A validated THALAMOSS cellular biobank for β-thalassemia

The production and validation of a cellular thalassemia biobank was conducted within the multicenter European Project THALAMOSS (THALAssaemia MOdular Stratification System for personalized therapy of β-thalassemia). The cellular biobank contains hematopoietic stem cells isolated from peripheral blood, expanded and cryopreserved. This approach is based on: (a) the recruitment of β-thalassemia patients characterized for the genotype and possible fetal hemoglobin (HbF)-associated polymorphisms (XmnI rs7482144, BCL11A rs 1427407 and rs10189857, MYB rs9399137); (b) the set up of protocols to efficiently isolate, culture, freeze and thaw the hematopoietic stem cells from 25 ml aliquot of blood collected before transfusion; (c) the use of cultures for determining the effects of HbF inducers as well as the efficacy of gene therapy approaches. We demonstrated that freezing, cryopreservation and thawing steps do not affect the erythroid differentiation potential of the cells in terms of kinetics and types of hemoglobin produced. The validation of the cellular biobank was further performed by sending and culturing the cryopreserved cells from the same patients in different laboratories. Finally, we analyzed the response to different HbF inducers. The cells stored in the biobank were found to be responsive to mithramycin, hydroxyurea and resveratrol. At present, this first THALAMOSS cellular biobank is composed of 749 cryovials from 75 β-thalassemia patients. In conclusion, this research activity will allow patient stratification taking into account all the phenotypic/genotypic characteristics of the single individual associated with in vitro HbF induction under treatment with effective inducers, providing an important opportunity for the development of novel therapeutic strategies for β-thalassemia.