IL-6 and LPS induce MCP-1 secretion in healthy and HIV-seropositive individuals. PBMCs from 6 healthy controls and 6 HIV-seropositive individuals were cultivated with medium alone (Medium), IL-6 (0.24 nmol/L), or LPS (1 μg/mL). After 72 hours of culture, supernatants were harvested and frozen at −80°C until tested for MCP-1 content. Each symbol corresponds to a culture established from a single individual. The lines indicate the mean MCP-1 concentrations: 0.7 (medium), 29 (IL-6), and 28 (LPS) ng/mL for healthy controls and 0.5 (medium), 27.3 (IL-6), and 14.9 (LPS) ng/mL for HIV-seropositive individuals, respectively. No statistical differences in terms of MCP-1 production after stimulation with LPS were observed between cultures established from HIV-negative and HIV-seropositive individuals (P = .15, nonparametric Rank Sums test). A total of 27 ng/mL of MCP-1 was produced from 1 patient (○) after 8 days of stimulation with LPS.