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Predictability of DTT cross match
Abstracts
125
(122) P r e d i c t a b i l i t y o f D T T C r o s s M e t c h M.IL Mickey, M. Lau, B. Carnahan, and P.I. Ternsaki
UCLA Tissue Typing Laboratory, UCLA, Los Angeles, CA Kidneys shipped for pteseleceed patients are often transplanted into others because of positive crossmatch. We have been interested in computer p:edicdon of crossmatch to a~oki most of the mhdirection. The prediction is based on panel pretesting of recipient sera and the HLA type of the donor. We sought to eliminsre the prediction errors av.ributable to non-HLA cytotoxic antibodies by pretreatment of sera with DTi'. We res~ed the prediction in a laboratory study in which prediction equations for 116 sera from waiting patients were based nn a frozen panel of 140 cells and applied to predicting test outcome for t38 simulated donor cells. Ninety-six percent of all psedkdons of negative test outcome were correct for D T r and 91% were correct for the same sera without DTI'. Few negative predictions were made for sera with 90%-100% PRA end only about half were correct. For ? 0 % - 9 0 ~ PILA, 89% were correct with DTI" and 82% for controh. For sere |tom candidates for first TX, 93% of negative predictions were correct for 7 0 % - 9 0 % PRA compared to 83% for candidates fog re-transplant. We conclude that negative crossmatch outcome can now he predicted acceptably well for patients with PRA less than 90%, a practically imporumt achievement. More work is requited to eliminate s e n exchange for the very highly sensitized patients.
(123) D N A T e c h n i q u e s i n T i s s u e T y p i n g D. Middleton, D . Savage, C. O'Neill, and J. Martin
Northern lrdand Tissue Typing Service, BdfaJt, Irdand We have D N A RFLP typed 160 renal patients either transplanted or awaiting a transplant to compare the results obtained to those of convenfio~ml serolng/c typing. The restriction enzyme Te~qland probes for HI.A-DR/3, I-ILA-DQ~, and HLA-DQ~ genes were used. The serologic ,'ype differed from the RFIL.._?type in 27 (17%) of patients. In 5 ~ t i e n t s an incorrect antigen has been assigned by serology and in 22 patients an antigen detected by RFLP was not detected by serology. In add/don, RFLP techniques have enabled the splitting of DR5 and DR6, antigens for which it is difficult to obtain suitable sera, and to split DB3 and DRT, antigens that previously were thought not to have splits. R~suhs will be presented o f the frequency o f these splits. their association with HLA-B locus antigens and the relationship of variants Of DRw52 to these splits. The use of RFLP has also allowed the determination of D Q antigens and the delin~t/on of new splits at this locus. O n only two occasions, due to poor D N A yields, was a repest sample requ/red for RFLP typing. In contrast 44% of patients had to he serologicaBy ~ on at least t~0 occasions, indeed the a v e r s e number of typiegs for each patient was 1.9. Other advantages offered by RFLP are the ability to type samples up to 7 days old and to confirm homozygosity without reference to family members, 17% of patients were found to be homozygous.
(124) I s o l a t i o n a n d E x p r e s s i o n o f a c D N A C l o n e E n c o d i n g a n H L A - C w 6 G e n e S. M i z u n o , S. g a n g , H , Lee, J,A. Trap~fi, and S.Y. Y a n g
Memorial Sloan-Kettering Cancer Center, New York, N Y To obtain more sequence dam and biochemical chara~ristics of HLA-C antigens, a cDNA library made from an individual with HLA-Cw6 and -Cw8 was screened with a C locus-specific probe. One full-length eDNA was ¢ransfeated into mouse L ceUs and expressed on the cell surface. One-dimensional IEF analysis of samples obtained from the transfectants using W6/32 monocloual antibody showed that this gene encoded the Cw6 antigen. Interestingly, two bands were observed on an IEF gel but the uppermost band of the three Cw6 bands found in paternal cells was m i s d ~ This indicates that at least some of the multiplicities of C antigens ate the result ofposmansladonal modifications. Predicted amino acid sequences of the C v ~ antigens revealed dose s;mlhrltles to those of Cwl, - C w 2 , and - C w 3 antigens. All amino acid residues comidered to he C locus specific were conserved (Val-52, Glu-182, His-183, and Gin-268). Except for three unique amino acid ~sidues found in Cw6, all other residues in extracellu~ doma;n~ were found in either Cwl or -Cw2 proteins. This may indim~e the importance of recombination or exchange events between C alleles in the generation of polymorlphisms.
