Significance of semiquantitative assessment of preformed donor-specific antibody using luminex single bead assay in living related liver transplantation

Clinical Outcomes of Administration of Rituximab for Desensitization in Liver Transplant Patients with Preformed Donor-Specific Antibodies: A Single-Center Experience

BACKGROUND The management and fate of liver transplant (LT) recipients with preformed donor-specific antibodies (pDSA) remain controversial. The aim of this study was to evaluate the clinical impact of rituximab desensitization on pDSA in LT recipients. MATERIAL AND METHODS This retrospective observational study enrolled 120 LT patients aged ≥18 years. Patients with pDSA were administered 500 mg/body rituximab 1-21 days before LT, except for those who had an active infection or had insufficient time to receive rituximab. We allocated patients to groups with or without pDSA, and then divided patients with pDSA into rituximab (+) and rituximab (-) groups for further analysis. RESULTS Twenty-three patients (19.2%) with pDSA were identified. Of these, 18 received rituximab and 5 did not receive rituximab. No patients developed adverse events related to rituximab. In both groups, the levels of pDSA class I in all patients were decreased immediately after LT, whereas those of pDSA class II decreased slowly. There were no significant differences in pathology findings and overall survival between patients with pDSA who were rituximab (+) or rituximab (-), and between patients with or without pDSA. CONCLUSIONS Rituximab desensitization for LT patients with pDSA was managed successfully without significant complications. Due to the small sample size, we could not demonstrate the benefit of rituximab desensitization for LT patients compared with the rituximab (-) group. Additionally, clinical outcomes in patients with pDSA, with or without rituximab, were similar to those without pDSA. Rituximab desensitization might be not essential for LT.

Long-term survival from progressive multifocal leukoencephalopathy in living-donor liver transplant recipient with preformed donor-specific antibody

Intensive immunosuppression has enabled liver transplantation even in recipients with preformed donor-specific antibodies (DSA), an independent risk factor for graft rejection. However, these recipients may also be at high risk of progressive multifocal encephalopathy (PML) due to the comorbid immunosuppressed status. A 58-year-old woman presented with self-limited focal-to-bilateral tonic-clonic seizures 9 months after liver transplantation. She was desensitized using rituximab and plasma exchange before transplantation and was subsequently treated with steroids, tacrolimus, and everolimus after transplantation for her preformed DSA. Neurological examination revealed mild acalculia and agraphia. Cranial MRI showed asymmetric, cortex-sparing white matter lesions that increased over a week in the left frontal, left parietal, and right parieto-occipital lobes. Polymerase chain reaction (PCR) of the cerebrospinal fluid for the JC supported the diagnosis of PML. Immune reconstitution by reducing the immunosuppressant dose stopped lesion expansion, and PCR of the cerebrospinal fluid for the JC virus became negative. Graft rejection occurred 2 months after immune reconstitution, requiring readjustment of immunosuppressants. Forty-eight months after PML onset, the patient lived at home without disabling deficits. Intensive immunosuppression may predispose recipients to PML after liver transplantation with preformed DSA. Early immune reconstitution and careful monitoring of graft rejection may help improve outcomes.

Living Donor Liver Transplantation in Patients with Preformed Donor-Specific Anti-Human Leukocyte Antigen Antibodies Using Preoperative Desensitization Therapy According to Intensity of Donor-Specific Antibodies: A Single-Center Study

