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Abstracts / Human Immunology 73 (2012) 49–167
CENTERS WITH A VERY LOW PERCENTAGE OF BROADLY SENSITIZED CANDIDATES CAN HAVE A NEGATIVE IMPACT ON THE EFFICIENCY OF KIDNEY ALLOCATION. Anna Y. Kucheryavaya 1, Nancy L. Reinsmoen 2, Lee Ann Baxter-Lowe 3, J. Michael Cecka 4. 1 Research, United Network for Organ Sharing, Richmond, VA, USA; 2 Cedars Sinai Comprehensive Transplant Center, HLA Laboratory, Los Angeles, CA, USA; 3 Laboratory, UCSF Immunogenetics & Transplant Laboratory, San Francisco, CA, USA; 4 Immunogenetics Center, UCLA, Los Angeles, CA, USA. Aim: 16% of adult kidney alone registrations in the US are broadly sensitized (80%+ CPRA). But some programs have a much lower percentage of such registrations. The aim of this study was to compare positive crossmatch rates and allocation in programs grouped according to their percentage of broadly sensitized patients. Methods: Data for adult kidney alone registrations were compared for three groups of large transplant programs (100+ candidates). Group 1 included programs with <5% of broadly sensitized candidates, group 2 programs with 5-<10% and group 3 programs with 10-20%. Results are based on the Organ Procurement and Transplantation Network (OPTN) database. Results: On 12/31/11, groups 1 and 2 had similar percentages of retransplant and female registrations (12% vs. 12%, 35% vs. 37%) and group 3 had higher percentages (15% for retransplant and 41% for females). In 2011, transplant rates were not significantly different between three groups. Group 1 had a significantly higher percentage of offers refused due to a positive crossmatch compared to groups 2 and 3 (1.5% vs. 0.3% and 0.4% for all offers, and 21% vs. 5% and 8% for offers to 80%+ CPRA patients). Group 1 also had a significantly higher percentage of offers accepted for transplant but kidneys not transplanted into the intended recipient (43% of all accepted offers vs. 21% and 5% for all offers, and 81% vs. 31% and 9% for offers accepted for 80%+ CPRA patients). In 2011, group 1 refused 191 offers due to a positive crossmatch and in 137 cases, an offer was accepted but the kidney was not ultimately transplanted into the intended recipient. Conclusions: The data seem to suggest that centers with a very low percentage of broadly sensitized candidates (group 1) may not be listing a realistic number of unacceptable antigens for their patients. High rates of refusals due to a positive crossmatch and offers accepted but kidneys not transplanted into the intended recipient can have a negative impact on the efficiency of kidney allocation.
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DETECTION OF ANTI-HLA ANTIBODY: COMPARATIVE EVALUATION OF LABSCREEN AND LIFECODES ANTIBODY LUMINEX ASSAYS. Abdelhamid Liacini 1,2,3, Luz Stamm 1, Noureddine Berka 1,2. 1 Pathology & Laboratory Medicine, Tissue Typing Laboratory, Calgary Laboratory Services, Calgary, AB, Canada; 2 Pathology & Laboratory Medicine, University of Calgary, Dammam, AB, Canada; 3 Pathology & Laboratory Medicine, Histocompatibility & Immunogenetics Laboratory King (HIL) Fahad Specialist Hospital, Dammam, Saudi Arabia. Aim: Clinical relevance of anti-HLA antibodies in Solid Organ Transplantation field is of outmost importance. Solid-phase assays using purified HLA antigens are predominantly used in HLA laboratories. We undertook this study to validate LABScreen (LSM 12, One Lambda) Luminex assay in comparison to our current screening method (Lifecodes). Sera were collected from active renal patients from our kidney waitlist during the quarterly screening period. Methods: A total of 150 sera was tested of which 146 gave results for either HLA class I and/or II antibodies by LABScreen Mixed kits (One Lambda Inc., USA) and LIFECODES LifeScreen Deluxe kits (GenProbe, USA). The screen results were confirmed by One Lambda single antigen beads (SAB). Lifecodes single antigen beads were not validated used in this study. Results: There was a 73% (106/146) concordance between the two methods. The discrepancies were equally distributed among class I and II screens. Most class I false negative screens were due to Cw and shared epitopes as confirmed by single antigen testing. Class II false negative results were due to DP antibodies. As predicted, LABScreen does correlate better with SAB results used currently by our laboratory. The two screen assays use slightly different protocol both require good techniques to yield consistent results. They are both affected by tech to tech and run to run variability and one assay is slightly cheaper than the other. Conclusions: There was a 73% concordance between the two methods, with one method coming short in some HLA antigens. It is important to interrogate patient sera frequently (at least 2 single antigens pre-transplant) with more than one method. Laboratories who are planning to introduce these assays must conduct extensive parallel testing confirmed by single antigens and/or flow PRA.
