- Email: [email protected]
OR33 Comparison of UCLA patients transplanted from the deceased donor waitlist during the new and previous UNOS kidney allocation systems
Abstracts / Human Immunology 76 (2015) 1–37
OR33
COMPARISON OF UCLA PATIENTS TRANSPLANTED FROM THE DECEASED DONOR WAITLIST DURING THE NEW AND PREVIOUS UNOS KIDNEY ALLOCATION SYSTEMS. Michelle J. Hickey 1, Ying Zheng 1, Ariel Moradzadeh 2, Nima Nassiri 2, Xiaohai Zhang 1, James Lan 1, Nicole Valenzuela 1, Eileen W. Tsai 2, Jennifer Q. Zhang 1, Jeffrey Veale 2, David Gjertson 1, Michael Cecka 1, Elaine F. Reed 1. 1 UCLA Immunogenetics Center, Los Angeles, CA, United States; 2 UCLA David Geffen School of Medicine, Los Angeles, CA, United States. Aim: UNOS implemented a new kidney allocation system (New KAS) on December 4, 2014 with the goal of increasing patient and allograft post-transplant survival. We aimed to determine the effects of the New KAS on UCLA patients transplanted from the deceased donor waitlist in comparison to the previous allocation system (Previous KAS). Methods: We evaluated isolated kidney transplants from the deceased donor waitlist during the first three months of the new KAS (12/4/2014–3/4/2015) and compared to the same time period during the Previous KAS (12/4/2013–3/4/2014). Demographic and clinical information were collected by reviewing the patient’s UNOS removal data and medical record. Information describing deceased donors were gathered from UNOS DonorNet. Results: The total number of deceased donor isolated kidney transplants was increased in the New KAS as compared to the Previous KAS (42 vs 26). Transplant of regraft patients and of highly sensitized patients with cPRA P98% was also significantly increased (New KAS vs Previous KAS, 42.9% vs 11.5%, p 6 0.007, and 31.0% vs 0.0%, p 6 0.001, respectively). In the New KAS, the percentage of patient’s receiving allografts imported from outside our local area was increased (33.3 vs 19.2). Imported organs were allocated either to very highly sensitized P 99% cPRA) patients receiving a second transplant (71.4%) or had very high KDPI and were allocated to patients with 0% cPRA (21.4%). Recipients and donors with age differences exceeding 15 years was decreased in the New KAS as compared to the Previous KAS (50.0 vs 29.0%, p 6 0.12). There was a 76% reduction in transplant to patients in the 65 + age group in the New KAS (p 6 0.016). We have not observed a paucity in transplant of pediatric patients (0–17 years, New KAS vs Previous KAS, 9.5% vs 3.8%, respectively). The percentage of patients transplanted with preformed donor specific antibody (DSA) is increased in the New KAS in comparison to the Previous KAS (33.3 vs 15.4%, respectively). Outcome measures will be evaluated after 3 months follow up. Conclusion: The data show that the New KAS is working as designed to better age match recipients and donors and to increase transplantation of very highly sensitized patients through broader sharing.
OR34
FLOW AND VIRTUAL CROSS MATCH EXCHANGE – A NEW COMPONENT OF THE INTERNATIONAL CELL EXCHANGE. Arlene F. Locke, James H. Lan, Qiuheng Zhang, David Gjertson, Elaine F. Reed. UCLA Immunogenetics Center, Los Angeles, CA, United States. Aim: Single antigen bead assays provide investigators with a means to accurately identify the presence and relative strength of HLA antibodies through the use of MFI (Mean Fluorescence Intensity) values. However, inter-laboratory variation to the interpretation of MFI values creates the potential for discordant results. The aim of this study was to provide a medium to compare and correlate MFI data together with flow crossmatch outcomes. Methods: In 2014, the International Cell Exchange program introduced the UCLA Flow and Virtual Cross Match Exchange. In three exchanges, a total of 6 cells and 12 sera were tested by 17 laboratories around the world. T and B flow cytometric crossmatch results, along with class I and class II single antigen data were reported and analyzed. Fifteen laboratories used a Luminex single antigen bead assay (LSAB) and 2 used a flow single antigen bead assay (FSAB). To further investigate the correlation between MFI values and positive flow crossmatch results, the strength of donor-specific antibodies were compared with their crossmatch outcomes. In addition, coefficients of variations (%CV) were calculated using the MFI reported for each DSA and by each laboratory. We also examined the prediction of positive T/B virtual crossmatches in relationship to the strength of DSAs identified. Results: The mean class I and class II DSA MFI of the positive T and B flow crossmatches were 15355 and 14641, respectively. Among labs reporting LSAB MFI, the mean %CV was 26%. Overall, 16 (67%) T-cell and 8 (33%) B-cell flow crossmatch challenges were reported among the labs without discordance. When restricting analysis to DSA MFI greater than mean values, the T flow concordance rate improved to 79%, while B flow concordance remained poor at 31%. In contrast, high concordance rates were observed for virtual crossmatch predictions: 92% (22/24) for T- and 88% (21/24) for B-cell crossmatches. Conclusions: The data suggests that the variability of cell based assays is higher than that observed in solid phase SAB test. It also suggests that variability exists in the sensitivity of flow crossmatch testing among laboratories and that this variability is correlated with DSA strength. As such, educational activities should continue to provide standards for quality control of antibody and crossmatch testing methods.
