- Email: [email protected]
67-P: Low expressing IL-10 genotypes are associated with chronic allograft damage index (CADI) scores
Abstracts
S41
67-P
LOW EXPRESSING IL-10 GENOTYPES ARE ASSOCIATED WITH CHRONIC ALLOGRAFT DAMAGE INDEX (CADI) SCORES. Faisal M. Khan,1 Serdar Yilmaz,2 Aylin Sar,2 Jagdeep Doulla,1 Iwona Galaszkiewicz,1 Noureddine Berka.1 1Tissue Typing Lab, Calgary Laboratory Services, Calgary, AB, Canada; 2Medicine, University of Calgary, Calgary, AB, Canada. Aim: Chronic Allograft Damage Index (CADI) of the 6 month protocol core needle biopsy is a strong early predictor of long-term graft functioning. ‘Genetic predisposition’ of recipients to the heritable variants in the genes encoding cytokines is a compelling risk factor for high CADI score. In this study, we examined the association of SNPs in different cytokine genes with the composite CADI score and with each of the 8 individual histological indices. Methods: A total of 115 renal transplant recipients from Southern Alberta Renal Transplant program were genotyped for 15 SNPs located in 10 cytokine/cytokine receptor genes. Genotyping was done by Luminex based cytokine assay. Results: Genotypes with low expresing alleles at two promoter ‘SNPs’ of IL-10 gene, -592AA⫹AC (p⫽0.02;OR⫽2.82) and -819TT⫹TC (p⫽0.03;OR⫽2.6) were found to be associated with high CADI score. Expression profile based linear regression analysis also showed a good correlation with high CADI score (r ⫽0.43). At allelic levels,-592A allele (p⬍0.01) and -819T allele (p⫽0.01) also found strongly associated. At individual histological index, both -592AA⫹AC (p⫽0.002;OR⫽3.7) and -819TT⫹TC (p⫽0.004;OR⫽3.6) were found to be associated with interstitial fibrosis, while former also showed association with tubular atrophy (p⬍0.01;OR⫽4.2). Conclusions: (1) Kidney allograft recipients, genetically predisposed for low producing IL-10 genotypes are associated with high CADI scores. (2) A deficient regulatory milieu may be a crucial determinant of chronic allograft damage. (3) Cytokine genotyping as a predictive test along with the CADI scores may allow better anticipation of the clinical outcomes.
68-P
COMPLETE SEQUENCING OF HLA-DQA1 3’UTR AND CORRELATIONS WITH ANCESTRAL LINEAGES. Brittany A. Morrison, M. Tevfik Dorak. Genomic Immunoepidemiology Lab, HUMIGEN LLC, The Institute for Genetic Immunology, Hamilton, NJ, USA. Aim: HLA-DQA1 has been recognized as the most ancestral HLA locus. Two alleles of the HLA-DQA1 3’UTR SNP rs1142316 correlate with the most ancestral HLA class II lineages represented by DRB3 and DRB4. Individuals homozygous for different DQA1 alleles generate multiple DQA1 mRNA isoforms through a combination of alternative splicing acceptor and polyadenylation sites in their DQA1 3’UTR. We were interested in more detailed 3’UTR sequence information in “conserved extended haplotypes.”. Methods: We sequenced the whole 3’UTR in 31 IHWG cell lines. Results: We identified new polymorphisms in splicing donor/acceptor sites and polyadenylation sites. The variants at these sites cluster with ancestral lineages, in particular, most DRB4 haplotypes share common variants. Our DQA1 3’UTR sequencing detected a nucleotide insertion at the first splicing site specific for the common DRB4 haplotypes (CATGGT vs CAGGT) and a DRB4 lineage-specific sequence (CAGGT) at the second splicing acceptor site. Whether these and other sequence polymorphisms are associated with DRB4 haplotype-specific HLA-DQA1 splice variants is unknown. While all members of the DRB4 lineage shared most of the polymorphisms in these sites, the DRB3 and DRB5 groups showed heterogeneity. SNP rs1142316 allele C was shared by all haplotypes of the DRB4/DRB5/DR1 lineages while most DRB3 haplotypes (including B8/18/42/18-DR3 haplotypes) had allele A. Conclusions: It is expected that ancestral lineage specific polymorphisms within the 3’UTR of DQA1 contribute to the lineage-specific expression differences of HLA class II genes. Better characterization of this region and an efficient sequencing-based genotyping scheme should aid phylogenetic studies of the HLA complex, as well as disease association studies.
