ABO-C Group Research Articles

Impact of Baseline Anti-ABO Antibody Titer on Biliary Complications in ABO-Incompatible Living-Donor Liver Transplantation.

Background: Although advancements in desensitization protocols have led to increased ABO-incompatible (ABOi) living-donor liver transplantation (LDLT), a higher biliary complication rate remains a problem. This study evaluated the effect of baseline anti-ABO antibody titers before desensitization on biliary complications after ABOi LDLT. Methods: The study cohort comprised 116 patients in the ABO-compatible group (ABOc), 29 in the ABOi with the low titer (<1:128) group (ABOi-L), and 14 in the high titer (≥1:128) group (ABOi-H). Results: Biliary complications occurred more frequently in the ABOi-H group than in the ABOi-L and ABOc groups (7 [50.0%] vs. 8 [27.6%] and 24 [20.7%], respectively, p = 0.041). Biliary complication-free survival was significantly worse in the ABOi-H group than in the other groups (p = 0.043). Diffuse intrahepatic biliary strictures occurred more frequently in the ABOi-H group than in the other groups (p = 0.005). Multivariable analysis revealed that the high anti-ABO antibody titer (≥1:128) is an independent risk factor for biliary complications (hazard ratio 3.943 [1.635-9.506]; p = 0.002). Conclusions: A high baseline anti-ABO antibody titer (≥1:128), female sex, and hepatic artery complications are significant risk factors for biliary complications.

Biocompatible Lysine Protecting Groups for the Chemoenzymatic Synthesis of K48/K63 Heterotypic and Branched Ubiquitin Chains.

The elucidation of emerging biological functions of heterotypic and branched ubiquitin (Ub) chains requires new strategies for their preparation with defined lengths and connectivity. While in vitro enzymatic assembly using expressed E1-activating and E2-conjugating enzymes can deliver homotypic chains, the synthesis of branched chains typically requires extensive mutations of lysines or other sequence modifications. The combination of K48- and K63-biased E2-conjugating enzymes and two new carbamate protecting groups-pyridoxal 5'-phosphate (PLP)-cleavable aminobutanamide carbamate (Abac group) and periodate-cleavable aminobutanol carbamate (Aboc group)-provides a strategy for the synthesis of heterotypic and branched Ub trimers, tetramers, and pentamers. The Abac- and Aboc-protected lysines are readily prepared and incorporated into synthetic ubiquitin monomers. As these masking groups contain a basic amine, they preserve the overall charge and properties of the Ub structure, facilitating folding and enzymatic conjugations. These protecting groups can be chemoselectively removed from folded Ub chains and monomers by buffered solutions of PLP or NaIO4. Through the incorporation of a cleavable C-terminal His-tag on the Ub acceptor, the entire process of chain building, iterative Abac deprotections, and global Aboc cleavage can be conducted on a resin support, obviating the need for handling and purification of the intermediate oligomers. Simple modulation of the Ub monomers affords various K48/K63 branched chains, including tetramers and pentamers not previously accessible by synthetic or biochemical methods.

Clinical Analysis of ABO-Incompatible Living-Donor Liver Transplantation in Children

