TABLE 6.
Subgroup analysis- Comparison between cases with and without AAMR in the HLAi group.
| No AAMR (n = 47) | AAMR (n = 11) | p-value | ||
|---|---|---|---|---|
| Donor age, years | 40 (31–46) | 43 (27–51) | 0.87 | |
| Donor gender, n (%) (missing cases n = 2) | Female | 18 (42) | 5 (45) | 1.0 |
| Male | 26 (58) | 6 (55) | ||
| Donor ethnicity, n (%) (missing cases n = 3) | White | 37 (84) | 10 (90) | 1.0 |
| Ethnic minorities | 7 (16) | 1 (10) | ||
| Recipient age, years | 43 (35–54) | 42 (35–56) | 0.70 | |
| Recipient gender, n (%) | Female | 28 (60) | 8 (73) | 0.50 |
| Male | 19 (40) | 3 (27) | ||
| Recipient ethnicity, n (%) | White | 39 (83) | 10 (91) | 1.0 |
| Ethnic minorities | 8 (17) | 1 (11) | ||
| Recipient dialysis status, n (%) | Pre-emptive | 3 (6) | 0 | 1.0 |
| HD or PD | 44 (94) | 11 (100) | ||
| Duration on dialysis, months | 60 (31–133) | 66 (16–96) | 0.71 | |
| Previous transplant, n (%) | No | 21 (45) | 6 (55) | 0.74 |
| Yes | 26 (55) | 5 (45) | ||
| High risk relation*, yes, n (%) | 12 (25) | 5 (45) | 0.27 | |
| Peak cRF | 97 (89–99) | 99 (95–100) | 0.11 | |
| HLA mismatch level, n (%) | Level 0, 1 and 2 | 6 (13) | 1 (9) | 1.0 |
| Level 3 and 4 | 41 (87) | 10 (91) | ||
| DSA to repeat mismatches, n (%) (missing cases n = 4) | No | 19 (43) | 2 (20) | 0.23 |
| Yes | 25 (57) | 8 (80) | ||
| C1q complement fixing DSA, n (%) (missing cases n = 20) | No | 18 (53) | 0 | 0.11 |
| Yes | 16 (47) | 4 (100) | ||
| C3d complement fixing DSA, n (%) (missing cases n = 20) | No | 21 (62) | 0 | 0.03 |
| Yes | 13 (38) | 4 (100) | ||
| Class I DSA MFI, baseline | 9,422 (5,516–13814) | 17,872 (14,514–26958) | 0.01 | |
| Class II DSA MFI, baseline | 3,138 (0–9,565) | 11,760 (773–26489) | 0.12 | |
| Total DSA MFI, baseline | 14,583 (9,037–21691) | 32,519 (23,371–45928) | 0.001 | |
| Class I DSA MFI, pre-transplant (missing cases n = 13) | 3,663 (1,498–7,749) | 11,686 (2,334–17249) | 0.056 | |
| Class II DSA MFI, pre-transplant (missing cases n = 13) | 1,299 (0–5,153) | 5,770 (0–8,768) | 0.33 | |
| Total DSA MFI, pre-transplant (missing cases n = 5) | 7,080 (3,752–11359) | 12,883 (4,034–23991) | 0.10 | |
| FCXM, B or T cell, baseline, n (%) (missing cases n = 1) | Negative µ | 2 (4) | 0 | 0.43 |
| Weak positive | 7 (15) | 0 | ||
| Strong positive | 37 (81) | 11 (100) | ||
| FCXM, B or T cell, pre-transplant, n (%) (missing cases n = 5) | Negative | 27 (64) | 6 (54) | 0.14 |
| Weak positive | 7 (17) | 0 | ||
| Strong positive | 8 (19) | 5 (46) | ||
| Baseline T-cell FCXM, RMF | 2.5 (1.73–3.42) | 3.42 (2.2–9.64) | 0.07 | |
| Baseline B-cell FCXM, RMF | 3.86 (2.82–6.3) | 6.44 (5.34–10.10) | 0.02 | |
| Pre-transplant T-cell FCXM, RMF (only 1 case in each group) | N/A | N/A | ||
| Pre-transplant B-cell FCXM, RMF (among positive cases) | 2.86 (2.49–3.3) | 3.93 (3.65–4.08) | 0.02 | |
Values expressed as Median (IQR), unless otherwise stated. µ These two cases were grouped in HLAi, as their pre-transplant FCXM, was weakly positive, *High risk relation between donor and recipient includes child to mother, or husband to wife relationship. Abbreviations: HLAi, Human Leukocyte antigen incompatible kidney transplantation; AAMR, aggressive antibody mediated rejection; cRF, calculated reaction frequency; DSA, donor specific antibody; MFI, median fluorescence index; FCXM, flow cytometry crossmatch; RMF, relative mean fluorescence ratio.