Altered Ca2" signalling inhumanneutrophils from inflammatory sites

Objectives-To determinewhetherthe intracellular storereleaseof Ca2"in neutrophils frompatients withrheumatoidarthritis, otherjointdisease and active legulceration wasdifferent from normalneutrophils. Methods-Therelease intothecytosol of Ca2" fromstores within individual neutrophilswasdetermined usingratiometric imaging offura2. Thesizeoftheelevated Ca2"'cloud' anditsconcentration were quantified in neutrophils from the circulation ofpatients withrheumatoid arthritis, otherjointdiseases, and leg ulcers andfromthejoints ofthosewith joint disease. Results-Inneutrophils isolated from boththesynovial fluidofpatients with rheumatoid arthritis andotherjoint conditions, andalsoarising fromlegulcers, theamountofthecell cytosol occupied by elevated Ca21wassignificantly increased compared withneutrophils fromhealthy subjects; forneutrophils from rheumatoid,non-rheumatoid joints andleg ulcers pvalues were0-0006, <0-0001, 0-016 respectively (Student's ttest). Therewas alsoasignificant increase inCa2'release from circulating neutrophils from patientswith rheumatoidarthritis (p=0.09), butnotincirculating neutrophils frompatients withlegulcers ornonrheumatoid joint conditions. Conclusions-It isproposedthatthe increased release offreeCa2"intothe cytosol ofneutrophil atinflammatory sites results inincreased oxidase activation.