To evaluate the safety and clinical efficacy of ABO-incompatible living-donor liver transplantation (LDLT) in children. The clinical data of 62 children who underwent for the first time living donor liver transplantation in our hospital from April 2019 to July 2020 were retrospectively analyzed. According to the blood type matching of donor and recipient, the patients were divided into 3 groups, ABO-identical (ABO-Id, n=33), ABO-compatible (ABO-C, n=10) and ABO-incompatible (ABO-In, n=19), the median age of recipients in the three groups being 5 months. In the ABO-In group, 4 recipients whose condition was combined with liver failure and 2 recipients who had blood group antibody titers≥1∶32 received preoperative plasma exchange. All ABO-incompatible recipients had preoperative blood group antibody titers<1∶32. All recipients in the three groups underwent piggyback liver transplantation and received immunosuppressive and anticoagulation therapy. Postoperative follow-up was 5 to 20 months, the median being 12 months, measured until December 31, 2020 or until the date of death. Baseline clinical data, postoperative survival, and postoperative complications of recipients in the three groups were analyzed. There were no significant differences in age, gender, underlying disease, operation history, Child Pugh score, donor age, graft to recipient weight ratio (GR/WR), cold ischemia time, warm ischemia time, duration of surgery, intraoperative blood loss and the use of immunosuppressants among the recipients in the three groups (all P>0.05). There was one death in the perioperative period and two deaths in the postoperative period in the ABO-Id group. There was one death in the postoperative period in the ABO-C group. There was one death in the perioperative period and one death in the postoperative period in the ABO-In group. There was no significant difference in the overall cumulative survival rate among the three groups ( P>0.05). There were no significant differences in the incidence of postoperative infection, acute rejection, biliary anastomotic stenosis and vascular complications among the three groups ( P>0.05). ABO-In LDLT is an effective and safe treatment option that can effectively expand the pool of live donors for liver transplantation and save the life of children with end-stage liver disease.

Outcomes of ABO-Incompatible Kidney Transplantation with Respect to Baseline Isoagglutinin Immunoglobulin G Titers

Background: ABO-incompatible kidney transplantation is one of the ways to increase the donor pool by as much as 30%–35%. Studies comparing baseline titers have shown conflicting results with respect to graft outcomes. This study attempts to evaluate the outcomes of ABO-incompatible transplant with high and low baseline immunoglobulin G (IgG) isoagglutinin titers to the outcomes of ABO compatible transplant. Materials and Methods: This was a retrospective observational study, in which 954 renal transplant recipients were included in the study. Of these, 873 patients had undergone ABO compatible kidney transplantation. Of the 81 patients who underwent an ABO-incompatible transplantation, 67 belonged to the low titer group (defined as the baseline IgG ≤ 1:64) and 14 belonged to the high titer group (defined as baseline IgG ≥ 1:128). Patients were followed up for a period of 1 year. Laboratory assessments were performed at baseline and at each visit. Graft survival, rejection episodes, patient survival, and infections were assessed on a continuous basis. Graft loss was defined by the need to return to dialysis. Results: Death censored graft survival was 92.3% in the high titer group as compared to 98.2% in ABO compatible group, but this difference was not significant (P = 0.231). Graft survival in the low titer group (96.8%) was comparable to the compatible group (P = 0.328). The proportion of patients who developed biopsy-proven rejections was lower in ABO compatible groups (6.5%) when compared to ABOi high (21.4%) and low titer groups (13.4%), respectively (P = 0.063 and 0.033, respectively). Antibody-mediated rejections were significantly fewer in ABO compatible group (1.8%) versus high titer group (21.4%) and low titer group (11.9%) (P = 0.003 and P &lt; 0.001, respectively). Patient survival was higher in ABOc group (97.9%) as compared to high (92.9%) and low titer (94.0%) groups though the difference did not achieve statistical significance. Most of the deaths were attributed to infections. Conclusion: ABO-incompatible transplantation is an acceptable treatment for those with end-stage renal disease; however, this comes with a caveat of increased risk of acute rejections and infections in patients with baseline titers of 1:128 or higher.