S41
67-P
LOW EXPRESSING IL-10 GENOTYPES ARE ASSOCIATED WITH CHRONIC ALLOGRAFT DAMAGE INDEX (CADI) SCORES. Faisal M. Khan,1 Serdar Yilmaz,2 Aylin Sar,2 Jagdeep Doulla,1 Iwona Galaszkiewicz,1 Noureddine Berka.1 1Tissue Typing Lab, Calgary Laboratory Services, Calgary, AB, Canada; 2Medicine, University of Calgary, Calgary, AB, Canada. Aim: Chronic Allograft Damage Index (CADI) of the 6 month protocol core needle biopsy is a strong early predictor of long-term graft functioning. ‘Genetic predisposition’ of recipients to the heritable variants in the genes encoding cytokines is a compelling risk factor for high CADI score. In this study, we examined the association of SNPs in different cytokine genes with the composite CADI score and with each of the 8 individual histological indices. Methods: A total of 115 renal transplant recipients from Southern Alberta Renal Transplant program were genotyped for 15 SNPs located in 10 cytokine/cytokine receptor genes. Genotyping was done by Luminex based cytokine assay. Results: Genotypes with low expresing alleles at two promoter ‘SNPs’ of IL-10 gene, -592AA⫹AC (p⫽0.02;OR⫽2.82) and -819TT⫹TC (p⫽0.03;OR⫽2.6) were found to be associated with high CADI score. Expression profile based linear regression analysis also showed a good correlation with high CADI score (r ⫽0.43). At allelic levels,-592A allele (p⬍0.01) and -819T allele (p⫽0.01) also found strongly associated. At individual histological index, both -592AA⫹AC (p⫽0.002;OR⫽3.7) and -819TT⫹TC (p⫽0.004;OR⫽3.6) were found to be associated with interstitial fibrosis, while former also showed association with tubular atrophy (p⬍0.01;OR⫽4.2). Conclusions: (1) Kidney allograft recipients, genetically predisposed for low producing IL-10 genotypes are associated with high CADI scores. (2) A deficient regulatory milieu may be a crucial determinant of chronic allograft damage. (3) Cytokine genotyping as a predictive test along with the CADI scores may allow better anticipation of the clinical outcomes.
68-P
COMPLETE SEQUENCING OF HLA-DQA1 3’UTR AND CORRELATIONS WITH ANCESTRAL LINEAGES. Brittany A. Morrison, M. Tevfik Dorak. Genomic Immunoepidemiology Lab, HUMIGEN LLC, The Institute for Genetic Immunology, Hamilton, NJ, USA. Aim: HLA-DQA1 has been recognized as the most ancestral HLA locus. Two alleles of the HLA-DQA1 3’UTR SNP rs1142316 correlate with the most ancestral HLA class II lineages represented by DRB3 and DRB4. Individuals homozygous for different DQA1 alleles generate multiple DQA1 mRNA isoforms through a combination of alternative splicing acceptor and polyadenylation sites in their DQA1 3’UTR. We were interested in more detailed 3’UTR sequence information in “conserved extended haplotypes.”. Methods: We sequenced the whole 3’UTR in 31 IHWG cell lines. Results: We identified new polymorphisms in splicing donor/acceptor sites and polyadenylation sites. The variants at these sites cluster with ancestral lineages, in particular, most DRB4 haplotypes share common variants. Our DQA1 3’UTR sequencing detected a nucleotide insertion at the first splicing site specific for the common DRB4 haplotypes (CATGGT vs CAGGT) and a DRB4 lineage-specific sequence (CAGGT) at the second splicing acceptor site. Whether these and other sequence polymorphisms are associated with DRB4 haplotype-specific HLA-DQA1 splice variants is unknown. While all members of the DRB4 lineage shared most of the polymorphisms in these sites, the DRB3 and DRB5 groups showed heterogeneity. SNP rs1142316 allele C was shared by all haplotypes of the DRB4/DRB5/DR1 lineages while most DRB3 haplotypes (including B8/18/42/18-DR3 haplotypes) had allele A. Conclusions: It is expected that ancestral lineage specific polymorphisms within the 3’UTR of DQA1 contribute to the lineage-specific expression differences of HLA class II genes. Better characterization of this region and an efficient sequencing-based genotyping scheme should aid phylogenetic studies of the HLA complex, as well as disease association studies.