Prevention of cytokine‐induced changes in leukocyte adhesion receptors by nonsteroidal antiinflammatory drugs from the oxicam family

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Abstract
Objective. To explore the effect of the nonsteroidal antiinflammatory drugs (NSAIDs) piroxicam and meloxicam on quantitative and qualitative changes in leukocyte adhesion receptors induced by cytokines and other activation stimuli. Methods. The expression of CD11b and L‐selectin during neutrophil activation with tumor necrosis factor α (TNFα), granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), FMLP, phorbol myristate acetate (PMA), and calcium ionophore A23187 was assessed by flow cytometry. Enzyme‐linked immunosorbent assays were used to quantitate soluble L‐selectin shed after neutrophil stimulation. Enzyme release was measured to determine neutrophil degranulation by proinflammatory stimuli. Changes in affinity state of β1 and β2 integrins after neutrophil and T lymphocyte stimulation were assessed, by flow cytometry, using the monoclonal antibodies (MAb) HUTS‐21 (anti‐β1) and CBRM1/5 (anti‐CD11b), which recognize activation‐dependent epitopes on these two integrins. Results. Pretreatment of neutrophils with either NSAID prevented the changes in L‐selectin and CD11b expression induced by TNFα, GM‐CSF, and FMLP, but not those induced by PMA or A23187. Furthermore, piroxicam significantly decreased the amount of L‐selectin shed by cytokine‐treated neutrophils, whereas it did not exert this effect on PMA‐ or A23187‐treated neutrophils. Piroxicam also decreased the release of gelatinase and lysozyme induced by TNFα, but not by PMA. Interestingly, piroxicam prevented the conformational changes that β2 integrins underwent upon activation of neutrophils: the appearance of the activation epitope of CD11b, detected by the CBRM1/5 MAb, was blocked by piroxicam in TNFα‐treated neutrophils. Moreover, in chemokine‐treated T lymphocytes, the expression of activation epitopes on β1 integrins was also diminished by piroxicam. In contrast, this NSAID did not affect the β1 integrin conformational changes induced by PMA or Mn++. Conclusion. Our results indicate that members of the oxicam family are able to interfere with events of neutrophil function, such as their degranulation and cytokine‐mediated activation changes in adhesion molecules, both in neutrophils and in lymphocytes. Such effects may significantly contribute to the antiinflammatory activity of these drugs.