RT-PCR analysis of the expression of IL-15 message and flow cytometry analysis of membrane and cytoplasmic expression of IL-15 by pulmonary macrophages recovered from three representative patients with HIV infection and high-intensity T-cell alveolitis and a control subject who showed a normal cell recovery (bottom series of panels). Highly purified alveolar macrophages retrieved from the patients showed a strong IL-15 message. Furthermore, they bore membrane – and cytoplasmic–IL-15, whereas alveolar macrophages retrieved from the normal individual did not.