Repeat HLA-B and -DR loci mismatching at second liver transplantation improves patient survival

HLA matching between donors and recipients improves clinical liver transplant graft survival

BACKGROUND AND AIMS

The importance of human leukocyte antigen (HLA) matching between liver transplant donors and recipients on graft survival remains unclear and is not a clinical consideration in liver transplantation. This study aimed to determine the relationship between HLA matching and liver graft survival using a large-scale multi-centre database (UNOS/OPTN) and multivariate logistic analysis. The secondary aim was to determine whether this relationship was influenced by transplant indication and donor status.

METHODS

This retrospective observational analysis was performed using 22 702 liver transplant recipients from the UNOS/OPTN database. Patients were divided into two groups based on number of HLA mismatches (0-3 mismatches vs. 4-6 mismatches) and then subcategorized by indication and donor status. Risk-adjusted outcomes were assessed by multivariate Cox analysis adjusting for donor and recipient characteristics and visualized using Kaplan-Meier survival curves.

RESULTS

Allograft survival and risk of acute rejection were associated with degree of HLA mismatch. This association between HLA mismatch and graft survival persisted in individuals who underwent transplant for hepatitis, metabolic, drug toxicity, and congenital indications. Donor status also influenced the relationship between HLA mismatch and graft survival. Graft survival in DBD recipients was longer than in DCD in the 4-6 HLA mismatch group, whereas no significant difference was found in the 0-3 HLA mismatch group.

CONCLUSION

HLA mismatch significantly reduced graft survival and increased risk of acute rejection. This association was noted only in specific indications. These findings are of potential clinical relevance to organ allocation, allograft matching algorithms, immunosuppression protocols, and transplant surveillance.

The impact of human leukocyte antigen donor and recipient serotyping and matching on liver transplant graft failure in primary sclerosing cholangitis, autoimmune hepatitis, and primary biliary cholangitis

Human leukocyte antigen (HLA) serotyping is not considered to have significant impact on liver graft survival and does not factor into U.S. organ allocation. Immune-related liver diseases such as primary sclerosing cholangitis (PSC), autoimmune hepatitis (AIH), and primary biliary cholangitis (PBC) have been speculated to represent a disease subgroup that may have significantly different graft outcomes depending on HLA donor/recipient characterization. The aim of this study was to investigate whether HLA serotyping/matching influenced post-transplant graft failure for immune-related liver diseases using the United Network for Organ Sharing database. From 1994 to 2015, 5665 patients underwent first-time liver-only transplants for PSC, AIH, and PBC with complete graft survival and donor/recipient HLA data. Graft failure was noted in 38.6% (2188/5665), and all groups had comparable 5-year graft survival (75.1%-78.8%, P = 0.069). The overall degree of, and loci-specific mismatch level, did not influence outcomes. Multivariable Cox proportional hazards regression noted increased graft failure risk for recipient HLA-B7, HLA-B57, HLA-B75, HLA-DR13 and donor HLA-B55, HLA-B58, and HLA-DR8 for PSC patients, protective effects for recipient HLA-DR1 and HLA-DR3 for AIH patients, and increased risk for HLA-DR7 for AIH patients. These findings warrant further investigation to evaluate the impact of HLA serotyping on post-transplant outcomes.

Long-term outcome of human leukocyte antigen mismatching in liver transplantation: results of the National Institute of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database

