Abstract
Hemophilia A is a blood clotting disorder characterized by a mutation of the factor VIII (FVIII) gene, leading to a deficiency in FVIII. It is the most common type of hemophilia. Inheritance is X-linked; hence males are affected while females are carriers or very rarely display a mild phenotype. 1:10,000 males are affected. We describe a child with a rare association of congenital hemophilia A and acquired severe aplastic anemia (SAA) who was successfully treated with allogeneic bone marrow transplantation (allo-BMT). A 6-year old male, SG, was diagnosed with hemophilia A (FVIII 3%) at 6-month old when he presented with right knee hemarthroses and psoas muscle hematoma. His maternal grandfather was hemophiliac. Since his diagnose, FVIII was infused on average once a month, generally due to hemarthroses and bleeding secondary to trauma. In July 2004, pt presented with progressive pancytopenia. In January 2005 CBC showed: Hb 7g/dl, Ht 22%, WBC 1000/μl (absolute neutrophil count 250/μl) and PLT 23,000/μl. Bone marrow aspirate and biopsy were consistent with SAA. DEB test was negative. Since then he was poly-transfused with PLT and RBC due to increased bleeding tendency, especially hematoma and petechiae. In July 2005 he underwent an allo-BMT from his HLA-identical non-hemophiliac 5-year old brother. For catheter implantation pt received PLT transfusion to achieve a PLT level greater than 50,000/mm3 and 60 units/kg of FVIII to achieve an initial level of 100% followed by 30 units/kg every 12 hours to maintain it continuously at greater than 50% for 3 days. Conditioning consisted of cyclophosphamide 50mg/day from D-5 to D-2 and thymoglobulin 5mg/kg from D-3 to D-1. Cyclosporine and a short course of methotrexate were given for GVHD prophylaxis. 3,5x108 mononuclear cells/kg were infused. Allo-BMT was uneventful. Neutrophil engrafted on D+15 and megakaryocyte (>50,000/mm3) on D+38. During the transplant PLT were kept at greater than 30,000/mm3 with PLT transfusion every 2 days. FVIII was infused when there was more than 2 cm increase in the knee perimeter or any other abnormal bleeding, especially at the catheter implantation site. 6 months after allo-BMT the child is well, with a normal CBC and coagulation tests similar to pre-BMT. Hemophilia and AA association is rare, and to our knowledge, this is the first allo-BMT in a hemophiliac patient to be reported.
Pharmacokinetics of anti-thymocyte globulin in a patient with severe aplastic anemia treated with allogeneic bone marrow transplantation from a matched unrelated donor