Reference to the success of regulated gene therapy medicine, such as StrimvelisTM for adenosine deaminase (ADA)-deficient severe combined immunodeficiency (SCID) and Zynteglo for beta thalassemia, would also assist considerations accounting for potential IDLV application in clinical studies (Aiuti, Roncarolo & Naldini, 2017; Schuessler-Lenz, Enzmann & Vamvakas, 2020). This evidence concerns the gene ADA and severe combined immunodeficiency.