BACKGROUND In liver transplantation (LT), preoperative desensitization therapy is considered necessary in patients positive for donor-specific anti-human leukocyte antigen antibodies (DSAs). However, the relationship between DSA intensity and the necessary desensitization therapy is unclear. MATERIAL AND METHODS A total of 37 adult living donor (LD) LTs performed between January 2016 and March 2022 were examined. Mycophenolate mofetil (MMF) was administered preoperatively in DSA-positive cases with positive lymphocyte cross-matching who underwent LDLT. In those with strongly positive DSA (mean fluorescence intensity 10 000), rituximab was administered 2 weeks before LDLT in addition to MMF. Cross-reactive epitope group antigen (CREG)-alone-positive cases were also treated with preoperative MMF when lymphocyte cross-matching was positive. RESULTS Of the 37 patients, 9 were DSA-positive, 7 were CREG-alone-positive, and the others were double-negative. Of 9 DSA-positive cases, desensitization therapy was performed in 7, among which rituximab administration was performed in 3 strongly DSA-positive cases. Of 7 CREG-alone-positive cases, 2 were lymphocyte cross-match-positive and underwent desensitization therapy. The 1-year survival rate was 100% in both DSA- and CREG-alone-positive cases. The frequency of T-cell mediated rejection in DSA-positive, CREG-alone-positive, and double-negative cases was 22%, 43%, and 29%, respectively, with no significant difference. Antibody-mediated rejection occurred in only 1 patient, who was strongly DSA-positive and blood-group incompatible. There was also no significant difference among the 3 groups in terms of the frequency of biliary complications or 90-day mortality. CONCLUSIONS Satisfactory LDLT results were achieved in DSA- and CREG-alone-positive cases following desensitization therapy.

Risk factors for antibody-mediated rejection in ABO blood-type incompatible and donor-specific antibody-positive liver transplantation

Antibody-mediated rejection (AMR) is a refractory rejection after ABO blood-type incompatible (ABOi) or donor-specific antibody (DSA)-positive liver transplantation (LT). Pretransplant rituximab desensitization dramatically reduced posttransplant AMR development; however, risk factors for AMR in the rituximab era remain unclear in both ABOi living-donor LT (ABOi-LDLT) and preformed DSA-positive LT (pDSA-LT). Of our 596 adult LDLTs (≥18 y) after rituximab introduction (2004-2019), 136 were ABOi-LDLT (22.8%). After excluding retransplants (9), acute liver failure (7), and protocol deviations (16), 104 ABOi-LDLTs were finally enrolled. Of these, 19 recipients developed AMR, 18 of which occurred within 2 weeks after transplantation (95%). ABOi-AMR significantly worsened graft and recipient survival than those without ( p =0.02 and 0.04, respectively). Model for End-stage Liver Disease (MELD) ≤13 (OR: 5.15 [1.63-16.3], p =0.005) and pre-rituximab anti-ABO IgM-titer ≥128 (OR: 3.25 [1.05-10.0], p =0.03) were identified as independent risk factors for ABOi-AMR development. Recipients fulfilling both factors showed significantly worse survival rates than those who did not ( p =0.003). Of 352 adult LTs, after introducing the LABScreen Single Ag method (2009-2019), pDSA with mean fluorescence intensity (MFI) ≥500 was detected in 50 cases (14.2%). After excluding 10 ABOi-LDLTs, 40 pDSA-LTs were finally analyzed, of which 5 developed AMR. The combination of high-titer (sum-MFI ≥10,000) and multi-loci pDSAs was a significant risk factor for pDSA-AMR development ( p <0.001); however, it did not affect the 5-year recipient survival compared with those without ( p =0.56). In conclusion, preoperative MELD ≤13 and pre-rituximab anti-ABO IgM-titer ≥128 for ABOi-LDLT, and the combination of sum-MFI ≥10,000 and multi-loci pDSAs for pDSA-LT, are risk factors for AMR in the era of rituximab desensitization. Characteristically, ABOi-AMR significantly deteriorated graft and recipient survival, whereas pDSA-AMR did not.

