Enhanced neutrophil chemiluminescence in familial Mediterranean fever

Familial Mediterranean Fever is a disorder of unknown cause characterized by recurrent, self-limited paroxysms of serosal inflammation. Although the neutrophil is the predominant cell involved, no cellular abnormalities are known. Chemiluminescence was studied in neutrophils from 20 asymptomatic patients with this disease and 21 healthy controls to evaluate the oxidative response to formyl-methionyl-leucyl-phenylalanine (f-met-leu-phe). In a subset of patients with familial Mediterranean fever, neutrophils but not monocytes were shown to have significantly enhanced chemiluminescence compared to controls. The enhanced responsiveness of neutrophils to f-met-leu-phe in this disease was found to occur at a postreceptor level. Receptor binding assays demonstrated no differences in binding affinity and receptor number between patients and controls. In addition, a similar enhancement in chemiluminescence was observed with an alternative stimulus (zymosan). In contrast to chemiluminescence, chemotaxis induced by f-met-leu-phe was not enhanced in patients with familial Mediterranean fever. The enhanced neutrophil chemiluminescence may identify a subclinical inflammatory state in attack-free patients with familial Mediterranean fever, as enhanced chemiluminescence is also observed in chronic inflammatory diseases with active inflammation.