Macrophages from CGD patients activate caspase-1 and secrete mature IL-1β. (A-B) Caspase-1 activation in monocyte-derived macrophages determined by a fluorescent inhibitor of active caspase-1 (FLICA). (A) Lipopolysaccharide (LPS)–primed (−) macrophages from a chronic granulomatous disease (CGD) patient (p22) and a healthy control (C1) stimulated for 1 hour with adenosine triphosphate (ATP) or for 6 hours with silica crystals (SiO₂) or monosodium urea (MSU) crystals. Numbers above bracketed lines indicate percentage of cells with active caspase-1. (B) Active caspase-1 in macrophages from 3 CGD patients with the indicated mutations and 3 healthy controls (C1-C3) quantified by caspase-1 FLICA. (C-E) Macrophages from the indicated CGD patients and healthy donors stimulated with LPS plus ATP, nigericin (NI), SiO₂, or MSU. The production of mature interleukin-1β (IL-1β) at the indicated time points was determined by enzyme-linked immunosorbent assay. Data are representative of 6 experiments with cells from at least 5 different CGD patients (error bars indicate SEM of triplicate wells).