In combination with the baseline CD4+ cell count, the TTV DNA plasma level enables clinicians to predict the course of immune reconstitution, which could help to provide guidance for individualized treatment decisions as for example planning of indication and duration of prophylactic anti-infective treatments to prevent opportunistic infections, to avoid unnecessary drug toxicity or before initiating glucocorticoids in tuberculosis patients with high risk of IRIS [48]. The gene discussed is CD4; the disease is Opportunistic infection.