Context: Children with severe combined immunodeficiency who receive a T cell-depleted hematopoietic stem cell transplantation (HSCT) have delayed immune reconstitution.
Objective: To examine the use of recombinant human insulin-like growth factor-I (rhIGF-I) therapy to stimulate thymopoiesis after HSCT.
Clinical case: A child with Omenn syndrome failed T cell reconstitution 6 months after HSCT. She started rhIGF-I therapy just before age 18 months. The initial dose (40 microg/kg twice daily) was increased every 2 weeks to a maximum dose of 120 microg/kg twice daily.
Results: The patient's absolute T cells increased from 7 to 132/mm(3) and 662/mm(3) after 3 and 5 months of rhIGF-I therapy, respectively, and her blastogenic response to phytohemagglutinin normalized. Three months after discontinuation of rhIGF-I therapy, the T cells continued to increase (to 2,427/mm(3)) although the blastogenic response to phytohemagglutinin decreased.
Conclusion: This is the first known use of rhIGF-I therapy to help restore thymopoiesis in a child.