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68-P
S100
Abstracts
67-P
SERACLEAN – A NEW PRODUCT FOR DEALING WITH HIGH CONTROL VALUES SEEN IN THE LUMINEX ASSAY Anna J. Danskine, John D. Smith, Rachel E. Fawson, Helen Newell, Marlene L. Rose. Tissue Typing Department, Harefield Hospital, Harefield, Middlesex, United Kingdom Aim: Clinically, donor-recipient selection relies on accurate antibody identification to prevent humoral rejection following transplantation. In comparison with other techniques the Luminex assay gives improved sensitivity and antibody definition, however some samples remain a problem due to high control values, which may give a false negative result. Seraclean (Tepnel) has been developed to improve testing of such samples, by preliminary adsorption to remove material non-specifically bound to the LIFEMATCH™ antibody beads. Methods: Seraclean pre-treatment requires 20ml of serum to be incubated with 4ml of Seraclean for 30mins at room temperature. The sample is centrifuged and 12.5ml of serum aspirated for use in a LIFEMATCH™ assay. We treated 46 patient samples, previously found to have high control values, with Seraclean and tested them pre- and post-treatment in the LIFESCREEN antibody screening assay (Tepnel). We also treated 14 samples from patients with HLA Class I antibodies and 11 samples from patients with HLA Class II antibodies, of which 12 and 9 respectively had previously presented with high control values. These sera were tested pre- and post- Seraclean treatment in the LIFEMATCH™ Class I and Class II ID assays. Scope: 33 of 46 samples tested in the screening assay had high control values prior to treatment, of these 26 (79%) were reduced to within the normal range following treatment. 5 of 7 samples in which control values remained high were from patients who had received LVAD implants and have been shown to have anti-albumin antibodies. 13 of 25 samples tested for class I or class II antibodies presented with high control values and of these, 8 (62%) had improved antibody definition. 7 of the 12 samples (58%) that had control values within the normal range also had improved antibody definition following Seraclean treatment. Conclusions: We have shown that Seraclean pre-treatment of samples with high control values improves accuracy and sensitivity of Luminex assays by reducing non-specific binding, and can have an effect even when control values are within the normal range.
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IS THE TIME LENGTH FROM TRANSPLANTATION TO GRAFT LOSS CORRELATED TO THE QUANTITY OF HLA MATCHMAKER MISMATCHES CLASS I AND II IN POSTTRANSPLANTED PATIENTS? Helena B. Cazarote, Karina Omairi, Carlos A. Fernandes, Josemere H. Lima, Cristina vonGlehn. Laboratorio de Imunogenetica, Pontificia Universidade Catolica do Parana, Curitiba, Parana, Brazil Aim: HLA matchmaker is a computer-based algorithm that determines donor-recipient HLA compatibility at the molecular level, comparing the amino acid triplets on exposed parts of proteins sequences accessible to alloantibodies. Methods: We studied 28 transplanted patients from July 2000 to July 2005 who underwent graft loss, 14 of these transplants were with cadaver donors and 14 with alive donors (13 men and 15 women). All patients were cross-match negative by CDC test. Five patients had lost their graft in the first 15 days after transplantation, ten had lost it in 1 to 5 months, seven had lost it in 6 to 9 months and six had lost it after one year of transplantation. We compared the number of mismatches with the time length from transplantation to graft loss by the statistic method of Pearson⬘s Coefficient of Correlation and studied the number of mismatches found in patient and donor comparison by HLA matchmaker analysis. Scope: The aim of this study was to discover if the number of immunogenic epitopes can influence the time length from transplantation to graft failure and measure this correlation, even though we had already known that there are many other factors that could influence the rejection of the graft. Conclusions: Analyzing the match considering patient and donor we found 21 samples that were full mismatch for both classes I and II, 5 samples that only had match for class II, 1 sample that only had match for class I and 1 sample that was full match for both classes. Using the Pearson⬘s Coefficient of Correlation to compare the time length from transplantation to graft loss and the number of mismatches we found a moderate negative correlation for both cases in which we had for class I - 0,50 and for class II -0,39. The negative correlation means that the higher the quantity of mismatches, the greater the chances of graft loss. In our sample, we verified that the chances of graft loss are even greater if the mismatches were for class I.
