Influence of HLA-DQ Matching on Allograft Outcomes in Deceased Donor Kidney Transplantation

Antibody-mediated rejection owing to donor-specific HLA-DQA1 antibodies after renal transplantation: A case report

BACKGROUND

Donor-specific HLA antibodies are important risk factors in antibody-mediated rejection and graft loss after renal transplantation and are associated with higher rejection rates and lower graft survival. Most de novo donor specific antibodies (dnDSA) after renal transplantation are directed toward donor HLA-DQ antigens. An HLA-DQ antigen is a heterodimer consisting of an alpha and beta chain. Traditionally, HLA-DQA1 typing has not been part of pretransplant evaluation. Therefore, DQ alpha proteins are not usually considered in the interpretation of HLA-DQ antibody reactions.

METHODS

The renal transplant recipient had a 0% panel reactive antibody pretransplant. Two years after transplantation, he developed symptoms of abdominal distension and bilateral lower extremity edema. Histopathological findings on renal puncture biopsy showed a combination of T-cell-mediated acute rejection type IIA and antibody-mediated rejection with a trend toward chronicity in the transplanted kidney. DSAs were investigated by HLA-I (HLA-A/B) and HLA-II (HLA-DRB1/DQA1/DQB1) single antigen bead (SAB) assay. HLA typing was performed to explain the antibody reactivity patterns by PCR-SSO and Sequencing-based typing (SBT). HLAMatchmaker analysis was performed to identify eplets that explain antibody reactivity patterns.

RESULTS

HLA-II SAB analysis of the patient's serum at the time of rejection showed positive reactions with all DQB1*03:03-carrying beads with high mean fluorescence intensity (MFI). However, DQB1*03:03 was not a dnDSA antigen. High-resolution HLA typing revealed that HLA-DQA1*05:01 and DQA1*03:02 were mismatched donor antigens. HLA Matchmaker analysis demonstrated reactivity toward 130R and 116 V eplet on DQA1 and DQB1.

CONCLUSIONS

Antibodies specific to DQα chains after renal transplantation were highlighted.

The MHC class I MICA gene is a histocompatibility antigen in kidney transplantation

The identity of histocompatibility loci, besides human leukocyte antigen (HLA), remains elusive. The major histocompatibility complex (MHC) class I MICA gene is a candidate histocompatibility locus. Here, we investigate its role in a French multicenter cohort of 1,356 kidney transplants. MICA mismatches were associated with decreased graft survival (hazard ratio (HR), 2.12; 95% confidence interval (CI): 1.45–3.11; P < 0.001). Both before and after transplantation anti-MICA donor-specific antibodies (DSA) were strongly associated with increased antibody-mediated rejection (ABMR) (HR, 3.79; 95% CI: 1.94–7.39; P < 0.001; HR, 9.92; 95% CI: 7.43–13.20; P < 0.001, respectively). This effect was synergetic with that of anti-HLA DSA before and after transplantation (HR, 25.68; 95% CI: 3.31–199.41; P = 0.002; HR, 82.67; 95% CI: 33.67–202.97; P < 0.001, respectively). De novo-developed anti-MICA DSA were the most harmful because they were also associated with reduced graft survival (HR, 1.29; 95% CI: 1.05–1.58; P = 0.014). Finally, the damaging effect of anti-MICA DSA on graft survival was confirmed in an independent cohort of 168 patients with ABMR (HR, 1.71; 95% CI: 1.02–2.86; P = 0.041). In conclusion, assessment of MICA matching and immunization for the identification of patients at high risk for transplant rejection and loss is warranted.

Analysis of a multicenter cohort of kidney transplants shows that mismatches in the MICA locus and the presence of anti-MICA donor-specific antibodies are associated with reduced graft survival and increased rejection.

