BACKGROUND: The diagnosis of antibody mediated rejection (AMR) is standardized based on the ISHLT pAMR grading scale which stratifies biopsies based on the presence or absence of histological and immunological changes. By this scale, pAMR1 is defined as the presence of histological or immunological changes on biopsy, and is termed "suspicious" for AMR, while pAMR2 requires both histological and immunological changes and is termed "positive" for AMR. Severe changes merit a
diagnosis of pAMR3. The purpose of this study was to assess the incidence of circulating antibodies in patients with pAMR1versus pAMR2 and pAMR3.
METHODS: We evaluated 191 biopsies graded according to the new ISHLT AMR grading scale. Biopsies were pAMR 0 (n=127), pAMR 1 (n=53), pAMR 2 (n=8), pAMR 3 (n=3). The presence of circulating antibodies was assessed within 2 weeks of the biopsy sample. Subsequent 1 year survival following the pAMR on biopsy was assessed.
RESULTS: Nonspecific antibodies and donor specific antibodies (DSA) were more commonly associated with pAMR2 and pAMR3 on biopsy. Left ventricular function and subsequent 1 year survival did not differ among groups.
|pAMR Endpoints||pAMR 0 (N=127)||pAMR 1 (N=53)||pAMR 2 (N=8)||pAMR 3 (N=3)|
|Mean Time to pAMR, Days± SD||–||24±54||72±126||216±197*|
|Positive PRA within 2 weeks of pAMR, n(%)||25/92 (27.2%)||19/51(37.3%)||8/8 (100%)*,**||3/3 (1005)*,**|
|DSA within 2 weeks of pAMR (%)||11/92 (12.0%)||10/51 (19.6%)||6/8 (75.0%)*,**||3/3 (100%)*,**|
|Subsequent 1 year Survival, n(%)||122/127 (96.1%)||51/53 (96.2%)||7/8 (87.5%)||3/3 (100%)|
|Mean Subsequent 1 year LVEF, %LVEF±SD||58%±7% (n=80)||59%±7% (n=31)||59%±2% (n=3)||60% (n=2)|
CONCLUSION: Circulating antibodies, including DSA, are more common with pAMR2 and pAMR3 versus pAMR1 and pAMR0. These findings suggest that pAMR2/3 is a distinct entity from pAMR1 and supports the distinction between pAMR 2/3 and pAMR1 in the new ISHLT pAMR grading scale.
Reinsmoen, N.: Speaker’s Bureau, One Lambda.
To cite this abstract in AMA style:Patel J, Kittleson M, Rafiei M, Osborne A, Chang D, Czer L, Reinsmoen N, Kobashigawa J. Presence of Circulating Antibodies at the Time of Pathology Defined Antibody-Mediated Rejection after Heart Transplant: Are They out There?, The [abstract]. Am J Transplant. 2013; 13 (suppl 5). https://atcmeetingabstracts.com/abstract/presence-of-circulating-antibodies-at-the-time-of-pathology-defined-antibody-mediated-rejection-after-heart-transplant-are-they-out-there-the/. Accessed October 27, 2020.
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