Ann Lab Med 2023; 43(4): 325-327

Published online July 1, 2023

Copyright © Korean Society for Laboratory Medicine.

Impact of Low-level Donor-specific Antibody Determined With a Positive Luminex and Negative Flow Cytometric Crossmatch on Kidney Transplantation Outcomes

Minjeong Nam, M.D., Ph.D.1 and Eun Young Song, M.D., Ph.D.2

1Laboratory Medicine, Korea University College of Medicine, Seoul, Korea; 2Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Korea

Correspondence to: Eun Young Song, M.D., Ph.D.
Department of Laboratory Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea
Tel: +82-2-2072-2540, Fax: +82-2-747-0359, E-mail:

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Since the introduction of the Luminex technique to detect donor-specific antibodies (DSAs) in kidney transplantation, efforts have been made to determine the risk of pre-operative low-level DSAs. The risk of low-level DSAs can be stratified by the mean fluorescence intensity (MFI), based on the highest level or sum [1]. However, the relative amount of antigen expressed on Luminex beads for each HLA locus varies from that expressed in vivo [2]. Therefore, caution is needed when applying the same MFI criteria to each HLA locus. Accordingly, the flow cytometric crossmatch test, which detects the actual binding of a DSA to donor lymphocytes, remains an important pre-transplantation test despite recognized limitations such as inter-laboratory and person-to-person variations or false positives due to non-HLA antibodies [3]. Therefore, it is meaningful to analyze the clinical impact of pre-operative low-level DSAs determined by a positive Luminex result but negative flow cytometric crossmatch (PLNF) on kidney transplantation outcomes.

Previous studies demonstrating these effects reported diverse results [4, 5]. In 2012, a meta-analysis including seven studies concluded that the risk of antibody-mediated rejection (AMR) and graft failure increased in patients with PLNF results compared to that in patients without DSAs, even when using the Luminex assay [4]. However, a subsequent meta-analysis published in 2019 also analyzing seven studies showed no significant increase in the risk of acute rejection, 1-year graft survival, or 5-year graft survival [5].

The major contributor to these discrepant results is the use of different criteria for selecting patients among studies. First, the type of kidney donor could be different (living vs. deceased-donor). Clinical outcomes of deceased-donor transplantation are known to be worse than those of living-donor transplantation [6, 7]. Second, the inclusion or exclusion of patients with pre-operative desensitization treatment can affect the study results [8-10]. Third, the collection of serum before or after desensitization prior to transplantation will have a large impact. DSA levels were found to be lower for samples collected after desensitization, which would result in more favorable clinical outcomes as the risk of DSAs is minimized [8, 11]. Conversely, studies using sera after desensitization or excluding patients who underwent desensitization indicated an increase in the risk of AMR, although the risk of graft failure did not increase [9, 11].

In this issue of Annals of Laboratory Medicine, Lee, et al. [12] reported the results of an analysis of 1,090 kidney transplantation patients (629 living and 398 deceased donors), wherein 178 patients (127 living and 51 deceased donors) had undergone desensitization before transplantation. In these 178 patients, sera collected after desensitization prior to transplantation were used for DSA analysis using the Luminex assay and flow cytometric crossmatch approach. The authors found the risk of AMR to be increased in patients with PLNF compared to that in patients without DSAs, whereas the risk of graft failure did not, when using the Luminex assay. In particular, the impact of AMR was more pronounced in patients who underwent deceased-donor transplantation than in those who underwent living-donor transplantation. This result was concordant with those of previous studies reporting worse outcomes in deceased-donor transplantation [5, 6]. In this study by Lee, et al. [12], a higher proportion of low-level DSA (PLNF) patients with living donors received desensitization treatment, including not only rituximab but also plasmapheresis/intravenous immunoglobulin, which might have contributed to a better allograft outcome. Desensitization treatment did not increase the risk of post-transplant infection in their study. Given its well-known association with better allograft outcomes despite the presence of DSAs, several institutions consider desensitization treatment. Lee, et al. [12] showed that patients who received desensitization treatment to achieve low-level DSA (PLNF) before transplantation did not have a notable increase in the risk of graft failure, and there was also no increased risk of post-transplant infection.

Despite the main limitation of the study by Lee, et al. [12] as a single-institution study, this work has the advantage of accurately determining the effect of low-level DSA (PLNF) on kidney transplantation outcomes using a unified immunosuppressive treatment protocol. The authors did not analyze the peak MFI before desensitization, which might have affected the study results. Further evaluation of low-level DSA based on PLNF and the MFI strength of DSAs using sera collected both before and after desensitization would be warranted, as it is known that the peak MFI strength of DSAs before desensitization can affect transplantation outcomes [13, 14].

