Periodic fever syndromes are a set of disorders characterized by recurrent episodes of

systemic Systemic fundamental to a predominant social, economic, or political practice. This refers to: In medicine In medicine, ''systemic'' means affecting the whole body, or at least multiple organ systems. It is in contrast with ''topical'' or ''loc ...

and organ-specific

inflammation Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molec ...

. Unlike autoimmune disorders such as systemic lupus erythematosus, in which the disease is caused by abnormalities of the

adaptive immune system The adaptive immune system, also known as the acquired immune system, is a subsystem of the immune system that is composed of specialized, systemic cells and processes that eliminate pathogens or prevent their growth. The acquired immune system ...

, people with autoinflammatory diseases do not produce

autoantibodies An autoantibody is an antibody (a type of protein) produced by the immune system that is directed against one or more of the individual's own proteins. Many autoimmune diseases (notably lupus erythematosus) are associated with such antibodies. ...

or antigen-specific T or B cells. Instead, the autoinflammatory diseases are characterized by errors in the

innate immune system The innate, or nonspecific, immune system is one of the two main immunity strategies (the other being the adaptive immune system) in vertebrates. The innate immune system is an older evolutionary defense strategy, relatively speaking, and is the ...

. The syndromes are diverse, but tend to cause episodes of fever, joint pains, skin rashes,

abdominal pain Abdominal pain, also known as a stomach ache, is a symptom associated with both non-serious and serious medical issues. Common causes of pain in the abdomen include gastroenteritis and irritable bowel syndrome. About 15% of people have a m ...

s and may lead to chronic complications such as

amyloidosis Amyloidosis is a group of diseases in which abnormal proteins, known as amyloid fibrils, build up in tissue. There are several non-specific and vague signs and symptoms associated with amyloidosis. These include fatigue, peripheral edema, weig ...

. Most autoinflammatory diseases are genetic and present during childhood. The most common genetic autoinflammatory syndrome is

familial Mediterranean fever Familial Mediterranean fever (FMF) is a hereditary inflammatory disorder. FMF is an autoinflammatory disease caused by mutations in Mediterranean fever gene, which encodes a 781–amino acid protein called pyrin. While all ethnic groups are sus ...

, which causes short episodes of fever, abdominal pain, serositis, lasting less than 72 hours. It is caused by mutations in the MEFV gene, which codes for the protein

pyrin ''MEFV'' (Mediterranean fever) is a human gene that provides instructions for making a protein called pyrin (also known as marenostrin). Pyrin is produced in certain white blood cells (neutrophils, eosinophils and monocytes) that play a role in i ...

. Pyrin is a protein normally present in the inflammasome. The mutated pyrin protein is thought to cause inappropriate activation of the inflammasome, leading to release of the pro-inflammatory cytokine

IL-1β Interleukin-1 beta (IL-1β) also known as leukocytic pyrogen, leukocytic endogenous mediator, mononuclear cell factor, lymphocyte activating factor and other names, is a cytokine protein that in humans is encoded by the ''IL1B'' gene."Catabolin ...

. Most other autoinflammatory diseases also cause disease by inappropriate release of IL-1β. Thus, IL-1β has become a common therapeutic target, and medications such as anakinra, rilonacept, and

canakinumab Canakinumab ( INN), sold under the brand name Ilaris, is a medication for the treatment of systemic juvenile idiopathic arthritis (SJIA) and active Still's disease, including adult-onset Still's disease (AOSD). It is a human monoclonal antibod ...

have revolutionized the treatment of autoinflammatory diseases. However, there are some autoinflammatory diseases that are not known to have a clear genetic cause. This includes PFAPA, which is the most common autoinflammatory disease seen in children, characterized by episodes of fever, aphthous stomatitis,

pharyngitis Pharyngitis is inflammation of the back of the throat, known as the pharynx. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, difficulty swallowing, swollen lymph nodes, and a hoa ...

, and cervical adenitis. Other autoinflammatory diseases that do not have clear genetic causes include

adult-onset Still's disease Adult-onset Still's disease (AOSD) is a form of Still's disease, a rare systemic autoinflammatory disease characterized by the classic triad of fevers, joint pain, and a distinctive salmon-colored bumpy rash. The disease is considered a diag ...

systemic-onset juvenile idiopathic arthritis Systemic-onset juvenile idiopathic arthritis (or the juvenile onset form of Still's disease) is a type of juvenile idiopathic arthritis (JIA) with extra-articular manifestations like fever and rash apart from arthritis. It was originally called sy ...

, Schnitzler syndrome, and chronic recurrent multifocal osteomyelitis. It is likely that these diseases are multifactorial, with genes that make people susceptible to these diseases, but they require an additional environmental factor to trigger the disease.

Individual periodic fever syndromes

References

External links

{{Medical resources , DiseasesDB = 9836 , ICD10 = {{ICD10, E, 85, 0, e, 85 , ICD9 = {{ICD9, 277.31 , ICDO = , OMIM = , MedlinePlus = , eMedicineSubj = article , eMedicineTopic = 952254 , MeshID = D056660
Understanding Autoinflammatory Diseases
nbsp;- US National Institute of Arthritis and Musculoskeletal and Skin Diseases Inflammations Autoinflammatory syndromes

Individual periodic fever syndromes

See also

Further reading

References

External links