P1745EFFECTS OF DESENSITIZATION THERAPY ON LYMPH NODES AND PERIPHERAL BLOOD TFH AND TFR CELLS IN ABO-INCOMPATIBLE KIDNEY TRANSPLANT RECIPIENTS

Abstract Background and Aims Desensitization therapy has enabled successful transplantation of renal allografts across the ABO blood group barrier, which significantly expands the living donor pool. Whether the B cell depletion induced by rituximab would affect the proportions of peripheral blood (PB) and lymph nodes (LN) T follicular helper (Tfh) and T follicular regulatory (Tfr) cells, whose survival depends on B cells, in ABO-incompatible kidney transplant recipients (ABOi-KTRs) is unknown. Method PB and LN samples were simultaneously collected on the day of transplantation from 14 ABOi-KTRs and 12 ABO-compatible KTRs (ABOc-KTRs) between January to October 2019. Additional PB from ABOi-KTRs was obtained before desensitization treatment (Rituximab+plasmapheresis+ immunosuppression). All recipients were undergone living donor transplantation. The frequency of B, Tfh (CD4+CXCR5+Foxp3-) and Tfr (CD4+CXCR5+Foxp3+) cells and the expression the PD-1, ICOS on Tfh and Tfr cells were quantified by flow cytometry. Results After desensitization treatment, significantly lower proportions of PB and LN B cells were observed in ABOi-KTRs (ABOi-a) when compared to ABOc and ABOi-b (ABOi-KTRs before desensitization) groups (Fig. A). Circulating Tfr cells decreased significantly after desensitization therapy, while no difference was found in LN Tfr cells (Fig. F). In addition, ABOi-a group showed higher expression of PD-1 on Tfr cell within PB, but lower within LN when compared to ABOi-b and ABOc groups, respectively (Fig. G). For Tfh proportion and its expression of PD-1 and ICOS within PB and LN, no significant difference was observed among groups (Fig. B-D). Significantly lower ratio of Tfr to Tfh was observed after ABO desensitization (Fig. E). Conclusion Our results indicated that ABO desensitization had significant suppression effects on B cells both within the PB and LN of ABOi-KTRs. In addition, the desensitization treatment mainly affected circulating Tfr cells, instead of Tfh cells, which shifted the balance between Tfr and Tfh cells towards Tfr cells in PB. Whereas, this treatment showed no influence on Tfh and Tfr populations within LN in ABOi-KTRs.

P1740KINETICS OF B-CELL SUBSETS RECONSTITUTION FOLLOWING RITUXIMAB TREATMENT IN ABO-INCOMPATIBLE KIDNEY TRANSPLANT RECIPIENTS

Abstract Background and Aims With the application of B-cell-depleting agent rituximab, plasmapheresis and powerful immunosuppression, ABO-incompatible kidney transplant recipients (ABOi-KT) have successfully overcome the ABO antibody barrier. As an important immune cell population, B cells are not only involved in antibody-mediated rejection, but also have been reported to have different immunoregulatory effects due to the existence of distinct B cell subsets. Therefore, comprehensively understanding the reconstitution of B-cell subsets in ABOi-KTRs is crucial to know the immune status that may be related to the subsequent complications. Method Fresh whole blood were collected from 22 ABOi-KTRs and 22 ABO-compatible recipients (ABOc-KTRs) at 0, 1week, 2 weeks ,1month, 3months, and 6 months post-transplantation between October 2018 and May 2019. In addition, pre-desensitization samples were also collected from ABOi-KTRs. B cell subsets including total, naïve, memory, plasma, plasma blast and regulatory B cells were determined by flow cytometry. Results The percentages of B cells in ABOi group remained extremely low and significantly lower than ABOc group through the first 6 months after rituximab treatment (Fig. A). Similar trends were observed in total memory and switched memory B cells whose frequencies increased within first 2 weeks, then decreased thereafter. Meanwhile, the significant differences between ABOi and ABOc groups disappeared at 6 months (Fig. B-D). In addition, plasma and plasma blast B cells increased 2 weeks after transplantation and were significantly higher in ABOi group compared to ABOc group (Fig. E, G), while Naïve B cells started to elevate 1 month after transplantation in ABOi-KTRs and significantly higher proportions were found in ABOc group through the entire 6 months (Fig. F). No obvious difference was observed between ABOi and ABOc groups regarding unswitched memory and regulatory B cell percentages (Fig. C, H). Conclusion Our preliminary results indicated that B-cell depletion therapy applied in ABOi-KTRs not only significantly reduced the number of B cells, but also changed the composition of B cell subsets in the remaining B cell population. Whether such alteration would be clinical significance requires further follow-up.

