[The accelerated phase of Chediak-Higashi syndrome]

We have retrospectively analysed the clinical and biological features as well as the outcome of 18 accelerated phases having occurred in 11 patients with the Chediak-Higashi syndrome. This complication is very frequent and is characterized by a multi-visceral lymphohistiocytic infiltration with hemophagocytosis leading to pancytopenia, a bleeding disorder secondary to low fibrinogen level, hypertriglyceridemia and hemodilution. The accelerated phase of the Chediak-Higashi syndrome is identical to the manifestations of familial erythrophagocytic lymphohistiocytosis and of the viral-associated hemophagocytic syndrome. The outcome was invariably fatal before the use of etoposide (VP 16) in association with steroids and intrathecal methotrexate. Complete remission with this management regimen was observed in 7/7 cases. However, remissions were only transient. HLA identical bone marrow transplantation appeared to be the only therapeutic strategy capable of curing the disease (3/3 patients). Non transplanted patients relapsed and died as well as one patient who received a HLA non identical bone marrow transplantation. Due to the frequency and the severity of the accelerated phase of the Chediak-Higashi syndrome, HLA identical bone marrow transplantation should be proposed as early as possible after the onset of the accelerated phase.