TLR2 and TLR4 gene expression levels and associated factors during acute attack and attack-free periods in familial Mediterranean fever.

The purpose of this clinical study was to determine if the expression of the TLR2 and/or TLR4 genes is involved in triggering the auto-inflammatory attacks in patients with familial Mediterranean fever (FMF). Thirty patients with FMF and 20 healthy control subjects were recruited. Comparisons were made in TLR2 and TLR4 gene expression levels during FMF attack episodes and attack-free periods, as well as with baseline levels in healthy control subjects. There was no significant difference in TLR2 and TLR4 gene expression between the attacks and attack-free periods in the entire group of FMF patients. However, among female patients, expression level of TLR4 gene was significantly higher during the attack than in the attack-free period (TLR2 Log 2.04 ± 0.14 vs. 2.52 ± 0.10, respectively, P = 0.02). There was not a significant difference between FMF patients and healthy subjects. The patients who had higher levels of TLR2 expression during the acute attack experienced their first attacks at an earlier age (r = -0.571; P = 0.001). The frequency of attacks, acute-phase response, MEFV mutations, and colchicine response were not associated with TLR2 and TLR4 levels. We conclude that changes in the expression of TLR2 and TLR4 genes do not appear to be involved in triggering FMF attacks. A higher level of TLR2 expression during acute attack may be related to the early onset of the disease. Further studies using specific cell populations such as neutrophils, monocytes, and dendritic cells may be useful to explore any changes in the sensitivity of toll-like receptors to their agonists, such as lipopolysaccharides, in the onset of attacks.