The management and outcomes of ABO-incompatible pediatric liver transplantation: Experience of a single Chinese center

BackgroundTo investigate the safety of using ABO incompatible (ABO-i) liver grafts in pediatric patients under our prophylactic strategies. MethodsA total number of 544 pediatric liver transplantations between January 2013 and December 2017 performed in Organ Transplant Center, Tianjin First Central Hospital were included in this study. The recipients were divided into 3 groups based on the compatibility of donor-recipient blood type matching (ABO-identical group, n = 352, ABO-compatible group, n = 121 and ABO-incompatible group, n = 71). Recipient characteristics, perioperative data, postoperative complications and recipient survival rate were compared. The recipient outcomes between living-related and non-living-related ABO-incompatible liver graft recipients were also compared. ResultsThe median follow-up time in three groups were 3.4 (1.8, 6.4) years, 3.2 (1.8, 6.1) years and 2.8 (1.8, 6.2) years, without statistical difference. The cumulative 1-year and 3-year graft survival rate were 94.3% and 94.0% in ABO-id group, 93.1% and 93.1% in ABO-c group and 97.1% and 97.1% in ABO-i group. The cumulative 1-year and 3-year recipient survival rate were 96.1% and 95.5% in ABO-id group, 94.8% and 94.8% in ABO-c group and 97.1% and 97.1% in ABO-i group, respectively. No significant difference was seen among three groups. The recipient characteristics and perioperative data were similar among three groups. The recipients in ABO-i group showed significantly lower incidence of portal vein stenosis. Apart from that, three groups shared equal incidence of other surgical complications and acute rejection. Among ABO-i liver graft recipients, the cumulative 1-year and 3-year recipient survival rate were 98.2% and 98.2% in living donor liver transplant (LDLT) recipients and 92.9% and 92.9% in deceased donor liver transplant (DDLT) recipients, without significant difference. The incidence of hepatic artery thrombosis was significantly higher in DDLT group compared with LDLT group, while the other complications were similar between two groups. ConclusionOur data revealed that the application of ABO-i liver grafts in pediatric liver transplantation under rational peri-operative management strategy is a safe measure to increase donor availability for pediatric patients in Chinese population. Levels of EvidenceIII

Changes in T Cells After ABO-Incompatible Liver Transplantation

ABSTRACTPurpose: T lymphocytes are an essential component of allograft rejection and tolerance. The aims of the present study are to analyze the characteristics of T-cell subsets between ABO-incompatible living donor liver transplantation (ABO-I LDLT) and ABO-compatible LDLT (ABO-C LDLT). Materials and Methods: Between April 2013 and June 2014, 61 patients underwent adult LDLT. ABO-I LDLT patients received rituximab and all patients received basiliximab as induction therapy and tacrolimus as maintenance therapy. The distribution of peripheral blood T lymphocyte subsets pretransplant and 4, 8, 12, and 24 weeks post-transplant were serially monitored. Results: Eight patients underwent ABO-I LDLT. Patient characteristics did not vary between the ABO-I and ABO-C groups. Absolute lymphocyte counts and CD4+ T cells in the ABO-I group were lower than those in ABO-C group after LDLT (p =.034 and p =.039, respectively). However, the comparison between the ABO-I and ABO-C groups revealed that the CD8+ T cells, CD4/CD8 ratio, Vδ1 cells, Vδ2 cells, γδ T cells, Vδ1/Vδ2 ratio, CD3-CD56+ cells, and CD4+Foxp3+ T cells did not change significantly over time. Conclusions: Absolute lymphocyte counts and CD4+ T cell levels are different between ABO-I and ABO-C groups after LDLT. The present study suggests that T-cell lymphocyte changes in peripheral blood in ABO-I LDLT patients were similar to those in ABO-C LDLT patients.