Clinical recommendations for posttransplant assessment of anti-HLA (Human Leukocyte Antigen) donor-specific antibodies: A Sensitization in Transplantation: Assessment of Risk consensus document

Although anti-HLA (Human Leukocyte Antigen) donor-specific antibodies (DSAs) are commonly measured in clinical practice and their relationship with transplant outcome is well established, clinical recommendations for anti-HLA antibody assessment are sparse. Supported by a careful and critical review of the current literature performed by the Sensitization in Transplantation: Assessment of Risk 2022 working group, this consensus report provides clinical practice recommendations in kidney, heart, lung, and liver transplantation based on expert assessment of quality and strength of evidence. The recommendations address 3 major clinical problems in transplantation and include guidance regarding posttransplant DSA assessment and application to diagnostics, prognostics, and therapeutics: (1) the clinical implications of positive posttransplant DSA detection according to DSA status (ie, preformed or de novo), (2) the relevance of posttransplant DSA assessment for precision diagnosis of antibody-mediated rejection and for treatment management, and (3) the relevance of posttransplant DSA for allograft prognosis and risk stratification. This consensus report also highlights gaps in current knowledge and provides directions for clinical investigations and trials in the future that will further refine the clinical utility of posttransplant DSA assessment, leading to improved transplant management and patient care.

The efficacy of rituximab treatment for antibody-mediated rejection in liver transplantation: A retrospective Japanese nationwide study

AIM

Antibody-mediated rejection (AMR) has been consistently elucidated in liver transplantation (LT); however, the treatment for AMR, including rituximab, has not been indicated as a strongly recommended therapeutic protocol.

METHODS

This study was conducted as the Japanese multicenter retrospective study to accumulate data on the use of rituximab for AMR among patients undergoing LT between August 2001 and December 2016. Thirteen patients (five children and eight adults) were enrolled.

RESULTS

The types of AMR in the pediatric cases were chronic AMR in four cases and indeterminate AMR in one case. Among the pediatric cases, rituximab treatment only showed therapeutic efficacy in two patients with chronic AMR. Among the adult patients, five patients had chronic AMR, and three had acute AMR. Although two patients with chronic AMR died due to graft failure, liver function tests revealed improvement after rituximab treatment in the other patients. Two of the three patients with acute AMR died due to graft failure; rituximab treatment showed no therapeutic efficacy in these cases. Although bacterial infections occurred within 3 months after rituximab administration in three patients, rituximab treatment could be safely administered without any direct adverse effects.

CONCLUSIONS

The indication of rituximab therapy as an additional treatment for mild acute AMR and chronic AMR may be feasible; however, a prospective randomized control study is needed to evaluate the therapeutic efficacy of rituximab treatment for AMR.

Rituximab Desensitization in Liver Transplant Recipients With Preformed Donor-specific HLA Antibodies: A Japanese Nationwide Survey

Background.

The significance of preformed donor-specific anti-HLA antibodies (DSAs) in liver transplant recipients is controversial. Moreover, there has been no established desensitization protocol for DSA-positive recipients.

Methods.

A Japanese nationwide survey was performed to investigate the clinical practice among preformed DSA-positive patients with special reference to rituximab desensitization.

Results.

There was a total of 47 cases, including 2 pediatric cases, in which rituximab (287 ± 159 mg [319 (50–916)/m²]) was administered to desensitize preformed DSA. The decision for the indication of rituximab desensitization was based on a single-antigen assay in the majority of cases (83%, 39/47), and the most frequent protocol was rituximab monotherapy (n = 12) followed by quadruple treatment with rituximab tacrolimus, mycophenolate mofetil, and plasmapheresis (n = 11). The overall 1-, 3-, and 5-y graft and patient survival rates among adult patients were 85%, 83%, 83%, and 81%, 77%, 74%, respectively, while neither graft loss nor death was observed in the 2 pediatric cases. The 1-, 3-, and 12-mo cumulative incidence of antibody-mediated rejection (AMR) was 11%, 13%, and 13%, respectively. The incidence of AMR was significantly higher in the lower rituximab dose group than in the higher rituximab dose group (cutoff 300 mg/m², 4% versus 24%, P = 0.041). The rate of infusion-related adverse drug reactions (ADRs) was 4.4%, and all ADRs were mild and self-limiting. A total of 99 ADRs among 27 patients were reported, none of which were severe adverse events associated with rituximab.