Abstracts
67-P
SERACLEAN – A NEW PRODUCT FOR DEALING WITH HIGH CONTROL VALUES SEEN IN THE LUMINEX ASSAY Anna J. Danskine, John D. Smith, Rachel E. Fawson, Helen Newell, Marlene L. Rose. Tissue Typing Department, Harefield Hospital, Harefield, Middlesex, United Kingdom Aim: Clinically, donor-recipient selection relies on accurate antibody identification to prevent humoral rejection following transplantation. In comparison with other techniques the Luminex assay gives improved sensitivity and antibody definition, however some samples remain a problem due to high control values, which may give a false negative result. Seraclean (Tepnel) has been developed to improve testing of such samples, by preliminary adsorption to remove material non-specifically bound to the LIFEMATCH™ antibody beads. Methods: Seraclean pre-treatment requires 20ml of serum to be incubated with 4ml of Seraclean for 30mins at room temperature. The sample is centrifuged and 12.5ml of serum aspirated for use in a LIFEMATCH™ assay. We treated 46 patient samples, previously found to have high control values, with Seraclean and tested them pre- and post-treatment in the LIFESCREEN antibody screening assay (Tepnel). We also treated 14 samples from patients with HLA Class I antibodies and 11 samples from patients with HLA Class II antibodies, of which 12 and 9 respectively had previously presented with high control values. These sera were tested pre- and post- Seraclean treatment in the LIFEMATCH™ Class I and Class II ID assays. Scope: 33 of 46 samples tested in the screening assay had high control values prior to treatment, of these 26 (79%) were reduced to within the normal range following treatment. 5 of 7 samples in which control values remained high were from patients who had received LVAD implants and have been shown to have anti-albumin antibodies. 13 of 25 samples tested for class I or class II antibodies presented with high control values and of these, 8 (62%) had improved antibody definition. 7 of the 12 samples (58%) that had control values within the normal range also had improved antibody definition following Seraclean treatment. Conclusions: We have shown that Seraclean pre-treatment of samples with high control values improves accuracy and sensitivity of Luminex assays by reducing non-specific binding, and can have an effect even when control values are within the normal range.
68-P
IS THE TIME LENGTH FROM TRANSPLANTATION TO GRAFT LOSS CORRELATED TO THE QUANTITY OF HLA MATCHMAKER MISMATCHES CLASS I AND II IN POSTTRANSPLANTED PATIENTS? Helena B. Cazarote, Karina Omairi, Carlos A. Fernandes, Josemere H. Lima, Cristina vonGlehn. Laboratorio de Imunogenetica, Pontificia Universidade Catolica do Parana, Curitiba, Parana, Brazil Aim: HLA matchmaker is a computer-based algorithm that determines donor-recipient HLA compatibility at the molecular level, comparing the amino acid triplets on exposed parts of proteins sequences accessible to alloantibodies. Methods: We studied 28 transplanted patients from July 2000 to July 2005 who underwent graft loss, 14 of these transplants were with cadaver donors and 14 with alive donors (13 men and 15 women). All patients were cross-match negative by CDC test. Five patients had lost their graft in the first 15 days after transplantation, ten had lost it in 1 to 5 months, seven had lost it in 6 to 9 months and six had lost it after one year of transplantation. We compared the number of mismatches with the time length from transplantation to graft loss by the statistic method of Pearson⬘s Coefficient of Correlation and studied the number of mismatches found in patient and donor comparison by HLA matchmaker analysis. Scope: The aim of this study was to discover if the number of immunogenic epitopes can influence the time length from transplantation to graft failure and measure this correlation, even though we had already known that there are many other factors that could influence the rejection of the graft. Conclusions: Analyzing the match considering patient and donor we found 21 samples that were full mismatch for both classes I and II, 5 samples that only had match for class II, 1 sample that only had match for class I and 1 sample that was full match for both classes. Using the Pearson⬘s Coefficient of Correlation to compare the time length from transplantation to graft loss and the number of mismatches we found a moderate negative correlation for both cases in which we had for class I - 0,50 and for class II -0,39. The negative correlation means that the higher the quantity of mismatches, the greater the chances of graft loss. In our sample, we verified that the chances of graft loss are even greater if the mismatches were for class I.