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170: Gene expression profiling distinguishes moderate to severe from mild acute cellular rejection in cardiac allograft recipients
The Journal of Heart and Lung Transplantation Volume 26, Number 2S
Results: Of the 130 patients, 67 patients had 124 BNP measurements with a PCWP ⱖ15. The BNP was ⱖ150 pg/ml in only 42 of 124 (33.8%) measurements. In 29 patients with symptomatic heart failure and PCWP ⱖ15, the BNP was ⱖ150 on only 19 of 42 (45.2%) occasions. Therefore, a BNP level of ⱖ150 was found to have a sensitivity of only 45.2%, a specificity of 64.9%, a positive predictive value of 3.7%, and a negative predictive value of 2.4% for the detection of heart failure in heart transplant recipients. In addition, a BNP value ⱖ150 within 8 weeks of a clinically significant episode of rejection was noted in only 5 of 10 (50%) cases. Conclusions: BNP levels are not effective in determining clinically relevant heart failure following heart transplantation. In addition, it does not appear to predict rejection. The discrepancy between the utility of BNP in detecting heart failure in the transplant and nontransplant population may be due to denervated cardiac physiology but requires further investigation.
170 GENE EXPRESSION PROFILING DISTINGUISHES MODERATE TO SEVERE FROM MILD ACUTE CELLULAR REJECTION IN CARDIAC ALLOGRAFT RECIPIENTS D. Bernstein,1 G. Berry,1 M. Billingham,1 C.C. Marboe,2 M.C. Deng,2 S. Mital,2 H. Eisen,3 G.E. Williams,4 H. Baron,4 T.M. Klingler,4 J.G. Wohlgemuth,4 J. Kobashigawa,5 1Stanford University, Stanford, CA; 2Columbia University, New York, NY; 3 Hahnemann University Hospital, Philadelphia, PA; 4XDx, South San Francisco, CA; 5University of California, Los Angeles, Los Angeles, CA Purpose: Gene expression (GE) profiling of PBMCs distinguishes between the absence (grade 0) or presence of moderate to severe (grades ⱖ3A) acute cellular rejection (ACR) in cardiac allograft recipients using the 20-gene rt-PCR-based AlloMap molecular expression test. We explored the hypothesis that the gene algorithm also differentiates mild ACR, and performed subanalyses based on time post-transplant (p-tx) and confirmatory pathology interpretations. Methods and Materials: A post hoc analysis of 265 CARGO Study patients and 714 clinical encounters used inclusion criteria of: ⬎55 d p-tx, ⬎21 d after ACR therapy, biopsy grade and AlloMap GE score. Biopsy grades assigned by a study center pathologist (local) were re-interpreted by three pathologists (central) in a blinded manner. Results: Mean GE scores (⫾SE) not only differentiated grades ⱖ3A from grade 0 (p⬍0.00001, local or central), but also from grades 1A or 2 (p⬍0.05, local or central). Data showed mean GE scores for grade 1B and grades ⱖ3A to be 29.7⫾1.1 and 30.7⫾0.9 (p⫽0.49, local) or 29.8⫾2.0 and 32⫾0.9 (p⫽0.25, central), respectively, thus substantiating our prior work showing their molecular similarity (Bernstein et al. JHLT. 2005.24:S65). Subgroup analyses of encounters from 2 to 6 mos or ⬎6 mos p-tx showed mean GE scores for grades ⱖ3A of 30.8⫾1.4 or 33.5⫾1.0, respectively, with discrimination from grades 0, 1A or 2 (p⬍0.001 (2 to 6 mos) or p⬍0.03 (⬎6 mos)), but not 1B (central). Mean GE scores for all central-confirmed grade 0 (25.3⫾0.5, n⫽176) differed from those re-assigned to grades ⱖ1A (28.3⫾1.1, n⫽25) (p⫽0.023), while those for all central-confirmed gradesⱖ3A (32.0⫾0.9, n⫽24) differed from those re-assigned to grades ⬍3A (25.7⫾3.3, n⫽5) (p⫽0.014). Conclusions: These data demonstrate that a) AlloMap GE scores discriminate grades ⱖ3A from grades 1A and 2; b) early and late grades ⱖ3A ACR demonstrate different mean GE scores; and c) GE scores correlate with both central confirmed and re-classified biopsy grades, thus providing novel molecular insights into ACR risk. XDx has provided research support for the CARGO Study; XDx.
