Moreover, the number of CD4-positive lymphocytes has been reported to decrease significantly after chemotherapy in patients with HBV-associated DLBCL, and the CD4:CD8 ratio decreased for a longer time in the aforementioned population than in HBV-free individuals, elucidating the reason behind the poor prognosis of patients with HBV-associated: The host immune system weakened the tumor surveillance effect, leading to rapid disease recurrence and poor prognosis (41). This evidence concerns the gene CD4 and diffuse large B-cell lymphoma.