THE INTERACTION OF MONOCLINIC CALCIUM PYROPHOSPHATE DIHYDRATE CRYSTALS WITH NEUTROPHILS

Monoclinic calcium pyrophosphate dihydrate (m-CPPD) crystals were synt hesized and characterized using physical methods, IgG binding to m-CPP D crystals was quantitated, and the effect of IgG or plasma opsonizati on on m-CPPD-induced neutrophil activation was determined. Adsorption of Ige to crystals was measured using fluorescent-labelled FITC-IgG. N eutrophil activation by uncoated m-CPPD and crystals precoated with Ig G or plasma was measured using luminol-enhanced chemiluminescence, sup eroxide anion generation, and myeloperoxidase release. m-CPPD bound sm all (compared to triclinic CPPD) but significant amounts of IgG and in duced a strong activation of neutrophils at low concentrations of crys tals. The rate and extent of chemiluminescence, superoxide anion produ ction, and degranulation was not affected by precoating m-CPPD crystal s with IgG during the early phase of neutrophil responses, but was inh ibited by the precoating of crystals with plasma.