Background: Posttransplant thrombocytopenia is prevalent after renal transplantation, which is associated with increased risk of bleeding and other complications. The CXC motif chemokine 12 (CXCL12) and Platelet Factor 4 (PF4) genes are known to be involved in the production or destruction of platelets. This research aims to investigate prevalence of posttransplant thrombocytopenia and its association with genetic polymorphisms of CXCL12 and PF4 genes.

Methods: This is a retrospective study, which includes chart review of 400 kidney transplant patients at the St. Vincent Medical Center, CA between January 2008 – December 2012. Among these, patients whose genomic DNAs not available were excluded (95 patients). Our posttransplat thrombocytopenia is defined as 30% reduction of platelet counts from the baseline at the first week after kidney transplantation. The remaining 305 patients are divided into two group; The study group is those who met our definition of posttransplant thrombocytopenia and the control group, who did not develop thrombocytopenia. A chi square test was used for comparison and the odd ratios were calculated. It is hypothesized that genomic polymorphisms of CXCL12 and PF4 are associated with incidence of posttransplant thrombocytopenia.

Result:A total of 65 patients developed posttransplant thrombocytopenia (21%). Alleles of rs1801157, rs2297630 of CXCL12 and alleles of rs1435520, rs1429637and rs442155 for PF4 were included for the analysis. After conducting polymerase chain reaction (PCR) test on patient's genomic DNA, we determined only allele rs2297630 of CXCL12 showed a statistically significant difference between the alleles (A to G) (Odds ratio=0.513, C.I.=[0.279-0.944], c²= 4.70, p=0.03010 ) and any of the remaining genes are not significantly different between the groups. The odds ratio indicated that the presence of allele G in gene rs2297630 decrease the risk of posttransplant thrombocytopenia by 50% compare to presence of allele A.

Conclusion:Our study suggests that genetic polymorphisms of CXCL12genes may have an association with reduced risk of posttransplant thrombocytopenia. Further study is needed to confirm this association with a large sample size.

CITATION INFORMATION: Min D., Chang Y., Shah T. Genetic Risk Factors of Post-Transplant Thrombocytopenia in Kidney Allograft Recipients Am J Transplant. 2017;17 (suppl 3).

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