Analysis of the curative effect of ABO-incompatible liver transplantation in the treatment in patients with acute severe liver disease

To analyze and evaluate the clinical effect of ABO-incompatible liver transplantation in the treatment of acute severe liver disease. A retrospective clinical study was conducted. The clinical data of 4 136 patients undergoing orthotopic liver transplantation in Organ Transplantation Center of Tianjin First Center Hospital from September 1999 to December 2013 were analyzed. The criteria of patients enrolled were as following: model for end-stage liver disease (MELD) score ≥ 20, the donor's and recipient's blood types were different, age 18-70 years, and undergone primary non-bypass orthotopic liver transplantation. According to the rate of compliance with the principles of blood transfusion, the cases were divided into two groups: ABO-compatible group (ABO-C group, n=41), ABO-incompatible group (ABO-I group, n=22). The patients in ABO-I group received basiliximab + methylprednisolone for immune induction therapy during operation, basiliximab + tacrolimus + mycophenolate + cortisol as quadruple immunosuppressive regimen after operation. They also received subcutaneous injection of low molecular heparin for anticoagulant therapy after operation, and oral warfarin or aspirin and clopidogrel bisulfate instead after 7 days. They also received routine alprostadil after operation. The remaining treatment was the same as that of ABO-C group. The clinical data, postoperative complications, rejection and survival rates of two groups were statistically analyzed. There were no significant differences in gender, age, MELD score, complicated with tumor, quality of donor liver, length of cold preservation of donor liver, duration of operation, and blood loss during operation between ABO-C and ABO-I groups. Number of splenectomy during operation was significantly higher in ABO-I group than that in ABO-C group (5 cases vs. 1 case, χ² = 4.687, P=0.030). The 3-month, 6-month, 1-year, 3-year and 5-year survival rates of ABO-C group were 89.5%, 78.3%, 72.5%, 69.1% and 61.8%, respectively, while those of ABO-I group were 78.9%, 72.9%, 65.6%, 56.2% and 46.8%, respectively. There was no significant difference in the cumulative survival rate between two groups (Log Rank, χ² = 0.647, df=1, P=0.421). The postoperative infection rate in ABO-I group was significantly higher than that of ABO-C group [63.6% (14/22) vs. 31.7% (13/41), χ² = 5.960, P=0.015]. There were no significant difference in postoperative complications of biliary tract [22.7% (5/22) vs. 12.2% (5/41), χ² = 0.531, P=0.466], vascular complications [31.8% (7/22) vs. 12.2% (5/41), χ² = 2.416, P=0.120], or rejection as diagnosed by pathology [22.7% (5/22) vs. 9.8% (4/41), χ² = 1.051, P=0.305] between ABO-I and ABO-C groups. Although ABO-incompatible liver transplantation was followed by higher postoperative infection rate and perioperative mortality, ABO-incompatible liver transplantation can still be used to save the patient with acute severe liver disease as there is a shortage of compatible donor at present.

Outcome Comparison of ABO-Incompatible Kidney Transplantation With Low-Dose Rituximab and ABO-Compatible Kidney Transplantation: A Single-Center Experience

