The priming action of tumour necrosis factor‐alpha (TNF‐α) and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) on neutrophils activated by inflammatory microcrystals
We studied the effects of TNF‐α or GM‐CSF on the production of reactive oxygen species (as measured by chemiluminescence) and degranulation responses of neutrophils to opsonized inflammatory microcrystals. TNF‐α in the 10–2000 pm or GM‐CSF in the 2–200 pm concentration range caused the concentration‐dependent amplification of neutrophil chemiluminescence responses to both calcium pyrophosphate dihydrate (CPPD) and monosodium urate monohydrate (MSUM) crystals. Degranulation responses, as measured by the extracellular release of the granule enzymes myeloperoxidase or lysozyme, were amplified by ≈ 50–100% for both MSUM or CPPD crystal‐induced neutrophil activation when cells were pretreated with TNF‐α at 2000 pm or GM‐CSF at 75 pm.