RT-PCR analysis and flow cytometry profile of the expression of IL-15R, IL-2Rβ, and the γ_c by AM. The figure shows a representative healthy subject (subject #4) but a consistent pattern of expression was observed in six consecutively examined normal subjects. 94% of BAL cells of subject #4 were alveolar macrophages and 7% lymphocytes, as determined by morphological evaluation; the CD4/CD8 ratio was 1.9. AM were enriched as reported in the Materials and Methods section. AM bore high levels of IL-15R and γ_c whereas a faint expression of IL-2Rβ is detectable.