The importance of serial measurements of cytokine levels for the evaluation of their role in pathogenesis in familial Mediterraean fever.

Familial Mediterranean fever (FMF) is an autosomal recessive disorder characterized by recurrent fever of unknown origin, renal amyloidosis, peritonitis, pleuritis and/or synovitis. There have been many studies to elucidate the etiopathogenesis of FMF. IL-6 is a cytokine that can induce the formation of serum amyloid A and C-reactive protein, both of which are important in development of amyloidosis. IL-6 was determined to be strongly associated in the etiopathogenesis of periodic fever in Chinese-pei dogs. The dogs with this syndrome experience periodic fever, arthritis, renal amyloidosis, a clinical picture very alike of human FMF. Here, we aimed to study mainly whether IL-6 had a similar etiopathogenetic role in human FMF as in Chinese-pei dogs syndrome. The median IL-6 blood levels were found to be higher in patients with acute (n=8) FMF attack (1.85 U/ml) compared to those (n=33) with asymptomatic ones (1.0 U/ml) (p=0.16). There are mainly two results: first; the study should be designed with a larger sample size of patients with acute attack in order to alleviate underestimation of significance, second; sampling time may give various results because of dynamic changes of cytokine levels during acute attack period.