The pyrin inflammasome aggravates inflammatory cell migration in patients with familial Mediterranean fever

Experimental models in Familial Mediterranean Fever (FMF): Insights into pathophysiology and therapeutic strategies

Familial Mediterranean Fever (FMF) is a recurrent polyserositis characterized by self-limiting episodes or attacks of fever along with serosal inflammation. It mainly impacts people of the Mediterranean and Middle Eastern basin. FMF is a recessive autoinflammatory condition caused by mutation in the MEFV gene located on chromosome 16p13. MEFV mutations lead to the activation of the pyrin inflammasome resulting in an uncontrolled release of IL-1β. Various in vitro, in vivo and ex vivo experimental models have been developed to further comprehend the etiology and pathogenesis of FMF. These models have been proven to be clinically relevant to human FMF and can provide significant information about biological systems with respect to this condition. Additionally, these models have provided pertinent contributions to the development of potent therapeutic strategies against FMF. In this review, we describe the different experimental models utilized in FMF and we focus primarily on the most widely used models that have produced prominent insights into the pathophysiology of the disease.

Cellular models in autoinflammatory disease research

Systemic autoinflammatory diseases are a heterogeneous group of rare genetic disorders caused by dysregulation of the innate immune system. Understanding the complex mechanisms underlying these conditions is critical for developing effective treatments. Cellular models are essential for identifying new conditions and studying their pathogenesis. Traditionally, these studies have used primary cells and cell lines of disease-relevant cell types, although newer induced pluripotent stem cell (iPSC)-based models might have unique advantages. In this review, we discuss the three cellular models used in autoinflammatory disease research, their strengths and weaknesses, and their applications to inform future research in the field.

Protracted febrile myalgia as a first and challenging manifestation of familial Mediterranean fever

OBJECTIVES

Familial Mediterranean fever (FMF) is an auto-inflammatory disease that causes recurrent episodes of fever, abdominal pain, chest pain, and arthritis. Although FMF is well known, protracted febrile myalgia syndrome (PFMS) is a clinical condition that is rare and difficult to diagnose than other symptoms of FMF. PFMS causes fever, myalgia, and acute phase reactant elevation that lasts 2-4 weeks if corticosteroid treatment is not given. In some cases, fever may not be seen. The purpose of this report is to share our experience with PFMS patients in our clinic.

METHODS

This is an observational, retrospective, single-centre study. We evaluated patients who had been diagnosed with PFMS at our paediatric rheumatology clinic.

RESULTS

Protracted febrile myalgia syndrome was observed in 14 patients. Nine of the patients were female. The median age at the time of diagnosis of PFMS was 10 years. Only three patients had previously been diagnosed with FMF. Most of our patients were patients who had no previous complaint of FMF. PFMS attack was seen as the first clinical manifestation of FMF in 11 patients. Two patients who did not respond to steroid treatment improved with anakinra treatment.

CONCLUSIONS

PFMS is a rare condition of FMF disease. It may be the first clinical manifestation of FMF disease. Fever may not be seen in all patients. Clinicians should be aware of this situation.