BackgroundThe development of immunosuppressive techniques has helped overcome the ABO incompatibility barrier. However, the outcomes of ABO-incompatible (ABOi) kidney transplantation remain a controversial issue with the advent of the anti-CD20 chimeric antibody rituximab. Herein, we report the outcomes of ABOi kidney transplantation with low-dose rituximab. Patients and MethodsBetween June 2006 and April 2013, 42 patients underwent living-related kidney transplantation at our hospital. The patients were divided into 2 groups: ABO-compatible (ABOc; n = 29) and ABOi kidney transplants using low-dose rituximab (100 mg/m2) without splenectomy (n = 13). The basic immunosuppression regimen (calcineurin inhibitor [CNI], mycophenolate mofetil [MMF], and steroids) was the same for both groups, except for the use of rituximab and therapeutic apheresis in the ABOi group. We compared post-transplantation renal function, incidents of virus infection, episodes of rejection, and graft survival between the 2 groups. ResultsIn our hospital, 30% of recipients received ABOi kidney transplants. The estimated glomerular filtration rate (eGFR) did not differ between the groups. Rejection episodes confirmed by biopsy in the ABOc and ABOi groups were 8 (28%) and 4 (31%) patients (P = .833), acute antibody-mediated rejection was observed in 1 (3.5%) and 2 (15%) patients (P = .165), and virus infection was observed in 14 (48%) and 3 (23%) patients (P = .252), respectively. The 5-year patient survival rate was 100% in both groups, and the 5-year graft survival rates were 95% for ABOc and 100% for ABOi transplants (P = .527). ConclusionsThese results suggest that the outcomes of ABOi kidney transplantation with low-dose rituximab are similar to those of ABOc kidney transplantation. Further study is necessary to address the efficacy and safety of ABOi kidney transplantation.

Chronic Antibody-Mediated Rejection Is Reduced by Targeting B-Cell Immunity During an Introductory Period

Transplantation across blood group antigen and human leukocyte antigen (HLA) barriers are immunologically high risk. Both splenectomy and rituximab injection were developed to overcome those immunological barriers. The idea behind these treatments is to control B-cell immunity before and after renal transplantation and antibody production. Between January 2001 and December 2004, recipients underwent pretransplant double-filtration plasmapheresis (DFPP) and splenectomy at the time of transplantation in the ABO-incompatible group (ABO-I-SPX; n= 45). From January 2005 to June 2009, a low dose of rituximab was given as an alternative to splenectomy (ABO-I-RIT; n = 57). As a control group, we selected 83 cases of ABO-C living-donor kidney transplantation between January 2001 and December 2007 (ABO-C). We compared the graft survival rate and chronic antibody-mediated rejection (C-AMR) rate between ABO-C and ABO-I kidney transplantation with induction treatment. C-AMR rates 2 years after the operation were 8.8, 3.5 and 28.9%, and de novo donor-specific anti-HLA antibody (DSHA) positive rates were 2.2, 1.7 and 18.1% in the ABO-I-SPX, ABO-I-RIT and ABO-C groups, respectively. The ABO-C group showed the highest rate of C-AMR and de novo DSHA. B-cell depletion protocols, such as splenectomy or rituximab administration, reduced C-AMR after kidney transplantation.

Potent Immunosuppression for ABO-Incompatible Renal Transplantation May Not Be a Risk Factor for Malignancy

ABO-incompatible (ABOi) renal transplantation has been increasing, but malignant tumor is a troubling complication of kidney transplantation due to potent immunosuppression. Few previous studies, however, have demonstrated that potent immunosuppression for ABOi living-donor renal transplantation (LDRT) is a risk factor for malignancy. In the present research, data on 252 LDRT patients ftom 2003 to 2008 were retrospectively analyzed to clarify whether ABOi LDRT was associated with malignancy. A potent immunosuppressive regimen for ABOiLDRT consisted of splenectomy, cyclophosphamide, and double-filtration plasmapheresis to minimize the risk of antibody-mediated rejection, in addition to conventional immunosuppresssants including calcineurin inhibitor, prednisolone, and anti-CD25 monoclonal antibody. A total of 11 incidences of malignancy were observed during a median follow-up of 48 months. The incidence rates in ABO-compatible (ABOc; n = 189) and ABOi (n = 63) LDRT groups were 4.2 % (8/189) and 4.8 % (3/63), respectively. Kaplan-Meier survival analysis showed no statistical difference in event-free survival for malignancy between ABOc and ABOiLDRT groups (log-rank P = .73). Multivariable Cox regression analyses identified no associations of malignancy with ABOi LDRT or any immunosuppressant use. In conclusion, our investigation suggested that potent immunosuppression with splenectomy and cyclophosphamide for ABOi LDRT may not be a risk fietor for malignancy.

