A Low Immuknow Level but Behold….pAMR1(H+) Rejection
Tampa General Hospital, Tampa, FL
Meeting: 2022 American Transplant Congress
Abstract number: 1133
Keywords: Antibodies, Endomyocardial biopsy, Immunosuppression, T cell activation
Topic: Clinical Science » Heart » 63 - Heart and VADs: All Topics
Session Information
Session Time: 7:00pm-8:00pm
Presentation Time: 7:00pm-8:00pm
Location: Hynes Halls C & D
*Purpose: PURPOSE: The purpose of this study is to evaluate the mechanism of pAMR1(H+) rejection in heart transplant recipients with low ImmuKnow levels (ATP <225 ng/ml).
*Methods: METHODS: A single center study of heart transplant recipients who had a histologic EMB diagnosing pAMR1(H+) rejection and concomitant ImmuKnow, Allosure and MMDX from 1/2019 to 6/2021 were entered into the study. The recipients with pAMR1(H+) rejection were divided into two groups, one with a low ImmuKnow level (ATP <225 ng/ml) and one with a normal ImmuKnow level (ATP 226-524 ng/ml). The MMDX gene endoscripts and Allosure result were compared between the two groups using the Students t-test.
*Results: RESULTS: There were 32 heart transplant recipients included in the study. The low ImmuKnow group had 16 recipients with 26 episodes of pAMR1(H+) rejection and the normal ImmuKnow group had 16 recipients with 27 episodes of pAMR1(H+) rejection. The ImmuKnow level in the low group was 115 ±63 ng/ml and the normal group was 359 ±74 ng/ml.In the low ImmuKnow group 8/16 recipients had DSA’s -seven Class II, one Class I and II, and the normal ImmuKnow group 9/16 recipients had DSA’s -all Class II.The NKB endoscript was elevated nine fold over baseline in both ImmuKnow groups. The normal ImmuKnow group TCMR endoscripts were 1.5 times more elevated than the low ImmuKnow group (p<0.001). The DSAST endoscript in the low ImmuKnow group was 1.4 times more elevated than in the normal ImmuKnow group (p< 0.025).The Allosure result was elevated in both the low ImmuKnow group 1.78 ±1.49 and normal ImmuKnow group 1.35 ±1.34 (p NS).
| NORMAL | LOW CMI | NORMAL CMI | p VALUE | ||
| AMR | DSAST | <0.08 | 0.64±0.22 | 0.47±0.32 | p<0.025 |
| eDSAST | <0.16 | 0.36±0.22 | 0.31±0.25 | p NS | |
| NKB | <0.12 | 0.94±0.45 | 0.93±0.38 | p NS | |
| ROBO4 | <9.49 | 10.02±0.38 | 9.94±0.36 | P NS | |
| TCMR | QCAT | <0.15 | 0.84±0.40 | 1.32±0.55 | p<0.001 |
| TCB | <0.30 | 0.81±0.58 | 1.19±0.69 | p<0.05 | |
| REJECTION | GRIT | <0.11 | 0.83±0.28 | 0.91±0.34 | p<0.5 |
*Conclusions: With a low ImmuKnow level the odds of developing an infection are increased and rejection decreased. However, a low ImmuKnow level does not preclude Humoral rejection. pAMR1(H+) or non-complement mediated rejection can be caused by NK cells of the innate immune system which are CD4 receptor negative. The ImmuKnow assesses the degree of immunosuppression of the acquired immune system not the innate immune system.
To cite this abstract in AMA style:
Weston MW. A Low Immuknow Level but Behold….pAMR1(H+) Rejection [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/a-low-immuknow-level-but-behold-pamr1h-rejection/. Accessed May 18, 2025.« Back to 2022 American Transplant Congress