**7. HLA-matching in kidney allocation from deceased donors**

Most renal transplant programs preferentially allocate kidneys from deceased donors to transplant candidates with favourable HLA compatibility. The current allocation of deceaseddonor kidneys in most countries, including Australia and the Eurotransplant group (Germany, The Netherlands, Belgium, Luxembourg, Slovenia, and Austria), is weighted largely on the degree of mismatched antigens at the HLA-A, -B and -DR loci, with less emphasis on other factors such as time on dialysis, prior sensitization and even ischaemic time. When a potential deceased-donor kidney is available in Australia, transplant candidates on the wait-list are ranked according to an allocation score calculated from a combination of factors including the number of HLA-mismatches, age of recipient, degree of sensitization and time on wait-list [91]. Approximately 20% of deceased donor kidneys are allocated on a national level to highly sensitized transplant candidates (around 20% of kidneys allocated) but the remaining 80% of deceased donor kidneys are allocated through individual state allocation algorithms.

**Study Cohort Rejection Graft survival**

Vascular: 19% T-B- vs 32% T-B+ (p=0.01); DSA was a significant predictor for vascular or glomerular rejection

The presence of SAB HLA-DSA on the peak and current serum has a PPV for AMR of 35% and 32% respectively. Prevalence of AMR 1% in patients with MFI <465, 19% MFI between 466 and 3000, 36% MFI between 3001 and 6000, and 51% MFI "/>6000. Peak HLA-DSA Luminex MFI predicted AMR better than current HLA-DSA MFI.

The incidence of AMR among patients with preformed DSA was 35%, 9-fold higher than in patients without DSA (3%) (p <

Overall incidence of clinical/ subclinical rejection (i.e., AMR and acute T-cell mediated rejection) at day 200 posttransplant was significantly higher in patients with HLADSA (48/67; 71%) than in patients without HLA-DSA (94/267; 35%).

HLA – human leukocyte antigen, DD – deceased donor, LD – live-donor, CDC-XM – complement dependent cytotoxicity cross-match, DSA – donor-specific antibodies, SAB – single antigen bead, AMR – antibody mediated rejection, DCGS –

Most renal transplant programs preferentially allocate kidneys from deceased donors to transplant candidates with favourable HLA compatibility. The current allocation of deceased-

death-censored graft survival, MFI – mean fluorescent intensity, PPV – positive predictive value.

**7. HLA-matching in kidney allocation from deceased donors**

**Table 1.** Association between donor-specific antibodies and graft outcomes.

0.001).

Graft loss: T-B+ - 44%; T-B- 27%

5 and 8-year DCGS were 89% and 84% in non-sensitized patients, 92% and 92% in sensitized patients with no peak HLA-DSA, and 71% and 61% in patients with peak HLA-DSA. Relative risk (RR) for graft loss for patients who had an episode of AMR was 4.1 (95% CI 2.2 to 7.7) as compared with patients without

Overall graft survival at 8 years was 68% in patients with DSA and 77% in those with no DSA. Graft survival of patients with DSA and AMR was significantly worse than in DSA patients without AMR and in non-

DCGS at 5 years was 89% in those without DSA, 87% with DSA but no AMR and 68% with DSA and AMR.

(especially class I DSA)

AMR.

DSA patients.

83 T-B+ XM vs 386 T-B-XM; IgG HLA DSA in 33% of T-B+ XM patients

358 Current Issues and Future Direction in Kidney Transplantation

83 (21%) positive DSA by Luminex by peak sera vs 76 (19%) by current sera

All negative T and B-cell CDC-XM. 27% class I or II anti-HLA antibody with

332 negative T and B cell CDC-XM, 67 DSA vs 267 no DSA by Luminex

52% DSA.

*Eng H et al* (n=471 DD renal transplant recipients) [*79*]

*Lefaucheur C et al* (n=402 DD renal transplant recipients)

*Lefaucheur C et al* (n=237 LD and DD renal transplant recipients) [*81*]

*Amico P et al (n=334 LD and DD renal transplant recipients)*

*[105]*

[*80*]

Despite efforts to achieve equity of access to transplantation in many countries, the inclusion of HLA matching in the allocation of deceased donor kidneys is believed to disadvantage transplant candidates with uncommon HLA phenotypes [92]. Consequently, indigenous populations and ethnic minorities often have a much longer transplant wait-list time and are less likely to receive well-matched kidneys [97-100]. The elimination of the allocation priority for HLA-B mismatches has been shown to improve the transplant potential of ethnic minorities but this approach has not been widely adopted by other countries [61].

In Australia, unacceptable class I HLA-mismatches are defined using the Luminex platform and the presence of class I DSA against HLA-A and -B antigens with >2000 mean fluorescent intensity (MFI) excludes transplant candidates from receiving these donor kidneys, independ‐ ent of the CDC-cross match results. At present, class II DSA is not explicitly considered in the allocation of kidneys from deceased donors in Australia but many centres have already adopted the policy of avoiding transplantation of kidneys into transplant candidates with high levels of class II DSA.
