PMID- 36687549
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20231031
IS  - 0973-6247 (Print)
IS  - 1998-3565 (Electronic)
IS  - 0973-6247 (Linking)
VI  - 16
IP  - 2
DP  - 2022 Jul-Dec
TI  - Prozone phenomenon in pretransplant testing: An interesting conundrum involving 
      solid-phase and cell-based assays.
PG  - 180-185
LID - 10.4103/ajts.ajts_145_20 [doi]
AB  - BACKGROUND: Human leukocyte antigen (HLA) is a major determinant in deciding upon 
      solid organ histocompatibility. Donor-specific anti-HLA antibodies 
      (Donor-specific anti-HLA antibodies (DSAs)) are always a contraindication for 
      solid organ transplantation, and identification of DSA becomes very crucial 
      before transplantation to provide long-term graft survival. For identification of 
      DSA, usually, either cell-based or HLA bead-based assay is being used in 
      laboratories. However, both cell-based and bead-based assays have certain 
      limitations. One such common limitation is "prozone effect," which can give 
      false-negative results. Here, we would like to present a small pilot study to 
      analyze the effect of the prozone phenomenon in the cell-based and HLA bead-based 
      assays and its utility in histocompatibility testing. MATERIALS AND METHODS: In a 
      series of four experiments, cell-based assay, flow cytometric cross-match (FCXM), 
      and HLA bead-based flow cytometric panel reactive antibodies (PRAs) were 
      performed. Single-antigen bead (SAB) testing was conducted as a first experiment 
      on four known positives samples for anti-HLA antibody-antibodies. In the second 
      experiment, these four samples were pooled together (called pooled sera in the 
      text) and tested for FCXM and PRA. In the third experiment, known commercially 
      available positive control sera were mixed with pooled positive sera (positive 
      control sera + pooled sera) to prepare, what we have called "positive concoction" 
      in the text. In the fourth experiment, the positive concoction was diluted 
      serially (1:2, 1:4, 1:8, and 1:16) and FCXM and PRA were performed again to 
      analyze and compare the prozone effect. RESULTS: Pooled sera did not have the 
      expected median fluorescence intensity (MFI) values in FCXM assay, whereas the 
      PRA was showing >90% positivity. In positive concoction, the MFI of FCXM assay 
      was observed to be declining; however, PRA values remained almost constant. 
      Dilutions of the pooled sera showed that MFI values of FCXM assays were increased 
      suddenly after dilution. The highest MFI values were observed in 1:4 dilution of 
      the sera, and then, it declined gradually, but the PRA values remained almost 
      constant even after serial dilutions. CONCLUSION: In our experimental findings, 
      it was clear that cell-based assay (FCXM) was more severely affected by the 
      prozone, whereas solid-phase (flow PRA) assay remained resistant to prozone.
CI  - Copyright: (c) 2022 Asian Journal of Transfusion Science.
FAU - Singh, Parvind
AU  - Singh P
AD  - Department of Transplant Immunology, Chimera Transplant Research Foundation, New 
      Delhi, India.
FAU - Tiwari, Aseem Kumar
AU  - Tiwari AK
AD  - Department of Transfusion Medicine, Medanta - The Medicity, Gurugram, Haryana, 
      India.
FAU - Mishra, Vikash Chandra
AU  - Mishra VC
AD  - Department of Transplant Immunology, Chimera Transplant Research Foundation, New 
      Delhi, India.
FAU - Deshpande, Trupti Vimlakar
AU  - Deshpande TV
AD  - Department of Transplant Immunology, Chimera Transplant Research Foundation, New 
      Delhi, India.
FAU - Dorwal, Pranav
AU  - Dorwal P
AD  - Department of Flowcytometry, Waikato Hospital, Hamilton, New Zealand.
FAU - Bhardwaj, Amit Kr
AU  - Bhardwaj AK
AD  - Department of Transplant Immunology, Chimera Transplant Research Foundation, New 
      Delhi, India.
FAU - Kumari, Sneha
AU  - Kumari S
AD  - Department of Transplant Immunology, Chimera Transplant Research Foundation, New 
      Delhi, India.
FAU - Raina, Vimarsh
AU  - Raina V
AD  - Department of Transplant Immunology, Chimera Transplant Research Foundation, New 
      Delhi, India.
LA  - eng
PT  - Journal Article
DEP - 20220727
PL  - India
TA  - Asian J Transfus Sci
JT  - Asian journal of transfusion science
JID - 101306858
PMC - PMC9855212
OTO - NOTNLM
OT  - Anti-human leukocyte antigen antibodies
OT  - flow cytometric cross-match
OT  - flow cytometry
OT  - panel reactive antibodies
OT  - prozone effect (hook effect)
OT  - single-antigen bead assay
OT  - solid-phase immunoassay
COIS- There are no conflicts of interest.
EDAT- 2023/01/24 06:00
MHDA- 2023/01/24 06:01
PMCR- 2022/07/01
CRDT- 2023/01/23 05:05
PHST- 2020/09/22 00:00 [received]
PHST- 2021/05/16 00:00 [revised]
PHST- 2021/06/22 00:00 [accepted]
PHST- 2023/01/23 05:05 [entrez]
PHST- 2023/01/24 06:00 [pubmed]
PHST- 2023/01/24 06:01 [medline]
PHST- 2022/07/01 00:00 [pmc-release]
AID - AJTS-16-180 [pii]
AID - 10.4103/ajts.ajts_145_20 [doi]
PST - ppublish
SO  - Asian J Transfus Sci. 2022 Jul-Dec;16(2):180-185. doi: 10.4103/ajts.ajts_145_20. 
      Epub 2022 Jul 27.