Decreased interleukin 1 activity released from circulating monocytes of patients with familial Mediterranean fever during in vitro stimulation by lipopolysaccharide.

Familial Mediterranean fever (FMF) is an inherited disorder of unknown etiology characterized by recurrent episodes of serous membrane inflammation. Interleukin 1 (IL-1) is a mediator of inflammatory processes. We hypothesized that IL-1 may play a role in acute attacks of FMF. Thus we tested IL-1 production by monocytes derived from patients with FMF. Nine patients were tested during acute attacks and 9 were asymptomatic when tested. Monocytes derived from peripheral blood of patients and controls were stimulated with lipopolysaccharide (LPS) and IL-1 activity in the supernatant was tested using a T helper cell line (D10-4G.1). IL-1 secretion during acute attacks was decreased whereas IL-1 production in asymptomatic patients was comparable to healthy controls. Followup of symptomatic patients during the recovery period revealed normalization of IL-1 secretion. Addition of indomethacin (prostaglandin E2 inhibitor) to LPS stimulated monocytes did not change IL-1 activity in patients or healthy controls. We conclude that in vitro IL-1 activity in patients with FMF is associated with the intensity of the inflammatory process.