Two important syndromes of hemophagocytic lymphohistiocytosis (HLH) have to be considered in infants and young children with recurrent fever, organomegaly and cytopenias. Familial hemophagocytic lymphohistiocytosis (FHLH) is a genetically heterogeneous autosomal recessive disease with histiocytic and lymphocytic infiltrations in multiple organs and is currently curable only by bone marrow transplantation (BMT). Secondary HLH most commonly results from viral infections and some patients may be cured by treating the causative organism, others will need chemotherapy and immunosuppression. Since infections can also trigger disease episodes in FHLH, making the correct diagnosis can prove difficult. The published experience of BMT in HLH is reviewed. Taken together, cure of the majority of patients with HLH by matched related BMT, unrelated or haploidentical BMT is possible. Incomplete resolution of disease activity does not necessarily impede a successful outcome. Central nervous system involvement will eventually develop in many HLH patients and may cause considerable morbidity. Appropriate early treatment and a timely BMT will hopefully decrease mortality rates and improve neurodevelopmental outcome in this disease.