Conclusions.

The rituximab induction was well tolerated among DSA-positive liver transplant recipients with a satisfactory outcome. A rituximab dose >300 mg/m² was observed to achieve less incidence of the development of AMR.

Clinical relevance of donor-specific human leukocyte antigen antibodies after pediatric liver transplantation

Donor-specific human leukocyte antigen (HLA) antibodies (DSAs) have a significant role in graft survival after pediatric liver transplantation. To understand the significance of DSAs, a retrospective cohort study of 48 pediatric liver transplant recipients with posttransplant serum samples that were analyzed for DSAs was performed. According to their test results, the recipients were divided into a DSA-positive group and a DSA-negative group. Postoperative liver transplantation biopsies were performed in patients with abnormal liver function. The liver condition and prognosis of the recipients were recorded, and their association was analyzed. A total of 48 recipients were followed up for 2.7±0.8 years. DSA positivity was detected in 10 cases (20.8%). One case was positive for HLA class I and HLA class II antibodies, whereas 9 cases were positive for HLA class II antibodies, and the gene loci were HLA-DR and/or DQ. Antibody-mediated rejection (AMR) occurred in four of 10 patients in the DSA-positive group. Liver function was abnormal in 3 of 38 cases in the DSA-negative group. Multivariate analysis revealed that DSA positivity was an independent risk factor for liver insufficiency and long-term survival of recipients. In addition, Kaplan-Meier survival analysis demonstrated that there were significant differences in the survival of graft recipients between the DSA-positive group and the DSA-negative group (P<0.05). The positivity of DSAs after pediatric liver transplantation was closely related to the occurrence of AMR. These results suggested that DSAs should be routinely monitored post-operatively, and that DSA-positive recipients should be screened as soon as possible and given appropriate treatment.

Preformed donor-specific antibodies are associated with 90-day mortality in living-donor liver transplantation

AIM

The impact of donor-specific anti-human leukocyte antigen (HLA) antibodies (DSAs) on living donor liver transplantation (LDLT) is unclear. The aim of this study was to investigate the association between DSAs and short-term outcomes in LDLT recipients, and to clarify the clinical impact of DSAs.

METHOD

Anti-HLA antibodies were screened in preoperative serum samples taken from 40 liver transplant recipients at Ehime University (Toon, Japan) between August 2001 and July 2015. Screening was carried out using the Flow-PRA method, and DSAs were detected in anti-HLA antibody-positive recipients using the Luminex single-antigen identification test. A mean fluorescence intensity of 1000 was used as the cut-off for positivity. We retrospectively reviewed the clinical courses of patients who were DSA-positive to elucidate early clinical manifestations in LDLT recipients.

RESULTS

Fifteen (12 female and 3 male) patients (38%) had anti-HLA antibodies. Eight of the 15 anti-HLA antibody-positive patients were positive for DSAs, and all were women. The 90-day survival rate of DSA-positive patients (50%) was significantly lower than that of DSA-negative patients (84.4%) (0.0112; Wilcoxon test). On univariate analysis, the DSA-positive rate was significantly higher in the 90-day mortality group. Postoperatively, the incidence of acute cellular rejection was higher in DSA-positive than DSA-negative patients. Thrombotic microangiopathy developed only in DSA-positive patients. We found no relationship between DSA status and bile duct stricture.

CONCLUSION

Preformed DSAs could be associated with elevated 90-day mortality in LDLT recipients. Further large-scale studies are required to verify the risk associated with DSAs in LDLT.

Impact of Antibodies That React With Liver Tissue and Donor-Specific Anti-HLA Antibodies in Pediatric Idiopathic Posttransplantation Hepatitis

Background

The cause of late graft dysfunction has not been elucidated. Although an antibody-mediated reaction is suspected as a potential mechanism, the target antigens have not been clarified.

