Production of influenza-stimulated tumor necrosis factor-alpha by monocytes following acute influenza infection in humans

Tumor necrosis factor-alpha (TNF-alpha) is often measured in the serum or p lasma of patients with severe infections, and marked elevation correlates w ith poor outcome. The relationship of TNF-alpha to protection from disease is frequently not observed because prospective studies of infectious agents are difficult to perform. We took advantage of a human antiviral influenza challenge study to correlate TNF-alpha production with seroconversion and symptom development. TNF-alpha production was measured by ELISA in the plas ma compartment or was measured by intracellular production at the single ce ll level in the monocyte gated population. Monocyte TNF-alpha was associate d with asymptomatic seroconversion, whereas there was no change in the plas ma at the times measured. Measurement of TNF-alpha at the single cell level by flow cytometry may allow for better differentiation of the protective r ole of this cytokine in future studies.