Is HLA class II DNA typing needed for cadaver donor processing?
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80 Abstracts C-6.1 #147 IS HLA CLASS II DNA TYPING NEEDED FOR CADAVER DONOR PROCESSING? MA Moir-Lennon, GA Teresi, TC Li, DJ Mancuso and DJ Cook. The Cleveland Clinic Foundation Transplant Center, Cleveland, OH. DNA class II typing assays offer the possibility of greater sensitivity and specificity than do serologic class II typing assays. Correct class II matching with cadaver donors is essential since the UNOS kidney allocation system is influenced by DR antigen matching. Abbreviated DNA assays (2- 4 hours) are now available and could be employed when processing cadaver donors. In order to assess the advantages of DNA typing for this situation, we compared serologic class II results using our local tray identifying DR1-16 in our last 54 cadaver donors with SSOP DNA class II typing results involving 103 alleles. DR antigen phenotypes agreed for 47 of the donors (87%). In six cases serologically defined antigens were disparate when compared to the DNA result. As shown, the dis )arities were limited to DR1, 3, 13, 14 and 16. DONOR SEROLOGY DR DNA DR UNOS EFFECT? GM 15 N CD 13,14 1501,1601 1301/06,1302 N AL 13,15 0103,1501 Y TK 3,6 1301,* Y* ML 3,13 1301,1302" Y* MM 3,6 301,1301 N In three of these cases, the disparity noted would not have effected the UNOS sharing algorithm as the split antigens would have been converted to the parent. The one case involving DRB1 "103 would have impacted the matching algorithm, as the DR13 antigen identified by serology was not present. However, because of the difficulty in identifying the DRB1 * 103 antigen, it is unlikely that calling this a DR1 would have resulted in a match for this particular allele. In the remaining 2 cases, we believe that the serological result may be accurate, and that these cases may involve a DRB1 "3012 allele or other variant which our SSOP would not have identified (sequencing is in progress). In conclusion, we feel that implementation of DNA typing would have had a minimal effect on the allocation of kidneys from these donors. SSOP typing, resulting in a more accurate assessment of HLA class II matching, could be performed retrospectively, as this information would not necessarily be of use pretransplant. C-6.1 #148 DNA HETERODUPLEX ANALYSIS OF HLA-DRB ALLELES IN SEROLOGIC- ALLY MATCHED CADAVERIC KIDNEY TRANSPLANTS. JK Connolly 2, AJ Ivinsont, PJ Sinnott t, S Martin t, NR Parrott a, RWG Johnson2 and PA Dyer 1. INW Regional Yissue Typing Laboratory, St Mary's Hospital, Manchester and 2Renal Transplant Unit, Manchester Royal Infirmary. Current UK kidney transplantation matching criteria are based on the serological definition of HLA polymorphisms. DNA based HLA Class II typing has demonstra- ted many more allelic variants than are detectable using routine serological techni- ques. Using a DNA heteroduplex technique, we have performed retrospective analysis of HLA-DRB alleles using PCR amplification of DNA from donor/recipient cadaveric kidney transplant pairs which were allocated prospectively on the basis of two HLA- DR antigen matches using serological techniques. From 400 transplants performed between May 1989 and May 1992 there were 187 first transplants with two HLA-DR matches and to date 67 pairs have been analysed. In 32 (48%) donor/recipient pairs heteroduplex analysis detected differences in al- leles. The alleles which most frequently showed discordance by heteroduplex analysis belonged to the HLA-DR6 and DR7 specificities; there are 16 recognised alleles of DR6 but only 2 of DR7. Allelic discordance was lowest for HLA-DR3 (3 known alleles) and was detected in only 8 out of 22 donor/recipient pairs. This effect maybe explained by allelic association within the common haplotype HLA-A1, -B8, -DR3. There was no statistically significant difference between heteroduplex concordance and discordance with graft survival, or number and severity of rejection episodes. We conclude that a larger study using a more heterogeneous population is needed to clarify the nature of these mismatches and their relevance to transplant outcome.