A perfect or nearly perfect human leukocyte antigen (HLA) match has been associated with better immediate and long-term survival of diseased donor kidney transplants. However, the effect of HLA matching for hepatic allografts remains poorly defined. Using data from the National Institutes of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database, we investigated the association between HLA mismatches and hepatic allograft survival, disease recurrence, and immunosuppression interactions. A, B, and DR loci were used to calculate total mismatch scores of 0 (no mismatches in any loci) to 6 (mismatches in all loci). Seven hundred ninety-nine adults (male, 55%; female, 45%) underwent 883 liver transplants. The 10-year graft survival according to total mismatch score was as follows: 0-2, 60%; 3-4, 54%; and 5-6, 57%. There was a negative effect of mismatching at the A locus on patient survival, with shorter survival for patients with 1 or 2 mismatches compared with 0 mismatches [P = 0.05, hazard ratio (HR) = 1.6]. Patients on tacrolimus with 1 or 2 mismatches at B or DR loci appeared to have increased rates of patient and graft survival compared to patients with 0 mismatches, with the appearance of a protective effect of tacrolimus (HR = 0.67). The effect of HLA mismatching was more pronounced on certain disease recurrences. DR-locus mismatch increased recurrence of autoimmune hepatitis (P = 0.01, HR = 4.2) and primary biliary cirrhosis (P = 0.04, HR = 2). Mismatch in the A locus was associated with more recurrence of hepatitis C virus (P = 0.01, HR = 1.6) and primary sclerosing cholangitis (P = 0.03, HR = 2.9).

CONCLUSION

Mismatching at the A locus decreases patient survival in liver transplant recipients, and mismatching at the DR and A loci affects recurrence of autoimmune liver diseases and hepatitis C, respectively.

Preformed antibodies detected by cytotoxic assay or multibead array decrease liver allograft survival: role of human leukocyte antigen compatibility

The significance of human leukocyte antigen (HLA) compatibility and preformed antibodies in liver transplantation remains unclear. The objectives of this study were to evaluate, in a single-center cohort comprising 896 liver transplants, whether the degree of donor-recipient compatibility and preformed antibodies modified graft survival. Univariate Kaplan-Meier analysis demonstrated that donor-recipient HLA compatibility had a marginal impact on allograft survival. As for compatibility at individual antigen loci, 2 mismatches at HLA-A conferred a survival advantage in retransplanted allografts (P = 0.011). HLA-B and HLA-DR loci did not play a significant role in outcome in any pathology. The concordance of results on preformed antibodies detected by complement-dependent cytotoxicity (CDC) and a multiple bead assay (Luminex xMAP) showed a strong correlation between both techniques (P < 0.0001). Both CDC-detected and Luminex-detected antibodies were associated with shorter graft survival within the first year post-transplant (P = 0.01 and P = 0.016, respectively). Positive CDC T crossmatches and Luminex-detected HLA class II antibodies played a significant role in decreasing graft survival (P = 0.043 and P = 0.0019 at 1 year, respectively, and P = 0.005 and P = 0.038 at 5 years, respectively). A correlation was also observed between the presence of preformed Luminex-detected class II or Luminex I and II antibodies and allograft rejection (P = 0.001 and P = 0.042, respectively). In conclusion, although HLA typing is not a prerequisite for transplantation, screening of HLA antibodies with Luminex techniques and CDC crossmatch may be useful in the detection of at-risk patients that could benefit from increased surveillance and tailored therapy following transplantation.

A large, single center investigation of the immunogenetic factors affecting liver transplantation

BACKGROUND

Reports on the relevance of immunogenetic factors in liver transplantation are often conflicting or inconclusive. We have, therefore, investigated a range of factors that may underlie liver graft survival.

METHODS

The influences of HLA, flow cytometric, and enhanced cytotoxic crossmatching and immunoglobulin (Ig)A levels on graft survival, and acute and chronic rejection were investigated for a single center involving 446 patients over 13 years.

