Are follistatin-like protein 1 and follistatin-like protein 3 associated with inflammatory processes in patients with familial Mediterranean fever?

Objective: Follistatin-like protein 1 (FSTL-1) and follistatin-like protein 3 (FSTL-3) are glycoproteins whose associations with inflammatory cytokines were reported in previous studies. However, it is not yet known whether they have an effect on the pathogenesis of familial Mediterranean fever (FMF). We aimed to detect the FSTL-1 and FSTL-3 levels and to determine their relationship to the attack status and mutation types in patients with FMF.

Methods: Fifty-six FMF patients and 22 healthy controls (HCs) were included in the study. Serum FSTL-1 and FSTL-3 levels were measured with the enzyme-linked immunosorbent assay method from collected serum samples. In addition, the MEditerranean FeVer (MEFV) gene mutation types of the patients were noted.

Results: Serum FSTL-1 levels were significantly higher in FMF patients than in HCs (p=0.005). However, there was no significant difference in FSTL-1 levels between patients in the attack period (n=26) and in the attack-free period (n=30). FSTL-3 levels were similar between FMF patients and HCs or patients in the attack period and in the attack-free period. Furthermore, the MEFV mutation type and attack status had no significant effect on FSTL-1 and FSTL-3 levels (p>0.05).

Conclusion: Our results suggest that FSTL-1 may be associated with the pathogenesis of FMF, rather than FSTL-3. However, neither serum FSTL-1 nor FSTL-3 seems to be good markers to reflect inflammatory activity.