To test whether JAK2-STAT5 signaling is required for GM-CSF-enhanced cytokine production, we treated THP-1 human monocytes with the JAK2 inhibitor NVP-BSK805 or STAT5 inhibitor SH-4-54 prior to stimulation with GM-CSF and Legionella infection. This evidence concerns the gene JAK2 and legionellosis.