Increased polymorphonuclear leukocyte Fc gamma-dependent chemiluminescence in active psoriasis is not related to FcRIII (CD16) receptor expression

The role of the two main serum opsonins (IgG and C3b) in the induction of polymorphonuclear leukocyte chemiluminescence was studied in a group of psoriatic patients. Chemiluminescence was stimulated with zymosan opsonized by fresh plasma (IgG- and C3b-dependent chemiluminescence) or by complement-depleted plasma (IgG-dependent chemiluminescence). While C3b-dependent chemiluminescence was similar in patients with chronic or active forms of psoriasis, IgG-dependent chemiluminescence was significantly increased in patients with active disease. However, FcR-III expression, evaluated by means of flow cytofluorimetry, was similar in the different groups of patients studied. The discrepancy between Fc-receptor (CD16) expression and IgG-dependent chemiluminescence is, therefore, indicative of modifications that occur in psoriatic neutrophils that do not involve FcIII-receptor expression.