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Abstracts / Human Immunology 73 (2012) 49–167
CENTERS WITH A VERY LOW PERCENTAGE OF BROADLY SENSITIZED CANDIDATES CAN HAVE A NEGATIVE IMPACT ON THE EFFICIENCY OF KIDNEY ALLOCATION. Anna Y. Kucheryavaya 1, Nancy L. Reinsmoen 2, Lee Ann Baxter-Lowe 3, J. Michael Cecka 4. 1 Research, United Network for Organ Sharing, Richmond, VA, USA; 2 Cedars Sinai Comprehensive Transplant Center, HLA Laboratory, Los Angeles, CA, USA; 3 Laboratory, UCSF Immunogenetics & Transplant Laboratory, San Francisco, CA, USA; 4 Immunogenetics Center, UCLA, Los Angeles, CA, USA. Aim: 16% of adult kidney alone registrations in the US are broadly sensitized (80%+ CPRA). But some programs have a much lower percentage of such registrations. The aim of this study was to compare positive crossmatch rates and allocation in programs grouped according to their percentage of broadly sensitized patients. Methods: Data for adult kidney alone registrations were compared for three groups of large transplant programs (100+ candidates). Group 1 included programs with <5% of broadly sensitized candidates, group 2 programs with 5-<10% and group 3 programs with 10-20%. Results are based on the Organ Procurement and Transplantation Network (OPTN) database. Results: On 12/31/11, groups 1 and 2 had similar percentages of retransplant and female registrations (12% vs. 12%, 35% vs. 37%) and group 3 had higher percentages (15% for retransplant and 41% for females). In 2011, transplant rates were not significantly different between three groups. Group 1 had a significantly higher percentage of offers refused due to a positive crossmatch compared to groups 2 and 3 (1.5% vs. 0.3% and 0.4% for all offers, and 21% vs. 5% and 8% for offers to 80%+ CPRA patients). Group 1 also had a significantly higher percentage of offers accepted for transplant but kidneys not transplanted into the intended recipient (43% of all accepted offers vs. 21% and 5% for all offers, and 81% vs. 31% and 9% for offers accepted for 80%+ CPRA patients). In 2011, group 1 refused 191 offers due to a positive crossmatch and in 137 cases, an offer was accepted but the kidney was not ultimately transplanted into the intended recipient. Conclusions: The data seem to suggest that centers with a very low percentage of broadly sensitized candidates (group 1) may not be listing a realistic number of unacceptable antigens for their patients. High rates of refusals due to a positive crossmatch and offers accepted but kidneys not transplanted into the intended recipient can have a negative impact on the efficiency of kidney allocation.
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DETECTION OF ANTI-HLA ANTIBODY: COMPARATIVE EVALUATION OF LABSCREEN AND LIFECODES ANTIBODY LUMINEX ASSAYS. Abdelhamid Liacini 1,2,3, Luz Stamm 1, Noureddine Berka 1,2. 1 Pathology & Laboratory Medicine, Tissue Typing Laboratory, Calgary Laboratory Services, Calgary, AB, Canada; 2 Pathology & Laboratory Medicine, University of Calgary, Dammam, AB, Canada; 3 Pathology & Laboratory Medicine, Histocompatibility & Immunogenetics Laboratory King (HIL) Fahad Specialist Hospital, Dammam, Saudi Arabia. Aim: Clinical relevance of anti-HLA antibodies in Solid Organ Transplantation field is of outmost importance. Solid-phase assays using purified HLA antigens are predominantly used in HLA laboratories. We undertook this study to validate LABScreen (LSM 12, One Lambda) Luminex assay in comparison to our current screening method (Lifecodes). Sera were collected from active renal patients from our kidney waitlist during the quarterly screening period. Methods: A total of 150 sera was tested of which 146 gave results for either HLA class I and/or II antibodies by LABScreen Mixed kits (One Lambda Inc., USA) and LIFECODES LifeScreen Deluxe kits (GenProbe, USA). The screen results were confirmed by One Lambda single antigen beads (SAB). Lifecodes single antigen beads were not validated used in this study. Results: There was a 73% (106/146) concordance between the two methods. The discrepancies were equally distributed among class I and II screens. Most class I false negative screens were due to Cw and shared epitopes as confirmed by single antigen testing. Class II false negative results were due to DP antibodies. As predicted, LABScreen does correlate better with SAB results used currently by our laboratory. The two screen assays use slightly different protocol both require good techniques to yield consistent results. They are both affected by tech to tech and run to run variability and one assay is slightly cheaper than the other. Conclusions: There was a 73% concordance between the two methods, with one method coming short in some HLA antigens. It is important to interrogate patient sera frequently (at least 2 single antigens pre-transplant) with more than one method. Laboratories who are planning to introduce these assays must conduct extensive parallel testing confirmed by single antigens and/or flow PRA.