Abstracts
S121
171 DOES INDUCTION THERAPY INFLUENCE THE UTILITY OF GENE EXPRESSION TESTING FOR CARDIAC ALLOGRAFT REJECTION? M. Mehra,1 M.C. Deng,2 R. Starling,3 S. Murali,4 D. Pauly,5 P. Lal,6 M. Cadeiras,2 H. Baron,6 S. Rosenberg,6 H. Eisen,7 1University of Maryland, Baltimore, MD; 2Columbia University Medical Center, New York, NY; 3Cleveland Clinical, Cleveland, OH; 4Allegheny General Hospital, Pittsburgh, PA; 5University of Florida, Gainesville, FL; 6XDx, South San Francisco, CA; 7Drexel University College of Medicine, Philadelphia, PA Purpose: The AlloMap molecular expression test assesses the acute cellular rejection (ACR) status of cardiac allograft recipients based on RT-PCR of 11 informative genes from diverse molecular pathways and 9 normalization and control genes. The test’s high negative predictive value can be used to reliably exclude ACR in stable transplant recipients beyond 2 mos post-transplant (p-tx). Whether induction therapy (IT), which alters activation and levels of circulating effector cells, might alter the interpretation of alloimmune gene expression within the first 6 months p-tx remains uncertain. Methods and Materials: We performed a post hoc analysis on a patient cohort from the CARGO database by selecting 52 patients within 6 mos p-tx and dividing them into two groups: group I (n⫽31, IT group: anti-thymocyte globulin (ATG), daclizumab (DAC) or OKT3), or group II (n⫽21, no IT group). The primary outcomes assessed were a) the AlloMap test scores (0 to 40 scale) and b) the cycle threshold (Ct) values for the 11 individual informative genes in the algorithm. Results: Patients in group I received IT as follows: (ATG, n⫽1; DAC, n⫽26; OKT3, n⫽4, while the control group II included 21 patients. The earliest blood samples for patients with (n⫽31) and without (n⫽21) IT showed no difference in either mean AlloMap scores (18.9 and 17.8, p⫽0.66, respectively) or mean Ct values reflecting the gene expression levels of the individual 11 algorithm genes. The two groups did not differ in days p-tx (77 vs. 66, p⫽0.40) or steroid dose (prednisone 18 vs. 16 mg, p⫽0.50). Conclusions: Despite the known effects of induction therapy on circulating immune effector cells, we found no effects of such therapy on either the AlloMap test score or the expression of its individual constituent genes. The lack of IT effects likely results from the inclusion of patients from all CARGO Study centers, regardless of IT usage protocols, during algorithm development. These data suggest that interpretation of test scores within 6 mos p-tx may occur independently of induction therapy status. 172 TIME LAPSE ANALYSIS OF CHANGES IN DOPPLER-DERIVED INDEX OF CORONARY FLOW RESERVE OVER TIME COULD REDUCE FREQUENCY OF ENDOMYOCARDIAL BIOPSY N. Oda,1 T.S. Kato,1 S. Hashimoto,1 C. Kamiya,1 K. Hashimura,1 A. Mano,1 H.I. Ueda,2 M. Kitakaze,1 T. Nakatani,3 1Department of Cardiovascular Medicine, National Cardiovascular Center, Suita, Osaka, Japan; 2Department of Pathology, National Cardiovascular Center, Suita, Osaka, Japan; 3Department of Transplantation, National Cardiovascular Center, Suita, Osaka, Japan Purpose: Invasive screenings for acute rejection by endomyocardial biopsy (EMB) in heart transplant recipients are still standard procedures. We assessed the clinical utility of echocardiographic detection of coronary artery flow reserve (CFR) as a noninvasive method for monitoring acute rejection in heart transplant recipients. Methods and Materials: In 30 transplant recipients (19 male, 11 female, 9 to 91 years old, 14days to 13 years posttransplant), 220
Results: Of the 130 patients, 67 patients had 124 BNP measurements with a PCWP ⱖ15. The BNP was ⱖ150 pg/ml in only 42 of 124 (33.8%) measurements. In 29 patients with symptomatic heart failure and PCWP ⱖ15, the BNP was ⱖ150 on only 19 of 42 (45.2%) occasions. Therefore, a BNP level of ⱖ150 was found to have a sensitivity of only 45.2%, a specificity of 64.9%, a positive predictive value of 3.7%, and a negative predictive value of 2.4% for the detection of heart failure in heart transplant recipients. In addition, a BNP value ⱖ150 within 8 weeks of a clinically significant episode of rejection was noted in only 5 of 10 (50%) cases. Conclusions: BNP levels are not effective in determining clinically relevant heart failure following heart transplantation. In addition, it does not appear to predict rejection. The discrepancy between the utility of BNP in detecting heart failure in the transplant and nontransplant population may be due to denervated cardiac physiology but requires further investigation.
