Collapsing glomerulopathy associated with hemophagocytic syndrome in a patient with NK/T cell lymphoma.

Hemophagocytic syndrome (HPS) is a rare condition caused by dysregulated activation of the immune system leading to infiltration of bone marrow and organs by nonmalignant macrophages that phagocytose blood cells. Primary HPS is caused by inherited immune dysregulation whereas secondary HPS is triggered by neoplastic, infectious or autoimmune diseases. Clinically, the syndrome presents with continuous high-grade fever in association with multi-organ involvement.

The tumor necrosis factor-alpha converting enzyme (TACE): a unique metalloproteinase with highly defined substrate selectivity.

TNF alpha converting enzyme (TACE) processes precursor TNF alpha between Ala76 and Val77, yielding a correctly processed bioactive 17 kDa protein. Genetic evidence indicates that TACE may also be involved in the shedding of other ectodomains. Here we show that native and recombinant forms of TACE efficiently processed a synthetic substrate corresponding to the TNF alpha cleavage site only.