IL10-592 CC Genotype In the Donor Is Associated with a Significant Decrease of Relapse Rate and a Significant Increase of Event-Free Survival and Overall Survival After Allogeneic Hematopoietic Stem Cell Transplantation In Children with Hematological Malignancies

Abstract 4459

IL10 is a pivotal immunomodulatory cytokine and is usually regarded as a suppressor of the immune responses. However, IL10 has been shown to have some immunostimulatory effects. The IL10-592 CC genotype is associated wit higher production of IL10. Because IL10 may promote the development of alloimmunity we hypothesized that the IL10-592 CC genotype in the donor reduces the risk of relapse after hematopoietic stem cell transplantation (HSCT). A cohort of 211 children (median age, 12 years) with acute lymphoblastic leukemia (n=100), acute myeloid leukemia (n=62), myelodysplastic syndrome (n=30) or chronic myeloid leukemia (n=19) who underwent allogeneic bone marrow (n=153) or peripheral blood stem cell transplantation (n=58; T-cell depleted: n=26) in a single center and/or their respective donors was genotyped of IL10 gene for rs1800872 using TaqMan real-time polymerase chain reaction. The donor was HLA-matched unrelated in 48% of transplants and HLA-identical related in 42% of transplants. Conditioning regimen was myeloablative in all cases. Two forms of post-transplant immunosuppression predominated, cyclosporine A and methotrexate in 69% of transplants and cyclosporine A alone in 17% of transplants. Cell samples from the donor were available in 174 cases and from the patient in 197 cases. The IL10-592 CC genotype was present in 82 of the 174 donors (47.1%) and in 104 of the 197 patients (52.8%). Interestingly, we found a significantly reduced incidence of relapse in patients who were transplanted from a donor with the IL10-592 CC genotype (15.9% versus 30.4%; p=0.016). In addition, we observed a significant increase of event-free survival (52.4% versus 33.7%; p=0.019) and a significant increase of overall survival (54.9% versus 37.0%; p=0.040) if the IL10-592 CC genotype was present in the donor. The occurrence of the IL10-592 CC genotype, in either donors or recipients, had no significant impact on treatment related mortality, acute and chronic graft-versus host disease. In conclusion, IL10-592 CC genotype in the donor is associated with a significant decrease of relapse rate and a significant increase of event-free survival and overall survival after HSCT in children with hematological malignancies. This is the first study to describe an association of IL10 gene polymorphism with relapse rate after HSCT. Selecting a donor with the IL10-592 CC genotype could be a useful therapeutic strategy for improving the final outcome after allogeneic HSCT.