RESULTS

The effect of HLA mismatching on graft survival was significant (P<10(-2)) and was reversed in recipients with autoimmune diseases (P<0.5x10(-2)), whereas the effect of HLA mismatches on the level of acute rejection was detrimental in all recipients. There was a significant effect of a positive cytotoxic crossmatch on 3-month (P<10(-5)) and 1-year (P<10(-4)) graft survival, and an additional effect of the flow cytometric crossmatch was seen for chronic rejection (P<10(-2)) and acute rejection (P<10(-2)). Recipients with HLA-A1,B8,DRB1*0301 had higher levels of acute rejection (P<0.5x10(-2)), and recipients who received an ABO compatible-nonidentical transplant have a significantly higher risk (P<10(-2)) of developing chronic rejection. Finally, the beneficial effect of high serum IgA and, specifically, IgA anti Fab, seen in renal transplants was not evident in liver transplants, and in fact the opposite may be true, at least for acute rejection (P<0.5x10(-2)).

CONCLUSIONS

By separating the recipients with autoimmune disease from other patients and by including acute and chronic rejection as outcome parameters, we have used the power of a large single-centre study to delineate the significance of some of the important immunogenetic factors involved in liver transplantation.

Increased late hepatic artery thrombosis rate and decreased graft survival after liver transplants with zero cross-reactive group mismatches

The use of broad-specificity cross-reactive groups (CREGs) at the A and B HLA loci has been proposed as a means to improve both access and outcome for renal transplantation but has not yet been studied for liver transplantation. We retrospectively analyzed our results for all adult liver transplantations performed at our center between 1989 and 1996 for which HLA typing and complete 3-year follow-up data were available. Two hundred eight transplantations were studied, with a mean follow-up of 66 +/- 2 months (range, 36 to 110 months); A and B loci were converted to CREGs by the method of Rodey. Thirteen percent of the patients with 0 CREG mismatches had hepatic artery thrombosis versus 2% for those with 1 or more mismatches (odds ratio, 6.7; 95% confidence interval, 2.6 to 17.3 by univariate analysis; odds ratio, 3.5; 95% confidence interval, 1.1 to 11.7 by logistic regression analysis). These events occurred significantly later in the 0-CREG mismatch group (21 +/- 7 v 4 +/- 2 months posttransplantation; P =.04 by Student's t-test). Graft survival rates were significantly lower for patients with 0 CREG mismatches (56% v 68% at end of study; P =.05 by Cox-Mantel test). The number of CREG mismatches had no effect on the frequency of rejection, steroid-resistant rejection, or infectious complications, including cytomegalovirus. Neither total nor individual A, B, or DR HLA matching had an effect on outcome. There appears to be little evidence that intentional CREG matching would improve outcomes for liver transplantation and, under some circumstances, could be deleterious.

Effect of partial HLA class I match on acute rejection in viral pre-infected human liver allograft recipients

BACKGROUND

Acute rejection in liver transplants is one of the commonest causes of liver dysfunction in the early postoperative period. However, the factors involved in liver graft rejection are still unknown. Our study was aimed at ascertaining whether the degree of HLA class I and class II compatibility or pretransplant viral infection have any influence on early acute liver graft rejection.

METHODS

We reviewed clinical and laboratory data in 190 consecutive patients who underwent a liver transplant. HLA-A, HLA-B, and HLA-DR typing for the establishment of an HLA match score was performed by a standard microcytotoxicity method. The existence of pretransplant viral infection was investigated in sera and biopsy tissue by serologic (hepatitis B virus, hepatitis C virus) and polymerase chain reaction (cytomegalovirus) techniques, respectively. The influence of these two factors in acute rejection and the interaction between them was also analyzed.

RESULTS

A strong association between viral infection and acute rejection in the group with partial class I matching was found (odds ratio=7.75; P<0.0009), whereas no correlation was observed in the group with zero class I matching (odds ratio=0.98; P=0.81). The rejection percentage in the group in which partial class I match and viral infections coexisted was 60%, whereas in the partially class I-matched group without pretransplant viral presence it was 16%.

CONCLUSIONS

These findings suggest a participation of partial HLA class I compatibility in triggering acute rejection in recipients suffering preoperative viral infections and support the idea that HLA class I antigen matching could play a role as a linking element between the MHC-restricted T cell-mediated response to viral infection and the allogenic response in liver transplantation.