The results obtained (i) confirmed the ability of tisagenlecleucel to control the disease at least for a limited period of time; (ii) showed that many patients who subsequently relapsed could undergo further treatment; (iii) showed that the in vivo release of cytokines, particularly IL-6, was associated with a clinical CRS; (iv) documented a significant increase in CD3+, CD4+, CD8+, and NK cells over time; (v) indicated that immune modulation was associated with a decrease in the percent of Treg cells and (vi) an increased capacity of T lymphocytes to produce IFNγ and TNFα. Here, CD4 is linked to congenital rubella syndrome.