170 GENE EXPRESSION PROFILING DISTINGUISHES MODERATE TO SEVERE FROM MILD ACUTE CELLULAR REJECTION IN CARDIAC ALLOGRAFT RECIPIENTS D. Bernstein,1 G. Berry,1 M. Billingham,1 C.C. Marboe,2 M.C. Deng,2 S. Mital,2 H. Eisen,3 G.E. Williams,4 H. Baron,4 T.M. Klingler,4 J.G. Wohlgemuth,4 J. Kobashigawa,5 1Stanford University, Stanford, CA; 2Columbia University, New York, NY; 3 Hahnemann University Hospital, Philadelphia, PA; 4XDx, South San Francisco, CA; 5University of California, Los Angeles, Los Angeles, CA Purpose: Gene expression (GE) profiling of PBMCs distinguishes between the absence (grade 0) or presence of moderate to severe (grades ⱖ3A) acute cellular rejection (ACR) in cardiac allograft recipients using the 20-gene rt-PCR-based AlloMap molecular expression test. We explored the hypothesis that the gene algorithm also differentiates mild ACR, and performed subanalyses based on time post-transplant (p-tx) and confirmatory pathology interpretations. Methods and Materials: A post hoc analysis of 265 CARGO Study patients and 714 clinical encounters used inclusion criteria of: ⬎55 d p-tx, ⬎21 d after ACR therapy, biopsy grade and AlloMap GE score. Biopsy grades assigned by a study center pathologist (local) were re-interpreted by three pathologists (central) in a blinded manner. Results: Mean GE scores (⫾SE) not only differentiated grades ⱖ3A from grade 0 (p⬍0.00001, local or central), but also from grades 1A or 2 (p⬍0.05, local or central). Data showed mean GE scores for grade 1B and grades ⱖ3A to be 29.7⫾1.1 and 30.7⫾0.9 (p⫽0.49, local) or 29.8⫾2.0 and 32⫾0.9 (p⫽0.25, central), respectively, thus substantiating our prior work showing their molecular similarity (Bernstein et al. JHLT. 2005.24:S65). Subgroup analyses of encounters from 2 to 6 mos or ⬎6 mos p-tx showed mean GE scores for grades ⱖ3A of 30.8⫾1.4 or 33.5⫾1.0, respectively, with discrimination from grades 0, 1A or 2 (p⬍0.001 (2 to 6 mos) or p⬍0.03 (⬎6 mos)), but not 1B (central). Mean GE scores for all central-confirmed grade 0 (25.3⫾0.5, n⫽176) differed from those re-assigned to grades ⱖ1A (28.3⫾1.1, n⫽25) (p⫽0.023), while those for all central-confirmed gradesⱖ3A (32.0⫾0.9, n⫽24) differed from those re-assigned to grades ⬍3A (25.7⫾3.3, n⫽5) (p⫽0.014). Conclusions: These data demonstrate that a) AlloMap GE scores discriminate grades ⱖ3A from grades 1A and 2; b) early and late grades ⱖ3A ACR demonstrate different mean GE scores; and c) GE scores correlate with both central confirmed and re-classified biopsy grades, thus providing novel molecular insights into ACR risk. XDx has provided research support for the CARGO Study; XDx.
