Definition
These are diseases linked to disorders of innate immunity. Innate immunity is immediate immunity.
It helps defend against danger signals picked up by white blood cells in the body.
These signals can be infections, temperature variations or hormonal fluctuations, stress.
Epidemiology
It is estimated that there are more than 100,000 people with autoinflammatory disease worldwide.
These diseases can affect patients from birth or occur in adulthood. They can concern patients in all countries of the world.
However, the most common of these diseases is called familial Mediterranean fever and preferentially affects patients originating from around the Mediterranean.
Genetic
Autoinflammatory diseases were initially identified as associated with mutations in genes involved in innate immunity. These are called MONOGENIC autoinflammatory diseases. These are the most frequent, in particular familial Mediterranean fever, VEXAS syndrome, cryopyrinopathies and ADA2 deficiency.
Certain diseases, where no mutated gene could be demonstrated, have been classified as autoinflammatory diseases because of their clinical and biological similarities with monogenic autoinflammatory diseases. These are called polygenic autoinflammatory diseases. These include, in adults, Still's disease, Schnitzler's syndrome and SITRAME syndrome.
Clinical
Autoinflammatory diseases affect the whole body, this is called “systemic”.
Patients most often present with flare-ups favored by triggering factors.
Triggers are perceived by white blood cells in the body as danger signals. These can be trivial situations such as heat, cold, stress, a viral infection, menstruation in women or lack of sleep.
In the event of a flare-up, general signs may appear, namely fever, fatigue and more specific attacks, in particular eruptions, abdominal and joint pain.
Other manifestations may occur depending on the disease such as red eyes, headaches, diarrhoea, lymphadenopathy and canker sores.
Diagnostic
The diagnosis is based on a bundle of clinical argument, the presence of inflammation in the blood in crisis (elevation of C-reactive protein) and the exclusion of differential diagnoses, in particular infections.
In MONOGENIC diseases, the diagnosis is confirmed by a genetic analysis (carried out on a blood test).
In POLYgenic diseases, there is a set of criteria that make it possible to make the diagnosis.
Evolution
Usually flare-ups resolve spontaneously over time but return regularly if left untreated.
If the inflammation in the blood persists for too long (several years), there may be appearance of renal insufficiency by deposition of inflammatory amyloid plaques, which constitutes a rare but serious complication of the disease.
Other complications can occur in the absence of treatment and vary according to the disease, they can lead to deafness in cryopyrinopathies and essentially joint pain or destruction in other diseases.
Treatment
The treatment aims to prevent flare-ups and to allow a good quality of life without pain and to prevent disease complications.
In familial Mediterranean fever, it relies on colchicine. In some others, we will use treatments called biotherapies which are administered by subcutaneous injections.
For some diseases, the treatment is not codified to date. An opinion in an expert reference center for the disease in question is recommended, particularly for those which are very rare.