Granzyme B (attack 4029.2±851.3 pg/mL vs attack-free 3002.1±1958.2 pg/mL; p=0.145) and Perforin (attack 9684.8±16180.4 pg/mL vs attack-free 5300.8±4603.5 pg/mL; p=0.203) levels were also increased during attack period of FMF patients however these differences were not statistically significant. This evidence concerns the gene PRF1 and familial Mediterranean fever.