29
OR33
COMPARISON OF UCLA PATIENTS TRANSPLANTED FROM THE DECEASED DONOR WAITLIST DURING THE NEW AND PREVIOUS UNOS KIDNEY ALLOCATION SYSTEMS. Michelle J. Hickey 1, Ying Zheng 1, Ariel Moradzadeh 2, Nima Nassiri 2, Xiaohai Zhang 1, James Lan 1, Nicole Valenzuela 1, Eileen W. Tsai 2, Jennifer Q. Zhang 1, Jeffrey Veale 2, David Gjertson 1, Michael Cecka 1, Elaine F. Reed 1. 1 UCLA Immunogenetics Center, Los Angeles, CA, United States; 2 UCLA David Geffen School of Medicine, Los Angeles, CA, United States. Aim: UNOS implemented a new kidney allocation system (New KAS) on December 4, 2014 with the goal of increasing patient and allograft post-transplant survival. We aimed to determine the effects of the New KAS on UCLA patients transplanted from the deceased donor waitlist in comparison to the previous allocation system (Previous KAS). Methods: We evaluated isolated kidney transplants from the deceased donor waitlist during the first three months of the new KAS (12/4/2014–3/4/2015) and compared to the same time period during the Previous KAS (12/4/2013–3/4/2014). Demographic and clinical information were collected by reviewing the patient’s UNOS removal data and medical record. Information describing deceased donors were gathered from UNOS DonorNet. Results: The total number of deceased donor isolated kidney transplants was increased in the New KAS as compared to the Previous KAS (42 vs 26). Transplant of regraft patients and of highly sensitized patients with cPRA P98% was also significantly increased (New KAS vs Previous KAS, 42.9% vs 11.5%, p 6 0.007, and 31.0% vs 0.0%, p 6 0.001, respectively). In the New KAS, the percentage of patient’s receiving allografts imported from outside our local area was increased (33.3 vs 19.2). Imported organs were allocated either to very highly sensitized P 99% cPRA) patients receiving a second transplant (71.4%) or had very high KDPI and were allocated to patients with 0% cPRA (21.4%). Recipients and donors with age differences exceeding 15 years was decreased in the New KAS as compared to the Previous KAS (50.0 vs 29.0%, p 6 0.12). There was a 76% reduction in transplant to patients in the 65 + age group in the New KAS (p 6 0.016). We have not observed a paucity in transplant of pediatric patients (0–17 years, New KAS vs Previous KAS, 9.5% vs 3.8%, respectively). The percentage of patients transplanted with preformed donor specific antibody (DSA) is increased in the New KAS in comparison to the Previous KAS (33.3 vs 15.4%, respectively). Outcome measures will be evaluated after 3 months follow up. Conclusion: The data show that the New KAS is working as designed to better age match recipients and donors and to increase transplantation of very highly sensitized patients through broader sharing.
OR34
FLOW AND VIRTUAL CROSS MATCH EXCHANGE – A NEW COMPONENT OF THE INTERNATIONAL CELL EXCHANGE. Arlene F. Locke, James H. Lan, Qiuheng Zhang, David Gjertson, Elaine F. Reed. UCLA Immunogenetics Center, Los Angeles, CA, United States. Aim: Single antigen bead assays provide investigators with a means to accurately identify the presence and relative strength of HLA antibodies through the use of MFI (Mean Fluorescence Intensity) values. However, inter-laboratory variation to the interpretation of MFI values creates the potential for discordant results. The aim of this study was to provide a medium to compare and correlate MFI data together with flow crossmatch outcomes. Methods: In 2014, the International Cell Exchange program introduced the UCLA Flow and Virtual Cross Match Exchange. In three exchanges, a total of 6 cells and 12 sera were tested by 17 laboratories around the world. T and B flow cytometric crossmatch results, along with class I and class II single antigen data were reported and analyzed. Fifteen laboratories used a Luminex single antigen bead assay (LSAB) and 2 used a flow single antigen bead assay (FSAB). To further investigate the correlation between MFI values and positive flow crossmatch results, the strength of donor-specific antibodies were compared with their crossmatch outcomes. In addition, coefficients of variations (%CV) were calculated using the MFI reported for each DSA and by each laboratory. We also examined the prediction of positive T/B virtual crossmatches in relationship to the strength of DSAs identified. Results: The mean class I and class II DSA MFI of the positive T and B flow crossmatches were 15355 and 14641, respectively. Among labs reporting LSAB MFI, the mean %CV was 26%. Overall, 16 (67%) T-cell and 8 (33%) B-cell flow crossmatch challenges were reported among the labs without discordance. When restricting analysis to DSA MFI greater than mean values, the T flow concordance rate improved to 79%, while B flow concordance remained poor at 31%. In contrast, high concordance rates were observed for virtual crossmatch predictions: 92% (22/24) for T- and 88% (21/24) for B-cell crossmatches. Conclusions: The data suggests that the variability of cell based assays is higher than that observed in solid phase SAB test. It also suggests that variability exists in the sensitivity of flow crossmatch testing among laboratories and that this variability is correlated with DSA strength. As such, educational activities should continue to provide standards for quality control of antibody and crossmatch testing methods.
29