s34_ab6

Levels of interleukin-6 (IL-6) and its soluble receptor (sIL-6R) in familial Mediterranean fever (FMF) patients and their first degree relatives

S. Öktem¹, T.U. Yavuzsen², B. Sengül², H. Akhunlar³, S. Akar², M. Tunca²

Department of Rheumatology¹, Ege University School of Medicine; and Departments of Internal Medicine² and Biochemistry³, Dokuz Eylül University School of Medicine, Izmir, Turkey.

ABSTRACT
Objective
Familial Mediterranean Fever (FMF) is a hereditary disease characterized by recurrent inflammatory attacks. A subclinical inflammation may persist in periods between the attacks and heterozygotes may have higher than normal levels of acute phase proteins. We investigated the levels of interleukin-6 (IL-6) and its soluble receptor (sIL-6R) in FMF patients and their obligatory carrier relatives.

Methods
Serum levels of IL-6 and sIL-6R were measured during acute attacks (n = 18) and in attack-free FMF patients (n = 26), obligatory carriers of FMF (n = 17) and normal controls (n = 11).

Results
The median levels of IL-6 were significantly higher (45.71 pg/ mL, p = 0.001) during acute attacks of FMF only, and were normal (0.01 pg/ mL) in the other groups studied. There was no statistically significant difference in the median sIL-6R values between any of the groups (p = 0.22).

Conclusion
IL-6 was extremely elevated during FMF attacks but could not detect hypothetical "subclinical" inflammation during attack-free intervals or in the heterozygote relatives of patients. Serum levels of sIL-6R were comparable in all four groups.

Key words
Familial Mediterranean fever (FMF), IL-6, sIL-6R, FMF carriers.

Please address correspondence to: Selda Öktem, MD, Ege University School of Medicine, Department of Rheumatology, Bornova 35100, Izmir, Turkey.
E-mail: seldaoktem@yahoo.com