April 16, 2021
A 2020 Banff Antibody Mediated Injury Working Group examination of international practices for diagnosing antibody mediated rejection in kidney transplantation
By: Dave Lowe
- Biopsy data is accompanied by DSA data in +/- 30% of cases, suggesting urgent action to improve the accessibility of DSA information is needed.
- Publication agrees with the recent Leuven paper that Banff ABMR nomenclature is insufficient and does not capture the full spectrum of ABMR.
- One third of pathologists agree that Banff 17 does not adequately deal with histologic changes that are “suspicious for ABMR” in the absence of DSA or C4d positivity.
Banff ABMR Workgroup calls out deficiencies in Banff 17 recommendations.
In this article, the Banff Antibody-mediated injury workgroup surveyed an international cohort of nephrologists, surgeons, and renal pathologists to determine how antibody-mediated rejection (ABMR) is diagnosed in clinical practice. Crucially, and despite being a central testing requirement for the diagnosis of ABMR, the survey revealed that in most cases (>60%) reported by the respondents, DSA information was not available at the time of diagnosis. Several reasons were proposed to explain the absence or delay in DSA results. These included:
- Unavailability of HLA information needed to confirm the presence of DSA
- Laboratory imposed workflow constraints
- DSA testing not always routinely ordered
- Limited communication with HLA laboratory
Furthermore, the survey revealed that around of third of respondents felt that Banff ’17 did not adequately account for the histologic changes considered “suspicious for ABMR” when observed in the absence of DSA or positive C4d staining. Additionally, many of those also surveyed report taking into account other factors not included in the Banff classification, such as the testing timepoint post-transplant when making their diagnosis.
Another key finding is that even when DSA is absent, and the biopsy shows features indicative of ABMR, roughly 20% of those surveyed routinely order additional non-HLA testing or molecular transcript analysis, with >80% of respondents citing a belief that these tests will not change patient management.
The authors put forward a compelling argument that the tools needed for optimal use of the Banff ABMR classification system are not being utilized or are not always readily available, although they observe that using these tools is vital in achieving an accurate ABMR diagnosis. Without this, it becomes difficult to study factors such as treatment efficacy or the underlying disease mechanisms.
The survey also calls for greater efforts from researchers, histocompatibility experts, and pathologists to increase the understanding of the roles of HLA and non-HLA antibodies in kidney transplantation. The study concludes that, at the very least, the focus should be placed on expanding the accessibility of DSA test results. From improving the level of available donor HLA typing (specifically the inclusion of DQ and DP typing) to developing processes to ensure serum availability for future DSA testing, the authors highlight many areas of improvement that would positively impact the accuracy of ABMR diagnosis in the future.