Multi-omics research applied to Human ADA2 deficiency and beyond

ongoing

Human adenosine type 2 (ADA2) deficiency is a rare but devastating condition resulting in a complex phenotype of vasculitis (ranging from cutaneous to intracerebral vasculitis with lacunar infarcts), immunodeficiency (recurrent bacterial or viral infections), bone marrow anomalies (cytopenia, aplasia), cancer (lymphoma, leukemia). Mortality is 10%, often in childhood. The mainstay of treatment consists of anti-TNF blockade for vasculitis. Cytopenia and immunodeficiency respond poorly. Hematopoietic stem cell transplantation is curative in most cases. Although the condition was described in 2014, its pathophysiology is unsolved. From previous work in my laboratory, I have gained insight that ADA2 is likely to play a significant role in antiviral host defense and endothelial function. I thus hypothesize that ADA2 deficiency is an underdiagnosed condition and that complete or partial ADA2 deficiency plays a role in several other common medical conditions. With this research proposal, I aim (1) to unravel the pathophysiology of ADA2 deficiency, to (2) study the significance of ADA2 deficiency in phenocopies of the disease (3) to study the function of ADA2 in vitro (4) to develop new treatment strategies for ADA2 deficiency and its phenocopies. To achieve these aims I will study the prevalence of ADA2 deficiency in cohorts of patients presenting with one or more of the main disease characteristics (e.g. juvenile stroke, aplasia, childhood lymphoma...) by genetic and functional approaches. The genotype, immunophenotype and clinical characteristics of these patients will be studied using the newest technologies. In cell lines and tissue samples of ADA2 deficient patients, we will study the function of ADA2. Finally, we will screen known and novel drugs for their potential use in ADA2 deficiency and phenocopies, even beyond, in cardiovascular disease, cancer, anti-viral host defense.