Clinical Outcome of Kidney Transplant Patients on the Allograft Function, Loss, Effects of HLA-DQB1-DSA+, and Graft Survival

INTRODUCTION

Matching for HLA-DQB1 molecules and anti-DQ donor-specific antibodies (DSAs) has been less studied to allocate transplants from deceased donors in developed countries. The aim of this study was to evaluate the clinical outcome of 519 kidney transplant recipients on the allograft function, loss, and survival and with emphasis on effects of HLA-DQB1-DSA⁺ at minimum of 10 years' follow-up.

METHODS

Five hundred nineteen kidney transplant patients were allocated into 3 groups (G) by immunologic profiles, namely, G1 (SPI-SAB HLA-DQ negative [DQ^-]), G2 (SPI-SAB HLA-DQ positive DSA negative [DQ⁺/DSA^-]), and G3 (SPI-SAB HLA-DQ DSA positive [DQ⁺ DSA⁺]), and the outcomes were reported until 10 years after transplantation.

RESULTS

The proportion of rejection episodes was higher in G3 (25.0% and 26.32%, respectively) than in G1 (8.63% and 6.82%, respectively) and G2 (10.0% and 0%, respectively; P = .047 and P = .014, respectively). In G3, 3 patients lost their grafts by antibody-mediated rejection. Patients who received kidneys from deceased donors (G3) showed worse graft survival rates than those from G1 donors (P = .001). Patients from G3 had a 2.18-fold higher risk of graft loss than patients from G1 (P = .028).

CONCLUSION

Allograft function was worse in G3 than in G2 or G1, and graft losses were more frequent by T-cell-mediated rejection in G1, and graft losses by antibody-mediated rejection were similar in G1 and G3 due to HLA class I (A1, 11 and B 8, 52) and HLA class II by DR7 and DQ 2, 5, 9 DSA, respectively. Allograft survival decreased in patients with HLA-DQB1 DSA. The risk of graft loss was 1.75-fold that in patients who received transplants from living donors.

Impact of the immunotherapy induction on allograft outcome and survival in kidney transplant patients with donor-specific antibodies to HLA-DQB1

BACKGROUND

The presence of donor-specific antibodies (DSAs) against HLA-DQB1 is considered a significant barrier to good outcome and allograft survival in kidney transplantation (KT). This study aimed to assess the impact of induction immunotherapy on the outcome and allograft survival in KT patients with HLA-DQB1-DSA.

METHODOLOGY

Thirty-two patients who had undergone KT and found to be positive for HLA-DQB1-DSA were monitored at least one to 10 years. They were allocated into two groups of patients: G1 received induction immunotherapy (n = 14 patients; 43.75%), and G2 did not (n = 18 patients; 56.25%).

RESULTS

In G1, 6 (42.86%) patients experienced rejection episodes (RE), 2 (14.29%) due to antibody-mediated rejection (ABMR) and 4 (28.57%) due to T-cell-mediated rejection (TCMR). In G2, 13 (72.22%) patients experienced RE, 3 (16.67%) due to ABMR, and 10 (55.56%) due to TCMR. Graft loss occurred in 4 patients from G1, 2 (14.29%) due to ABMR and 2 (14.29%) due to non-immunological causes. In G2, 9 (50.00%) patients lost their grafts, 2 (11.11%) due to TCMR, 2 (11.11%) due to ABMR, and 5 (27.78%) due to non-immunological causes. The graft survival rate was 64.29% in G1 and 45.83% in G2. Glomerulitis and peritubular capillaritis were observed in 3 and C4d-positive patients with/or without induction who lost their grafts by ABMR by HLA-DQ DSA. Two patients from G2 lost their graft by TCMR due to interstitial lymphocytic infiltrate (i1), foci of mild tubulitis (t2), interstitial edema, moderate interstitial fibrosis and tubular atrophy. Better graft survival rates were shown in patients from G1 who received induction immunotherapy.

CONCLUSION

Our study suggests that patients with an immunological profile of HLA-DQ+ DSA+ treated by immunotherapy induction have a decreased risk of ABMR and increased allograft survival, and the presence of anti-HLA-DQB1 DSA+ detected before and after KT were associated with ABMR episodes and failure.