Patient characteristics were similar between the four cohorts, including gender, age, residence, educational level, HIV transmission route, cART therapy, years of HIV infection before lymphoma, ECOG-PS, the presence of B symptoms, elevated serum LDH, elevated serum β2-MG, Ann Arbor stage, IPI score, extra-nodal involvement, bone marrow involvement, CNS involvement, CD4 cell count, and chemotherapy regimen. Here, CD4 is linked to lymphoma.