The multi-face expression of familial Mediterranean fever in the child.

Familial Mediterranean fever (FMF) is characterized by recurrent self-limiting flares of fever in the absence of pathogens, autoantibodies or antigen specific T cells and is inherited as an autosomal recessive trait probably deriving from common ancestors of Armenian, Jew, Turk and Arab origin. The underlying pathogenetic mechanisms of FMF have not been fully interpreted, but mutations in the gene MEFV encoding pyrin, a natural repressor of proinflammatory molecules, result in uncontrolled relapsing systemic inflammation, increased leukocyte migration to serosal membranes or joints and inappropriate response to inflammatory stimuli. FMF heterogeneous phenotypic expression could originate both from allelic heterogeneity or from the existence of modulating genes. Proper diagnosis of FMF is needed to begin both specific clinical management and treatment based on continuous prophylactic administration of colchicine, preventing flares or at least the onset of amyloidosis.

The clinical spectrum and treatment options of macrophage activation syndrome in the pediatric age.

Macrophage activation syndrome is a rare and potentially fatal complication of many childhood pathological settings, most frequently reported in systemic onset-juvenile idiopathic arthritis. The disruption of the macrophage-lymphocyte interaction leads to uncontrolled proliferation of highly activated macrophages and T lymphocytes. The syndrome comprises a heterogeneous group of disorders featuring sepsis-like characteristics typically combined with impaired function of natural killer cells and cytotoxic T-cells, haemophagocytosis and hypercytokinemia, often resulting in fatal multiple organ failure. The clinical picture shows high grade fever, hepatosplenomegaly, pancytopenia, lymphoadenopathy, central nervous system involvement and consumptive coagulopathy. Macrophage activation syndrome is associated with high mortality: even though diagnostic criteria have been proposed, definite diagnosis can be a challenge for clinicians, especially in early phases. There is no standardized therapeutic protocol for macrophage activation syndrome, but it is widely recognized that aggressive treatment strategies might strongly influence prognosis. First line-therapy is usually represented by parenteral administration of high dose-corticosteroids, whilst cyclosporine is added in the steroid-resistant cases. In this paper we provide clinical clues and summarize the most recent studies about pathophysiology and management suggestions for macrophage activation syndrome.