Autoinflammatory diseases are a group of rare disorders caused by malfunctioning of the innate immune system.

Clinically, the disorders are usually characterised by:

• Recurrent episodes of fever and extensive inflammation, alternated by symptom-free periods. The attacks of fever are accompanied by general ill health and varying combinations of local inflammatory symptoms, including those of the skin, mucosa, serosa (peritoneum, pulmonary membrane), bone, and joints. There is often a distinctive onset and course, which varies depending on the type of disease.
• In some of the clinical pictures, patients suffer especially from hives and fever, while in others patients suffer from aphthous ulcers, a sore throat and enlarged lymph nodes with fever.
• There are also autoinflammatory syndromes in which the inflammation is more chronically present, such as in the case of non-infectious inflammation of the bones or certain inflammations of the intestines, or skin disorders.

Additional blood tests show elevated inflammation levels (especially CRP) and usually high numbers of white blood cells (especially granulocytes). This is common with infections, but in patients with autoinflammatory disease, infections are not found. Sometimes a lot of tests are needed to rule out other causes of inflammation/fever before the diagnosis autoinflammatory disease can be given.

A genetic abnormality is often responsible for the malfunctioning of the innate immune system. The genetic abnormalities in autoinflammatory diseases form proteins that play a role in the innate immune system. However, there is no direct link between the genetic abnormality and how it is expressed. Many autoinflammatory disorders are seen within families.

Thanks to improvements in genetic diagnostics and increased knowledge of how the innate immune system works, many different autoinflammatory diseases have been identified over the past decade.

Treatment varies by disease but generally consists of suppressing the innate immune system. (see medication overview)

Autoinflammatory disorders can develop during childhood and in adulthood. People usually suffer their whole life from episodes of extensive inflammation, but there is (considerable) variation per disorder and per individual in the frequency and severity of the episodes. Complications, medication side effects, and permanent (organ) damage may occur.

The severity and frequency may vary by life stage. A feared long-term complication of most autoinflammatory diseases is systemic amyloidosis. This is caused by the protein amyloid. The production of this protein increases during inflammation. If a lot of these proteins are present in the blood over a long period of time, they can start to build up in the organs, especially in the kidneys. Timely treatment, including with biologics, can improve the prognosis and reduce the risk of developing amyloidosis.