Continuity of cytokine activation in patients with familial Mediterranean fever

Familial Mediterranean fever (FMF) is a recessively inherited inflammatory disorder, characterized by recurrent attacks of fever and polyserositis. It has been considered that miscellaneous cytokines take part in the pathogenesis of the disease. The aim of this study was to investigate serum levels of soluble interleukin-2 receptor (sIL-2R), interleukin-6 (IL-6), and interleukin-10 (IL-10) in patients with FMF. The study included 42 patients with FMF (3 females, 39 males, mean age: 24.43 years) and 20 healthy volunteers as the control group (18 males, 2 females, mean age: 23.2 years). The patients were chosen according to Eliakim criteria. After recording their history and performing an examination, leukocyte counts, erythrocyte sedimentation rates (ESR), C-reactive protein (CRP), fibrinogen, sIL-2R, IL-6, and IL-10 levels were measured before and during attacks. A significant increase was found in leukocyte (p<0.001), ESR (p<0.001), CRP (p<0.001), and fibrinogen (p<0.001) levels of the patient group in the attack period compared to those in the quiescent state. sIL-2R (p=0.019) and IL-6 (p<0.001) levels showed significant increases during attacks compared to the levels before an attack. There was no significant difference between IL-10 levels. The levels of the three cytokines were significantly high both before and during the attacks compared to the control group. As a result, the elevation of sIL-2R and IL-6 levels both before and during the attacks compared to control group suggests the existence of continuous cytokine activation in the patients. No significant increase in the IL-10 levels in spite of the significant rise of sIL-2R and IL-6 during attacks supports the notion of inflammation and also reveals that compensation by anti-inflammatory IL-10 does not seem to occur.