Le syndrome de Schnitzler

[Interleukin-1, inflammasome and autoinflammatory diseases]

Interleukin-1 is a major cytokine of innate immunity and inflammation. It exerts various systemic effects during the inflammatory response, such as fever induction, thrombopoiesis and granulopoiesis, or leukocyte recruitment. Its involvement has been demonstrated in many inflammatory-mediated diseases, such as diabetes or gout. Moreover, interleukin-1 plays a pivotal role in some autoinflammatory diseases, such as cryopyrinopathies or familial Mediterranean fever. In these diseases, a constitutional defect of the inflammasome, a protein complex responsible for the activation of interleukin-1, explains the hypersecretion of interleukin-1. Other autoinflammatory diseases have a more complex pathophysiology involving deregulation of the interleukin-1 pathway, upstream or downstream of the inflammasome, or through more complex mechanisms. In this review, we are detailing the synthesis, the activation, the signalling, and the regulation of interleukin-1. We then describe the autoinflammatory diseases or related-diseases where the pathological role of interleukin-1 has been demonstrated.

[Diagnostic approach of recurrent fevers of unknown origin in adults]

Recurrent fever of unknown origin is probably the most difficult to diagnose subtype of fever of unknown origin. It represents between 18 and 42% of the cases in large series of patients with fever of unknown origin. The limited literature data do not allow one to construct a diagnostic algorithm. However, the diagnostic strategy is different from classic fever of unknown origin. The spectrum of causative disorders is different from continuous fever with less infections and tumors. Among systemic inflammatory diseases, adult-onset Still's disease is the most common cause. More than 50% of the cases remain unexplained. Hereditary recurrent fevers, the prototype of autoinflammatory diseases, are now more easily discuss in a young adult.

[Skin manifestations of monoclonal gammopathies]

Whatever their aetiology, monoclonal gammopathies can be associated to several clinical features. Mechanisms are various and sometimes unknown. Skin is frequently involved and may represent a challenging diagnosis. Indeed, skin manifestations are either the presenting features and isolated, or at the background of a systemic syndrome. Our objective was to review the various skin manifestations that have been associated with monoclonal gammopathies.