To determine if cytokine responses to the SMG distinguish commensal from pathogenic isolates, we measured the production of IL1β, TNF, IL10, IL23, 12p70, IL17A, and IL4 from human PBMCs in response to 35 clinical isolates from either invasive infections (abscesses, bacteremia, empyema) or the CF airway cultured during periods of stability or exacerbation. Here, IL4 is linked to infection.