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SALT LAKE CITY – The presence of p2X7 receptor single nucleotide polymorphisms (SNPs) associated with gain and loss of function may help predict outcomes after allogeneic stem cell transplantation, according to findings from a clinical correlate analysis of recipient and donor DNA samples.
The findings require validation in future studies, but suggest that the presence of the SNPs and p2X7 haplotypes 2 and 4 could be incorporated into disease risk models to improve transplant decision making, David Stuart Ritchie, MD, reported at the combined annual meetings of the Center for International Blood & Marrow Transplant Research and the American Society for Blood and Marrow Transplantation.
The analysis, which specifically looked for the presence of 16 previously identified SNPs and the haplotypes 2 and 4 in p2x7, was performed on pretransplant DNA samples from 333 allogeneic stem cell transplant recipients and 228 donors at a single center between 2002 and 2013. The findings were correlated with patient outcomes.
Five SNPs were excluded from correlation because of low frequency, and of the 11 remaining SNPs, 3 were found to be significantly associated with reduced incidence of acute and/or chronic graft-versus-host disease (GVHD), and 2 were significantly associated with increased relapse or transplant-related mortality, said Dr. Ritchie of the University of Melbourne, Parkville, Australia.
The loss-of-function SNPs rs28360457 and rs3751133 – each linked with decreased inflammation – were significantly associated with a reduced incidence of acute GVHD when comparing grade 0 with grades 1-4 GVHD (P = .0234 and P = .0411, respectively), but not when comparing grades 0-1 and grades 2-4 GVHD.
SNP rs3751133 was also significantly associated with reduced incidence of chronic GVHD when comparing grade 0 with grades 0-4 GVHD (P = .01), but not when comparing grades 0-1 and grades 2-4 GVHD, he said.
The loss-of-function SNP rs1653624 – which is linked with decreased phagocytosis – was associated with an increased incidence of acute GVHD when comparing grade 0 vs. grade 1-4 GVHD (P = .01), but not when comparing grades 0-1 and grades 2-4 GVHD (P = NS).
SNP rs7958311, which had increased surface expression, was associated with a trend toward increased relapse risk (P = .053), and the loss-of-function SNP rs1653624 was associated with an excess of early transplant-related mortality (P = .0471).
“Individual SNPs are interesting, but perhaps more interesting are the haplotypes,” Dr. Ritchie said.
Haplotype 4, which was found in 8 recipients, involves rs1718119 and rs7958311. Those SNPs were previously shown to have 300% and 195% increased expression, respectively, with or without rs2230912, which has been shown to be decreased by 72%, and with or without loss of function rs1653624. Haplotype 4 is associated with a net increase in p2X7 activity, he explained.
In the current study, haplotype 4 was only found to involve rs1718119 co-inherited with rs2230912, and was associated with substantially decreased relapse-free survival overall (hazard ratio, 0.6946), when compared with haplotype 2 (HR, 0.2078), he said.
The differences between haplotype 4 and haplotype 2, and between haplotype 4 and patients with neither haplotype, were highly statistically significant.
Relapse-free survival did not differ significantly between those with haplotype 2 and those with neither haplotype (HR, 0.7717). Similarly, overall survival was significantly poorer among those with haplotype 4 versus haplotype 2 or no haplotype (HR, 0.2812 and 0.2882, respectively), but no difference was seen in overall survival between those with haplotype 2 and those with no haplotype (HR, 1.003), he said.
P2X7 is a purinergic signaling receptor located at chromosome 12q24–a region associated with inflammatory disorders. It plays an important role in immunogenic cell death. It is expressed in all leukocytes, with the highest level of expression seen in monocyte lineage. Binding of its ligand – extracellular adenosine 5’-triphosphate – leads to activation of dendritic cells and release of IL1b leading to T cell recruitment and the production of memory T cells.
Both gain- and loss-of-function SNPs in p2X7 have been reported and implicated in GVHD and other inflammatory disorders, Dr. Ritchie said, explaining the rationale for studying their correlations with outcomes after allogeneic stem cell transplantation.
