Familial erythrophagocytic lymphohistiocytosis: treatment with vinblastine-loaded platelets.

Identical twin Caucasian boys, age 3 months, were seen with fever of unknown origin, hepatosplenomegaly, and pancytopenia. The diagnosis of familial erythrophagocytic lymphohistiocytosis (FEL) was suspected after examination of Twin A's bone marrow and confirmed by an open liver biopsy of Twin B. Twin A died shortly after diagnosis despite treatment with vincristine and prednisone. At autopsy, the diagnosis was confirmed. Twin B responded initially to a three-week course of weekly vincristine and daily prednisone, but symptoms soon recurred. In an effort to enhance delivery of chemotherapy to the active macrophage target, platelets were loaded with vinblastine and then administered intravenously to th patient every 7-10 days. There was an encouraging response reflected by the disappearance of symptoms and the return of peripheral blood count to the normal range, although increased number of histiocytes was still demonstrable in his bone marrow. After nine weeks, he lapsed completely and became refractory to treatment. He died of pseudomonas sepsis four months after diagnosis. This is the first known attempt to deliver a chemotherapeutic agent directly to the macrophages in treating this disease and represents an interesting concept that merits further exploration.