Methods

To clarify the etiology of idiopathic posttransplantation hepatitis (IPTH), we simultaneously examined the presence of antibodies that react with liver tissue (ARLT) by means of indirect immunofluorescence staining, as well as the presence of donor-specific anti-human leukocyte antigen antibodies (HLA-DSA). A subanalysis of the IPTH group was also performed. Within the IPTH group, the correlation between ARLT titer and clinical data were analyzed.

Results

In the sera of patients with IPTH (30 patients), ARLT were found at a significantly higher frequency than in patients without IPTH (42 patients; P < 0.001). Moreover, the ARLT titer appeared to be correlated with the severity of hepatitis or hepatic injury. In contrast, the frequency of HLA-DSA was significantly lower in patients with IPTH than in patients without IPTH (P = 0.001).

Conclusion

Our findings indicate that ARLT, and not HLA-DSA, profoundly influence the etiology of IPTH.

The authors show that antibodies that react with liver tissue and not donor-specific anti-human leukocyte antigen antibodies, profoundly influence the etiology of idiopathic posttransplantation hepatitis in children providing a rationale for therapy.

Practical Recommendations for Long-term Management of Modifiable Risks in Kidney and Liver Transplant Recipients: A Guidance Report and Clinical Checklist by the Consensus on Managing Modifiable Risk in Transplantation (COMMIT) Group

Short-term patient and graft outcomes continue to improve after kidney and liver transplantation, with 1-year survival rates over 80%; however, improving longer-term outcomes remains a challenge. Improving the function of grafts and health of recipients would not only enhance quality and length of life, but would also reduce the need for retransplantation, and thus increase the number of organs available for transplant. The clinical transplant community needs to identify and manage those patient modifiable factors, to decrease the risk of graft failure, and improve longer-term outcomes.COMMIT was formed in 2015 and is composed of 20 leading kidney and liver transplant specialists from 9 countries across Europe. The group's remit is to provide expert guidance for the long-term management of kidney and liver transplant patients, with the aim of improving outcomes by minimizing modifiable risks associated with poor graft and patient survival posttransplant.The objective of this supplement is to provide specific, practical recommendations, through the discussion of current evidence and best practice, for the management of modifiable risks in those kidney and liver transplant patients who have survived the first postoperative year. In addition, the provision of a checklist increases the clinical utility and accessibility of these recommendations, by offering a systematic and efficient way to implement screening and monitoring of modifiable risks in the clinical setting.

Donor-Specific HLA Antibodies in Living Versus Deceased Donor Liver Transplant Recipients

With less ischemia, improved donor selection and controlled procedures, living donor liver transplantation (LDLT) might lead to less HLA donor-specific antibody (DSA) formation or fewer adverse outcomes than deceased donor liver transplantation (DDLT). Using the multicenter A2ALL (Adult-to-Adult Living Donor Liver Transplantation Cohort Study) biorepository, we compared the incidence and outcomes of preformed and de novo DSAs between LDLT and DDLT. In total, 129 LDLT and 66 DDLT recipients were identified as having serial samples. The prevalence of preformed and de novo DSAs was not different between DDLT and LDLT recipients (p = 0.93). There was no association between patient survival and the timing (preformed vs. de novo), class (I vs. II) and relative levels of DSA between the groups; however, preformed DSA was associated with higher graft failure only in DDLT recipients (p = 0.01). De novo DSA was associated with graft failure regardless of liver transplant type (p = 0.005) but with rejection only in DDLT (p = 0.0001). On multivariate analysis, DSA was an independent risk factor for graft failure regardless of liver transplant type (p = 0.017, preformed; p = 0.002, de novo). In conclusion, although similar in prevalence, DSA may have more impact in DDLT than LDLT recipients. Although our findings need further validation, future research should more robustly test the effect of donor type and strategies to mitigate the impact of DSA.