While such transplants are highly effective for treating hematologic malignancies, outcomes can be adversely affected by infection, acute organ dysfunction, and GVHD. Pretransplant conditioning regimens are associated with high levels of immunogenic cell death and the release of extracellular adenosine 5’-triphosphate, therefore signaling through the p2X7 receptor may lead to activation of downstream effectors that influence transplant outcome, he noted.
“We hypothesized that germline gain or loss of function polymorphisms in this receptor in recipients of allogeneic transplantation would result in an adverse outcome,” he said.
The mean age of the recipients whose samples were analyzed was 46 years, and about half were women. Most (83.8%) had a peripheral blood graft source and 64% of transplants were from related donors. The nonrelapse mortality at 24 months was 12.98%, Dr. Ritchie said, noting that their indications for transplantation were “fairly representative of the adult transplant population, dominated by acute leukemia with a range of other acute conditions.”
The findings – particularly those with respect to haplotype 4, which had the most substantial impact – could play a role in patient risk assessment.
“Potentially, although it is a relatively uncommon haplotype, pretransplant identification of haplotype 4 may well have implications for transplant decision making, given the fact that the majority of our patients with this haplotype did not survive posttransplant,” he concluded, noting that an effort to validate the findings is ongoing in an additional 300 patients.
Dr. Ritchie reported having no financial disclosures.
SOURCE: Koldej R et al. The 2018 BMT Tandem Meetings, Abstract 22.
SALT LAKE CITY – The presence of p2X7 receptor single nucleotide polymorphisms (SNPs) associated with gain and loss of function may help predict outcomes after allogeneic stem cell transplantation, according to findings from a clinical correlate analysis of recipient and donor DNA samples.
The findings require validation in future studies, but suggest that the presence of the SNPs and p2X7 haplotypes 2 and 4 could be incorporated into disease risk models to improve transplant decision making, David Stuart Ritchie, MD, reported at the combined annual meetings of the Center for International Blood & Marrow Transplant Research and the American Society for Blood and Marrow Transplantation.
The analysis, which specifically looked for the presence of 16 previously identified SNPs and the haplotypes 2 and 4 in p2x7, was performed on pretransplant DNA samples from 333 allogeneic stem cell transplant recipients and 228 donors at a single center between 2002 and 2013. The findings were correlated with patient outcomes.
Five SNPs were excluded from correlation because of low frequency, and of the 11 remaining SNPs, 3 were found to be significantly associated with reduced incidence of acute and/or chronic graft-versus-host disease (GVHD), and 2 were significantly associated with increased relapse or transplant-related mortality, said Dr. Ritchie of the University of Melbourne, Parkville, Australia.
The loss-of-function SNPs rs28360457 and rs3751133 – each linked with decreased inflammation – were significantly associated with a reduced incidence of acute GVHD when comparing grade 0 with grades 1-4 GVHD (P = .0234 and P = .0411, respectively), but not when comparing grades 0-1 and grades 2-4 GVHD.
SNP rs3751133 was also significantly associated with reduced incidence of chronic GVHD when comparing grade 0 with grades 0-4 GVHD (P = .01), but not when comparing grades 0-1 and grades 2-4 GVHD, he said.
The loss-of-function SNP rs1653624 – which is linked with decreased phagocytosis – was associated with an increased incidence of acute GVHD when comparing grade 0 vs. grade 1-4 GVHD (P = .01), but not when comparing grades 0-1 and grades 2-4 GVHD (P = NS).
SNP rs7958311, which had increased surface expression, was associated with a trend toward increased relapse risk (P = .053), and the loss-of-function SNP rs1653624 was associated with an excess of early transplant-related mortality (P = .0471).
“Individual SNPs are interesting, but perhaps more interesting are the haplotypes,” Dr. Ritchie said.
Haplotype 4, which was found in 8 recipients, involves rs1718119 and rs7958311. Those SNPs were previously shown to have 300% and 195% increased expression, respectively, with or without rs2230912, which has been shown to be decreased by 72%, and with or without loss of function rs1653624. Haplotype 4 is associated with a net increase in p2X7 activity, he explained.
In the current study, haplotype 4 was only found to involve rs1718119 co-inherited with rs2230912, and was associated with substantially decreased relapse-free survival overall (hazard ratio, 0.6946), when compared with haplotype 2 (HR, 0.2078), he said.
