Adenoviral load in relation to T-cell numbers. A 2-year-old girl was treated with unrelated cord blood HSCT for Hurler syndrome (nonmalignant, MPS1). She developed an AdV primo infection or reactivation, which was detectable by AdV qPCR (100 cp/mL) at day 19. Within a period of 4 days the viral load increases by 2 log, and cidofovir is started. There are no signs of disease. Only as CD3 numbers (gray line) are increasing, adenoviral load (black line) goes down. The downward pointing arrow indicates the timing of intensification of therapy with immunosuppressants when the period after HSCT is complicated by steroid refractory autoimmune cytopenia; she receives mycophenolate mofetil 45 mg/kg/d, prednisone 2 mg/kg/d, anti-CD20 therapy, and fludarabine infusions from day 314. When symptoms stabilize, immunosuppressants are tapered over time and can be stopped at day 455 after HSCT. Tapering of immunosuppressants is associated with CD3⁺ T-cell recovery and clearance of advenoviremia.