the implementation of compatible blood transfusion. The criteria for judging a complete transformation to donor-type and the principle of blood transfusion at relapse need to be unified. We aimed to illustrate the significance of blood group monitoring after allo-HSCT.
METHODS: We collected 263 patients underwent ABO incompatible allo-HSCT from January 2010 to December 2019, and monitored blood type regularly according to the frequency of the patient\'s return visits till complete conversion or death. Non-parametric test was used to find differences among incompatible groups. We analyzed factors potentially influence blood type conversion by Binary Logistic model. Cox regression model was used to illustrate the relationship between blood-type conversion and prognosis.
RESULTS: The median days of conversion were 107, 91 and 108 in major-, minor- and bidirectional groups respectively. Blood type conversion correlated with HLA compatibility (P = 0.012, OR=2.69) and acute graft-versus-host-disease (P = 0.001, OR=0.06). Patients with incomplete blood type conversion had a higher death rate than those with complete blood type conversion(P = 0.003, OR=3.703).
CONCLUSIONS: Blood type monitoring can help to evaluate the prognosis of transplantation and assess the risk of death. It is recommended to monitor the changes of blood group antigens and antibodies, especially within a year after transplantation, to predict the risk of adverse events (such as GVHD, recurrence, death, etc.).

ABO blood group antibodies have not been generated or are at low titer during early infancy. Therefore, in theory, ABO-incompatible kidney transplantation (ABOi KT) may be successfully achieved in small infants without any pre-transplant treatment. We report here the first ABO-incompatible deceased donor kidney transplantation (ABOi DDKT) in an infant. The recipient infant was ABO blood group O, and the donor group A. The recipient was diagnosed with a Wilms tumor gene 1 (WT1) mutation and had received peritoneal dialysis for 4 months prior to transplant. At 7 months and 27 days of age, the infant underwent bilateral native nephrectomy and single-kidney transplantation from a 3-year-old brain-dead donor. No pre- or post-transplantation antibody removal treatment was performed, since the recipient\'s anti-iso-hemagglutinin-A Ig-M/G antibody titers were both low (1:2) before transplantation and have remained at low levels or undetectable to date. At 11 months post-transplant, the recipient is at home, thriving, with normal development and graft function. This outcome suggests that ABOi DDKT without antibody removal preparatory treatment is feasible in small infants, providing a new option for kidney transplantation in this age range.

ABO incompatibility is common in hematopoietic stem cell transplantation (HSCT); however, the impact of donor-recipient ABO compatibility on transplantation outcomes in different HSCT settings is controversial. Moreover, haploidentical stem cell transplantation (haplo-SCT) with peripheral blood stem cell (PBSC)-derived grafts has not been well investigated. The present study aimed to investigate the impact of ABO incompatibility on post-transplantation outcomes, engraftment kinetics, blood product requirements, transfusion independence, and the incidence of poor graft function (PGF) in antithymocyte globulin (ATG)-based haplo-SCT with PBSC grafts during long-term follow-up. We prospectively evaluated 510 patients with hematologic malignancies who underwent haplo-SCT after myeloablative conditioning (MAC). The primary endpoint was overall survival (OS), and secondary endpoints were nonrelapse mortality (NRM), graft-versus-host disease (GVHD), relapse, neutrophil and platelet engraftment, blood transfusion requirements, transfusion independence, and the incidence of PGF. There was no significant association between ABO matching and OS, disease-free survival (DFS), relapse, NRM, grade II-IV acute GVHD, grade III-IV acute GVHD, and moderate and severe chronic GVHD. There were also no significant differences in neutrophil and platelet engraftment, blood transfusion independence, and transfusion requirements at 30, 60, 90, 180, and 365 days post-transplantation among patients with ABO matching and those with minor, major, or bidirectional ABO incompatibility. Donor-recipient ABO matching did not differ significantly according to graft function (good versus poor). ABO incompatibility status has no major impact on patient outcomes in patients with hematologic malignancies undergoing ATG-based MAC haplo-SCT with PBSC-derived grafts.

Maternal IgG anti-A/B titers have been considered as a susceptible factor to the risk of ABO hemolytic disease in newborn (ABO-HDN). However, the results remain controversial. This meta-analysis aimed to estimate the association between maternal IgG anti-A/B titers and the risk of ABO-HDN.
METHODS: Trials on the relationship between maternal IgG anti-A/B titers and the risk of ABO-HDN were collected by searching Embase, PubMed, and Cochrane Central Register of Controlled Trials (CENTRAL) electronic databases. The inclusion criteria were maternal IgG anti-A/B titers screening and the evaluation of clinical outcomes in relation to ABO-HDN. Stata 12.0 was used to analyze the data.
RESULTS: A total of 23 trials were eligible for inclusion, of which four trials with 5,246 participants were suitable for this meta-analysis. Meta-analysis results suggested that maternal IgG anti-A/B titers were significantly associated with the risk of ABO-HDN [OR = 2.86, 95% CI = 2.50-3.28; OR = 4.67, 95% CI = 3.92-5.55; OR = 1.61, 95% CI = 1.36-1.91 in titers (128 to 256) vs. titers (64 or lower), titers (512 or higher) vs. titers (64 or lower), and titers (512 or higher) vs. titers (128-256), respectively].
CONCLUSIONS: Our meta-analysis suggests that maternal IgG anti-A/B titers are significantly associated with the risk of ABO-HDN. They contribute to the prediction of risk of ABO-HDN, in addition to the need for invasive treatment for antibody titers ≥512.

ABO-incompatible intestinal transplantation has rarely been performed due to poor patient outcomes. Herein we present a case of successful ABO-incompatible intestinal transplantation with a 2-year follow-up. A 16-year-old female with a history of extensive bowel resection received an ABO-incompatible living donor bowel graft from her father (blood type AB graft into a type A recipient). Posttransplant immunosuppression consisted of an initial anti-CD20, plasmapheresis/intravenous immunoglobulin before transplantation, followed by an anti-thymocyte globulin (ATG) induction and splenectomy, and maintenance with tacrolimus and prednisone. Her postoperative course was remarkable for a single episode of rejection on day 14 which responded promptly to treatment with methyprednisolone and ATG. Three months after transplantation, the patient developed an abdominal abscess requiring open surgical drainage. No viral infections were encountered. Posttransplant anti-B antibody titers and anti-B7 donor-specific antibody levels remained low. At a 2-year follow-up, the patient showed a progressive weight gain of 5.0 kg. This case illustrates that ABO-incompatible living-related bowel transplantation is immunologically feasible and is associated with good outcomes for the recipient. The management of blood type antibodies and the use of adequate immunosuppression in the early period of the procedure may be the keys to the success of future cases.