The differences between haplotype 4 and haplotype 2, and between haplotype 4 and patients with neither haplotype, were highly statistically significant.
Relapse-free survival did not differ significantly between those with haplotype 2 and those with neither haplotype (HR, 0.7717). Similarly, overall survival was significantly poorer among those with haplotype 4 versus haplotype 2 or no haplotype (HR, 0.2812 and 0.2882, respectively), but no difference was seen in overall survival between those with haplotype 2 and those with no haplotype (HR, 1.003), he said.
P2X7 is a purinergic signaling receptor located at chromosome 12q24–a region associated with inflammatory disorders. It plays an important role in immunogenic cell death. It is expressed in all leukocytes, with the highest level of expression seen in monocyte lineage. Binding of its ligand – extracellular adenosine 5’-triphosphate – leads to activation of dendritic cells and release of IL1b leading to T cell recruitment and the production of memory T cells.
Both gain- and loss-of-function SNPs in p2X7 have been reported and implicated in GVHD and other inflammatory disorders, Dr. Ritchie said, explaining the rationale for studying their correlations with outcomes after allogeneic stem cell transplantation.
While such transplants are highly effective for treating hematologic malignancies, outcomes can be adversely affected by infection, acute organ dysfunction, and GVHD. Pretransplant conditioning regimens are associated with high levels of immunogenic cell death and the release of extracellular adenosine 5’-triphosphate, therefore signaling through the p2X7 receptor may lead to activation of downstream effectors that influence transplant outcome, he noted.
“We hypothesized that germline gain or loss of function polymorphisms in this receptor in recipients of allogeneic transplantation would result in an adverse outcome,” he said.
The mean age of the recipients whose samples were analyzed was 46 years, and about half were women. Most (83.8%) had a peripheral blood graft source and 64% of transplants were from related donors. The nonrelapse mortality at 24 months was 12.98%, Dr. Ritchie said, noting that their indications for transplantation were “fairly representative of the adult transplant population, dominated by acute leukemia with a range of other acute conditions.”
The findings – particularly those with respect to haplotype 4, which had the most substantial impact – could play a role in patient risk assessment.
“Potentially, although it is a relatively uncommon haplotype, pretransplant identification of haplotype 4 may well have implications for transplant decision making, given the fact that the majority of our patients with this haplotype did not survive posttransplant,” he concluded, noting that an effort to validate the findings is ongoing in an additional 300 patients.
Dr. Ritchie reported having no financial disclosures.
SOURCE: Koldej R et al. The 2018 BMT Tandem Meetings, Abstract 22.
SALT LAKE CITY – The presence of p2X7 receptor single nucleotide polymorphisms (SNPs) associated with gain and loss of function may help predict outcomes after allogeneic stem cell transplantation, according to findings from a clinical correlate analysis of recipient and donor DNA samples.
The findings require validation in future studies, but suggest that the presence of the SNPs and p2X7 haplotypes 2 and 4 could be incorporated into disease risk models to improve transplant decision making, David Stuart Ritchie, MD, reported at the combined annual meetings of the Center for International Blood & Marrow Transplant Research and the American Society for Blood and Marrow Transplantation.
The analysis, which specifically looked for the presence of 16 previously identified SNPs and the haplotypes 2 and 4 in p2x7, was performed on pretransplant DNA samples from 333 allogeneic stem cell transplant recipients and 228 donors at a single center between 2002 and 2013. The findings were correlated with patient outcomes.
Five SNPs were excluded from correlation because of low frequency, and of the 11 remaining SNPs, 3 were found to be significantly associated with reduced incidence of acute and/or chronic graft-versus-host disease (GVHD), and 2 were significantly associated with increased relapse or transplant-related mortality, said Dr. Ritchie of the University of Melbourne, Parkville, Australia.
The loss-of-function SNPs rs28360457 and rs3751133 – each linked with decreased inflammation – were significantly associated with a reduced incidence of acute GVHD when comparing grade 0 with grades 1-4 GVHD (P = .0234 and P = .0411, respectively), but not when comparing grades 0-1 and grades 2-4 GVHD.
SNP rs3751133 was also significantly associated with reduced incidence of chronic GVHD when comparing grade 0 with grades 0-4 GVHD (P = .01), but not when comparing grades 0-1 and grades 2-4 GVHD, he said.