Transcript of Is HLA class II DNA typing needed for cadaver donor processing?
80 Abstracts
C-6.1 #147
IS HLA CLASS II DNA TYPING NEEDED FOR CADAVER DONOR PROCESSING? M A Moi r -Lennon, GA Teresi, TC Li, DJ Mancuso and DJ Cook. The Cleveland Clinic Foundat ion Transp lant Center, Cleveland, OH.
DNA class II typing assays offer the possibility of greater sensitivity and specificity than do serologic class II typing assays. Correct class II matching wi th cadaver donors is essential since the UNOS kidney allocation system is influenced by DR antigen matching. Abbreviated DNA assays (2- 4 hours) are now available and could be employed when processing cadaver donors. In order to assess the advantages of DNA typing for this situation, we compared serologic class II results using our local tray identifying DR1-16 in our last 54 cadaver donors wi th SSOP DNA class II typing results involving 103 alleles. DR antigen phenotypes agreed for 47 of the donors (87%). In six cases serologically defined antigens were disparate when compared to the DNA result. As shown, the dis )arities were limited to DR1, 3, 13, 14 and 16.
DONOR SEROLOGY DR DNA DR UNOS EFFECT? GM 15 N CD 13,14
1501,1601 1301/06,1302 N
AL 13,15 0103,1501 Y TK 3,6 1301,* Y* ML 3,13 1301 ,1302" Y* MM 3,6 301,1301 N
In three of these cases, the disparity noted would not have effected the UNOS sharing algorithm as the split antigens would have been converted to the parent. The one case involving DRB1 "103 would have impacted the matching algorithm, as the DR13 antigen identified by serology was not present. However, because of the difficulty in identifying the DRB1 * 103 antigen, it is unlikely that calling this a DR1 would have resulted in a match for this particular allele. In the remaining 2 cases, we believe that the serological result may be accurate, and that these cases may involve a DRB1 "3012 allele or other variant which our SSOP would not have identified (sequencing is in progress). In conclusion, we feel that implementation of DNA typing would have had a minimal effect on the allocation of kidneys from these donors. SSOP typing, resulting in a more accurate assessment of HLA class II matching, could be performed retrospectively, as this information would not necessarily be of use pretransplant.
C-6.1 #148
DNA HETERODUPLEX ANALYSIS OF HLA-DRB ALLELES IN SEROLOGIC- ALLY MATCHED CADAVERIC KIDNEY TRANSPLANTS. JK Connolly 2, AJ Ivinson t, PJ Sinnott t, S Martin t, NR Parrott a, RWG Johnson 2 and PA Dyer 1. INW Regional Yissue Typing Laboratory, St Mary's Hospital, Manchester and 2Renal Transplant Unit, Manchester Royal Infirmary.
Current UK kidney transplantation matching criteria are based on the serological definition of HLA polymorphisms. DNA based HLA Class II typing has demonstra- ted many more allelic variants than are detectable using routine serological techni- ques.
Using a DNA heteroduplex technique, we have performed retrospective analysis of HLA-DRB alleles using PCR amplification of DNA from donor/recipient cadaveric kidney transplant pairs which were allocated prospectively on the basis of two HLA- DR antigen matches using serological techniques.
From 400 transplants performed between May 1989 and May 1992 there were 187 first transplants with two HLA-DR matches and to date 67 pairs have been analysed. In 32 (48%) donor/recipient pairs heteroduplex analysis detected differences in al- leles. The alleles which most frequently showed discordance by heteroduplex analysis belonged to the HLA-DR6 and DR7 specificities; there are 16 recognised alleles of DR6 but only 2 of DR7. Allelic discordance was lowest for HLA-DR3 (3 known alleles) and was detected in only 8 out of 22 donor/recipient pairs. This effect maybe explained by allelic association within the common haplotype HLA-A1, -B8, -DR3. There was no statistically significant difference between heteroduplex concordance and discordance with graft survival, or number and severity of rejection episodes.
We conclude that a larger study using a more heterogeneous population is needed to clarify the nature of these mismatches and their relevance to transplant outcome.
