In LN tissue sections, 84% of CD4+ T cells in uninfected LN samples from 2 participants without HIV infection and approximately 77% of CD4+ T cells in LN sections from 5 Fiebig I participants were pTEFb+ (double positive for cyclin T1 and CDK9) (Table 6 and Figure 3I). Here, CDK9 is linked to HIV infectious disease.