125
(122) P r e d i c t a b i l i t y o f D T T C r o s s M e t c h M.IL Mickey, M. Lau, B. Carnahan, and P.I. Ternsaki
UCLA Tissue Typing Laboratory, UCLA, Los Angeles, CA Kidneys shipped for pteseleceed patients are often transplanted into others because of positive crossmatch. We have been interested in computer p:edicdon of crossmatch to a~oki most of the mhdirection. The prediction is based on panel pretesting of recipient sera and the HLA type of the donor. We sought to eliminsre the prediction errors av.ributable to non-HLA cytotoxic antibodies by pretreatment of sera with DTi'. We res~ed the prediction in a laboratory study in which prediction equations for 116 sera from waiting patients were based nn a frozen panel of 140 cells and applied to predicting test outcome for t38 simulated donor cells. Ninety-six percent of all psedkdons of negative test outcome were correct for D T r and 91% were correct for the same sera without DTI'. Few negative predictions were made for sera with 90%-100% PRA end only about half were correct. For ? 0 % - 9 0 ~ PILA, 89% were correct with DTI" and 82% for controh. For sere |tom candidates for first TX, 93% of negative predictions were correct for 7 0 % - 9 0 % PRA compared to 83% for candidates fog re-transplant. We conclude that negative crossmatch outcome can now he predicted acceptably well for patients with PRA less than 90%, a practically imporumt achievement. More work is requited to eliminate s e n exchange for the very highly sensitized patients.
(123) D N A T e c h n i q u e s i n T i s s u e T y p i n g D. Middleton, D . Savage, C. O'Neill, and J. Martin
Northern lrdand Tissue Typing Service, BdfaJt, Irdand We have D N A RFLP typed 160 renal patients either transplanted or awaiting a transplant to compare the results obtained to those of convenfio~ml serolng/c typing. The restriction enzyme Te~qland probes for HI.A-DR/3, I-ILA-DQ~, and HLA-DQ~ genes were used. The serologic ,'ype differed from the RFIL.._?type in 27 (17%) of patients. In 5 ~ t i e n t s an incorrect antigen has been assigned by serology and in 22 patients an antigen detected by RFLP was not detected by serology. In add/don, RFLP techniques have enabled the splitting of DR5 and DR6, antigens for which it is difficult to obtain suitable sera, and to split DB3 and DRT, antigens that previously were thought not to have splits. R~suhs will be presented o f the frequency o f these splits. their association with HLA-B locus antigens and the relationship of variants Of DRw52 to these splits. The use of RFLP has also allowed the determination of D Q antigens and the delin~t/on of new splits at this locus. O n only two occasions, due to poor D N A yields, was a repest sample requ/red for RFLP typing. In contrast 44% of patients had to he serologicaBy ~ on at least t~0 occasions, indeed the a v e r s e number of typiegs for each patient was 1.9. Other advantages offered by RFLP are the ability to type samples up to 7 days old and to confirm homozygosity without reference to family members, 17% of patients were found to be homozygous.
(124) I s o l a t i o n a n d E x p r e s s i o n o f a c D N A C l o n e E n c o d i n g a n H L A - C w 6 G e n e S. M i z u n o , S. g a n g , H , Lee, J,A. Trap~fi, and S.Y. Y a n g
Memorial Sloan-Kettering Cancer Center, New York, N Y To obtain more sequence dam and biochemical chara~ristics of HLA-C antigens, a cDNA library made from an individual with HLA-Cw6 and -Cw8 was screened with a C locus-specific probe. One full-length eDNA was ¢ransfeated into mouse L ceUs and expressed on the cell surface. One-dimensional IEF analysis of samples obtained from the transfectants using W6/32 monocloual antibody showed that this gene encoded the Cw6 antigen. Interestingly, two bands were observed on an IEF gel but the uppermost band of the three Cw6 bands found in paternal cells was m i s d ~ This indicates that at least some of the multiplicities of C antigens ate the result ofposmansladonal modifications. Predicted amino acid sequences of the C v ~ antigens revealed dose s;mlhrltles to those of Cwl, - C w 2 , and - C w 3 antigens. All amino acid residues comidered to he C locus specific were conserved (Val-52, Glu-182, His-183, and Gin-268). Except for three unique amino acid ~sidues found in Cw6, all other residues in extracellu~ doma;n~ were found in either Cwl or -Cw2 proteins. This may indim~e the importance of recombination or exchange events between C alleles in the generation of polymorlphisms.