Diminished levels of S1P1 and KLF2 RNAs in HIV-1 + LNs. (A) S1P1 and (B) KLF2 gene expression in LN tissues was assessed by real-time PCR and normalized to levels of 18S rRNA. (C) S1P1 and (D) KLF2 gene expression in purified T cells was assessed by real-time PCR and normalized to levels of 18S rRNA.