In summary, pre-operative PLNF might (or might not) increase the risk of AMR, depending on several factors such as the type of donor or desensitization protocol employed. Nevertheless, PLNF seems to have minimal impact on graft survival. Further studies including multiple centers with unified desensitization, immunosuppressive regimens, and treatment for rejection protocols are needed for validation of these results.

Nam M drafted the manuscript; Song EY designed, reviewed, and revised the manuscript. Both authors read and approved the final manuscript.

  1. Ziemann M, Altermann W, Angert K, Arns W, Bachmann A, Bakchoul T, et al. Preformed donor-specific HLA antibodies in living and deceased donor transplantation: a multicenter study. Clin J Am Soc Nephrol 2019;14:1056-66.
    Pubmed KoreaMed CrossRef
  2. Tait BD, Süsal C, Gebel HM, Nickerson PW, Zachary AA, Claas FH, et al. Consensus guidelines on the testing and clinical management issues associated with HLA and non-HLA antibodies in transplantation. Transplantation 2013;95:19-47.
    Pubmed CrossRef
  3. Kang H, Yoo J, Lee SY, Oh EJ. Causes of positive pretransplant crossmatches in the absence of donor-specific anti-human leukocyte antigen antibodies: a single-center experience. Ann Lab Med 2021;41:429-35.
    Pubmed KoreaMed CrossRef
  4. Mohan S, Palanisamy A, Tsapepas D, Tanriover B, Crew RJ, Dube G, et al. Donor-specific antibodies adversely affect kidney allograft outcomes. J Am Soc Nephrol 2012;23:2061-71.
    Pubmed KoreaMed CrossRef
  5. Buttigieg J, Ali H, Sharma A, Halawa A. Positive Luminex and negative flow cytometry in kidney transplantation: a systematic review and meta-analysis. Nephrol Dial Transplant 2019;34:1950-60.
    Pubmed CrossRef
  6. Hart A, Lentine KL, Smith JM, Miller JM, Skeans MA, Prentice M, et al. OPTN/SRTR 2019 annual data report: kidney. Am J Transplant 2021;21 Suppl 2:21-137.
    Pubmed CrossRef
  7. Laging M, Gestel JAK, Haasnoot GW, Claas FHJ, van de Wetering J, Ijzermans JNM, et al. Transplantation results of completely HLA-mismatched living and completely HLA-matched deceased-donor kidneys are comparable. Transplantation 2014;97:330-6.
    Pubmed CrossRef
  8. Orandi BJ, Garonzik-Wang JM, Massie AB, Zachary AA, Montgomery JR, Van Arendonk KJ, et al. Quantifying the risk of incompatible kidney transplantation: a multicenter study. Am J Transplant 2014;14:1573-80.
    Pubmed CrossRef
  9. Adebiyi OO, Gralla J, Klem P, Freed B, Davis S, Wiseman AC, et al. Clinical significance of pretransplant donor-specific antibodies in the setting of negative cell-based flow cytometry crossmatching in kidney transplant recipients. Am J Transplant 2016;16:3458-67.
    Pubmed CrossRef
  10. Kwon H, Kim YH, Choi JY, Shin S, Jung JH, Park SK, et al. Impact of pretransplant donor-specific antibodies on kidney allograft recipients with negative flow cytometry cross-matches. Clin Transplant 2018;32:e13266.
    Pubmed CrossRef
  11. Higgins R, Lowe D, Hathaway M, Williams C, Lam FT, Kashi H, et al. Human leukocyte antigen antibody-incompatible renal transplantation: excellent medium-term outcomes with negative cytotoxic crossmatch. Transplantation 2011;92:900-6.
    Pubmed CrossRef
  12. Lee H, Lee H, Eum SH, Ko EJ, Min JW, Oh EJ, et al. Impact of low-level donor-specific anti-HLA antibody on posttransplant clinical outcomes in kidney transplant recipients. Ann Lab Med 2023;43:325-7.
    Pubmed CrossRef
  13. Chung BH, Choi BS, Oh EJ, Park CW, Kim JI, Moon IS, et al. Clinical impact of the baseline donor-specific anti-human leukocyte antigen antibody measured by Luminex single antigen assay in living donor kidney transplant recipients after desensitization therapy. Transpl Int 2014;27:49-59.
    Pubmed CrossRef
  14. Lefaucheur C, Loupy A, Hill GS, Andrade J, Nochy D, Antoine C, et al. Preexisting donor-specific HLA antibodies predict outcome in kidney transplantation. J Am Soc Nephrol 2010;21:1398-406.
    Pubmed KoreaMed CrossRef