The Statistical Value of Raw Fluorescence Signal in Luminex xMAP Based Multiplex Immunoassays

Tissue samples (plasma, saliva, serum or urine) from 169 patients classified as either normal or having one of seven possible diseases are analysed across three 96-well plates for the presences of 37 analytes using cytokine inflammation multiplexed immunoassay panels. Censoring for concentration data caused problems for analysis of the low abundant analytes. Using fluorescence analysis over concentration based analysis allowed analysis of these low abundant analytes. Mixed-effects analysis on the resulting fluorescence and concentration responses reveals a combination of censoring and mapping the fluorescence responses to concentration values, through a 5PL curve, changed observed analyte concentrations. Simulation verifies this, by showing a dependence on the mean florescence response and its distribution on the observed analyte concentration levels. Differences from normality, in the fluorescence responses, can lead to differences in concentration estimates and unreliable probabilities for treatment effects. It is seen that when fluorescence responses are normally distributed, probabilities of treatment effects for fluorescence based t-tests has greater statistical power than the same probabilities from concentration based t-tests. We add evidence that the fluorescence response, unlike concentration values, doesn’t require censoring and we show with respect to differential analysis on the fluorescence responses that background correction is not required.

Long-Term Outcomes of Living-Donor Liver Transplantation for Primary Biliary Cirrhosis: A Japanese Multicenter Study

The factors that influence long-term outcomes after living-donor liver transplantation (LDLT) for primary biliary cirrhosis (PBC) are not well known. Compared with deceased-donor transplantation, LDLT has an increased likelihood of a related donor and a decreased number of human leukocyte antigen (HLA) mismatches. To clarify the effects of donor relatedness and HLA mismatch on the outcomes after LDLT, we retrospectively analyzed 444 Japanese patients. Donors were blood relatives for 332 patients, spouses for 105, and "other" for 7. The number of HLA A-B-DR mismatches was none to two in 141, three in 123, and four to six in 106 patients. The 15-year survival rate was 52.6%, and PBC recurred in 65 patients. Recipient aged 61 years or older, HLA mismatches of four or more (maximum of six), graft:recipient weight ratio less than 0.8, and husband donor were adverse indicators of patient survival. IgM 554 mg/dL or greater, donor-recipient sex mismatch, and initial immunosuppression with cyclosporine were significant risks for PBC recurrence, which did not affect patient survival. In subgroup analysis, conversion to cyclosporine from tacrolimus within 1 year diminished recurrence. Prospective studies are needed to determine the influence of pregnancy-associated sensitization and to establish an optimal immunosuppressive regimen in LDLT patients.

Presence of antibodies against self human leukocyte antigen class II molecules in autoimmune hepatitis

Autoimmune hepatitis (AIH) can arise de novo after liver transplantation (LT) for non-autoimmune liver diseases. Considering the identical features of de novo AIH after LT and classical AIH, as well as the importance of anti-human leukocyte antigen (HLA) antibodies in graft rejection, we investigated the presence of circulating anti-HLA class II antibodies in the sera of 35 patients with AIH, 30 patients with primary biliary cirrhosis (PBC), and 30 healthy donors using fluorescent dye-impregnated beads bound to HLA molecules. We then investigated the allele specificity of the antibodies and identified the HLA alleles in each patient using DNA-based HLA typing. We also examined HLA class II expression in liver samples using immunohistochemistry. Anti-HLA class II antibodies were detected significantly more frequently in the patients with AIH (88.1%) than in the patients with PBC (33.3%) or in the healthy donors (13.3%) (both P <0.01). We confirmed that the anti-HLA class II antibodies in the AIH patients showed specificity for several HLA class II alleles, including self HLA class II alleles. Moreover, positive reactivity with anti-self HLA class II antibodies was associated with higher serum transaminase levels. In conclusion, we demonstrated, for the first time, that antibodies against self HLA class II alleles were detectable in patients with AIH. Our results suggest that an antibody-mediated immune response against HLA class II molecules on hepatocytes may be involved in the pathogenesis or acceleration of liver injury in AIH.