The loss-of-function SNP rs1653624 – which is linked with decreased phagocytosis – was associated with an increased incidence of acute GVHD when comparing grade 0 vs. grade 1-4 GVHD (P = .01), but not when comparing grades 0-1 and grades 2-4 GVHD (P = NS).
SNP rs7958311, which had increased surface expression, was associated with a trend toward increased relapse risk (P = .053), and the loss-of-function SNP rs1653624 was associated with an excess of early transplant-related mortality (P = .0471).
“Individual SNPs are interesting, but perhaps more interesting are the haplotypes,” Dr. Ritchie said.
Haplotype 4, which was found in 8 recipients, involves rs1718119 and rs7958311. Those SNPs were previously shown to have 300% and 195% increased expression, respectively, with or without rs2230912, which has been shown to be decreased by 72%, and with or without loss of function rs1653624. Haplotype 4 is associated with a net increase in p2X7 activity, he explained.
In the current study, haplotype 4 was only found to involve rs1718119 co-inherited with rs2230912, and was associated with substantially decreased relapse-free survival overall (hazard ratio, 0.6946), when compared with haplotype 2 (HR, 0.2078), he said.
The differences between haplotype 4 and haplotype 2, and between haplotype 4 and patients with neither haplotype, were highly statistically significant.
Relapse-free survival did not differ significantly between those with haplotype 2 and those with neither haplotype (HR, 0.7717). Similarly, overall survival was significantly poorer among those with haplotype 4 versus haplotype 2 or no haplotype (HR, 0.2812 and 0.2882, respectively), but no difference was seen in overall survival between those with haplotype 2 and those with no haplotype (HR, 1.003), he said.
P2X7 is a purinergic signaling receptor located at chromosome 12q24–a region associated with inflammatory disorders. It plays an important role in immunogenic cell death. It is expressed in all leukocytes, with the highest level of expression seen in monocyte lineage. Binding of its ligand – extracellular adenosine 5’-triphosphate – leads to activation of dendritic cells and release of IL1b leading to T cell recruitment and the production of memory T cells.
Both gain- and loss-of-function SNPs in p2X7 have been reported and implicated in GVHD and other inflammatory disorders, Dr. Ritchie said, explaining the rationale for studying their correlations with outcomes after allogeneic stem cell transplantation.
While such transplants are highly effective for treating hematologic malignancies, outcomes can be adversely affected by infection, acute organ dysfunction, and GVHD. Pretransplant conditioning regimens are associated with high levels of immunogenic cell death and the release of extracellular adenosine 5’-triphosphate, therefore signaling through the p2X7 receptor may lead to activation of downstream effectors that influence transplant outcome, he noted.
“We hypothesized that germline gain or loss of function polymorphisms in this receptor in recipients of allogeneic transplantation would result in an adverse outcome,” he said.
The mean age of the recipients whose samples were analyzed was 46 years, and about half were women. Most (83.8%) had a peripheral blood graft source and 64% of transplants were from related donors. The nonrelapse mortality at 24 months was 12.98%, Dr. Ritchie said, noting that their indications for transplantation were “fairly representative of the adult transplant population, dominated by acute leukemia with a range of other acute conditions.”
The findings – particularly those with respect to haplotype 4, which had the most substantial impact – could play a role in patient risk assessment.
“Potentially, although it is a relatively uncommon haplotype, pretransplant identification of haplotype 4 may well have implications for transplant decision making, given the fact that the majority of our patients with this haplotype did not survive posttransplant,” he concluded, noting that an effort to validate the findings is ongoing in an additional 300 patients.
Dr. Ritchie reported having no financial disclosures.
SOURCE: Koldej R et al. The 2018 BMT Tandem Meetings, Abstract 22.
REPORTING FROM THE 2018 BMT TANDEM MEETINGS
Key clinical point:
Major finding: Haplotype 4 was associated with substantially decreased relapse-free survival overall (hazard ratio, 0.6946) versus haplotype 2 (HR, 0.2078).
Study details: A clinical correlate analysis of 561 DNA samples.
Disclosures: Dr. Ritchie reported having no financial disclosures.
Source: Koldej R et al. The 2018 BMT Tandem Meetings, Abstract 22.