A 3-year-old boy is taken to the pediatrician because of a nosebleed (epistaxis).He has a history of severe,recurrent sinopulmonary infection.Physical examination is remarkable for dry,red patches of skin (eczema)and multiple petechiae (tiny hemorrhagic spots).Laboratory findings include thrombocytopenia and reduced IgM levels.The boy's maternal uncle died of bleeding complications after an emergency appendectomy.Which of the following represents a curative therapy currently available for this patient?

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Bone marrow transplantation,in which the immunodeficient patient's marrow is reconstituted with functional immune cell precursors,is the only curative therapy currently available for Wiskott-Aldrich syndrome (WAS)or severe combined immunodeficiency disease (SCID).In particular,bone marrow transplantation from HLA-matched sibling donors have had very high success rates.Passive immunization with gamma globulin only prevents or minimizes future infections.Corticosteroids,which exhibit immunosuppressive effects,are contraindicated in already immunodeficient patients.Enzyme replacement therapy has shown transient benefit in patients with well-characterized enzyme deficiencies,including adenosine deaminase (ADA)and purine nucleoside phosphorylase (PNP)deficiencies.Gene therapy to restore the affected WASP gene in WAS syndrome,although potentially curable,remains a distant clinical goal.

A 3-Year-Old Boy Is Taken to the Pediatrician Because of a Nosebleed