RT-PCR analysis of the expression of the messages for the IL-15Rα chain and control β-actin in lung T cells and alveolar macrophages (AMs). Lane 1, molecular weight (MW) marker (molecular weight VI-digested); lane 2, positive control (C+) (PBMCs stimulated for 12 hours with phytohemagglutinin, 5 μg/mL); lane 3, the negative control (C−) (sample without cDNA); lanes 4 to 9, alveolar macrophages and lung T cells isolated from three representative patients with HIV infection (cases no. 1, 4, and 9 in Table 1). A faint expression of IL-15Rα chain mRNA was detectable by RT-PCR in purified lung T cells while alveolar macrophages bore higher levels of IL-15Rα chain mRNA at the transcript level.