Clinical efficacies of ABO-incompatible adult liver transplantation

To evaluate the efficacy and safety of ABO-incompatible liver transplantation in adult patients with fulminant hepatitis B. The clinical data of 97 cases of adult liver transplantation for fulminant hepatitis B were retrospectively analyzed. The patients were grouped as ABO-identical (ABO-Id, n = 58), ABO-compatible (ABO-C, n = 19) and ABO-incompatible (ABO-In, n = 20). The rates of rejection, infection, biliary tract complications, vascular complications, and patient and graft survivals were compared among 3 groups. The 3-month, 1-year and 3-year graft survival rates were 87.9%/77.6%/65.3% in ABO-Id group, 84.2%/73.7%/66.5% in ABO-C group and 50.0%/35.0%/33.3% in ABO-In group respectively. There were significant differences between ABO-Id and ABO-In (P < 0.05). The incidences of rejection, infection, vascular complications and biliary tract complications were 8.6%, 20.7%, 3.4% and 6.9% in ABO-Id group, 35%, 60%, 20% and 30% in ABO-In group (P < 0.05) and 10.5%, 26.3%, 5.3% and 10.5% respectively in ABO-C group (P > 0.05). ABO-C liver transplantation is an important therapeutic option in adult patients with acute liver failure awaiting an emergency procedure. ABO-In transplantation can be used only for life-rescuing in patients with fulminant hepatitis since it is associated with a higher risk of rejection, infection, vascular thrombosis, ischemic bile duct complications and poor patient and graft survival.

Pediatric patients receiving ABO-incompatible living related liver transplantation exhibit higher serum transforming growth factor-β1, interferon-γ and interleukin-2 levels

ABO-incompatible liver transplantation (LTx) is becoming more common in response to the paucity of liver allografts. Several studies have expressed concern about the effect of ABO compatibility on graft survival. To evaluate the differences in serum cytokine levels between ABO-incompatible (ABO-i) and ABO-compatible (ABO-c; includes ABO-compatible and identical) pediatric LTx recipients during regular outpatient follow-up. Note that, in the field of organ transplantation, transplants are categorized as incompatible, compatible or identical; accordingly, these are the terms we use in the paper. A clinical outpatient study measuring serum transforming growth factor (TGF)-β1, interferon (IFN)-γ, interleukin (IL)-2 and IL-10 in 43 living related liver transplantation (LRLT) recipients, of whom 36 received ABO-c LRLT (34 were ABO-identical and 2 were non-identical) and 7 ABO-i LRLT. Serum glutamic pyruvic transaminase, glutamic oxaloacetic transaminase, gamma-glutamyl transpeptidase, alkaline phosphatase, lactate dehydrogenase and bilirubin were measured as part of the patients' regular follow-up visits. There were no differences between the ABO-c and ABO-i groups in terms of recipient's age [mean 12.6 vs. 11.1years (y)], post-LTx duration (mean 7.3 vs. 7.3y), donor's age (mean 35.5 vs. 34.6y), body weight (28.9±2.9 vs. 27.9±6.9kg), or gender (19 female and 17 male vs. 4 female and 3 male). Serum TGF-β1, IFN-γ and IL-2 were significantly higher in the ABO-i group than in the ABO-c group. IL-10, however, did not differ between the two groups. There was a tendency toward higher γGTP levels in the ABO-i group, but this difference did not reach significance. ABO-incompatible LRLTx patients have higher serum TGF-β1, IFN-γ and IL-2 levels as measured at regular outpatient visits. As a result, they face a higher risk of T-helper 1 cell polarization, which could make graft rejection more likely.