Abstracts
S121
171 DOES INDUCTION THERAPY INFLUENCE THE UTILITY OF GENE EXPRESSION TESTING FOR CARDIAC ALLOGRAFT REJECTION? M. Mehra,1 M.C. Deng,2 R. Starling,3 S. Murali,4 D. Pauly,5 P. Lal,6 M. Cadeiras,2 H. Baron,6 S. Rosenberg,6 H. Eisen,7 1University of Maryland, Baltimore, MD; 2Columbia University Medical Center, New York, NY; 3Cleveland Clinical, Cleveland, OH; 4Allegheny General Hospital, Pittsburgh, PA; 5University of Florida, Gainesville, FL; 6XDx, South San Francisco, CA; 7Drexel University College of Medicine, Philadelphia, PA Purpose: The AlloMap molecular expression test assesses the acute cellular rejection (ACR) status of cardiac allograft recipients based on RT-PCR of 11 informative genes from diverse molecular pathways and 9 normalization and control genes. The test’s high negative predictive value can be used to reliably exclude ACR in stable transplant recipients beyond 2 mos post-transplant (p-tx). Whether induction therapy (IT), which alters activation and levels of circulating effector cells, might alter the interpretation of alloimmune gene expression within the first 6 months p-tx remains uncertain. Methods and Materials: We performed a post hoc analysis on a patient cohort from the CARGO database by selecting 52 patients within 6 mos p-tx and dividing them into two groups: group I (n⫽31, IT group: anti-thymocyte globulin (ATG), daclizumab (DAC) or OKT3), or group II (n⫽21, no IT group). The primary outcomes assessed were a) the AlloMap test scores (0 to 40 scale) and b) the cycle threshold (Ct) values for the 11 individual informative genes in the algorithm. Results: Patients in group I received IT as follows: (ATG, n⫽1; DAC, n⫽26; OKT3, n⫽4, while the control group II included 21 patients. The earliest blood samples for patients with (n⫽31) and without (n⫽21) IT showed no difference in either mean AlloMap scores (18.9 and 17.8, p⫽0.66, respectively) or mean Ct values reflecting the gene expression levels of the individual 11 algorithm genes. The two groups did not differ in days p-tx (77 vs. 66, p⫽0.40) or steroid dose (prednisone 18 vs. 16 mg, p⫽0.50). Conclusions: Despite the known effects of induction therapy on circulating immune effector cells, we found no effects of such therapy on either the AlloMap test score or the expression of its individual constituent genes. The lack of IT effects likely results from the inclusion of patients from all CARGO Study centers, regardless of IT usage protocols, during algorithm development. These data suggest that interpretation of test scores within 6 mos p-tx may occur independently of induction therapy status. 172 TIME LAPSE ANALYSIS OF CHANGES IN DOPPLER-DERIVED INDEX OF CORONARY FLOW RESERVE OVER TIME COULD REDUCE FREQUENCY OF ENDOMYOCARDIAL BIOPSY N. Oda,1 T.S. Kato,1 S. Hashimoto,1 C. Kamiya,1 K. Hashimura,1 A. Mano,1 H.I. Ueda,2 M. Kitakaze,1 T. Nakatani,3 1Department of Cardiovascular Medicine, National Cardiovascular Center, Suita, Osaka, Japan; 2Department of Pathology, National Cardiovascular Center, Suita, Osaka, Japan; 3Department of Transplantation, National Cardiovascular Center, Suita, Osaka, Japan Purpose: Invasive screenings for acute rejection by endomyocardial biopsy (EMB) in heart transplant recipients are still standard procedures. We assessed the clinical utility of echocardiographic detection of coronary artery flow reserve (CFR) as a noninvasive method for monitoring acute rejection in heart transplant recipients. Methods and Materials: In 30 transplant recipients (19 male, 11 female, 9 to 91 years old, 14days to 13 years posttransplant), 220