Bedside Leukoreduction of Cellular Blood Components in Preventing Cytomegalovirus Transmission in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Recipients.

Background: Leukoreduction of cellular blood components is a standard practice in the Blood Bank to prevent cytomegalovirus transmission. This process is of utmost importance in our pediatric hematopoietic stem cell transplant (HSCT) patients who are immunocompromized and thus are susceptible to this infection. The objective of this study is to show that bedside leukoreduction of cellular blood products is a safe alternative to blood components from a very limited pool of CMV seronegative donors in pediatric HSCT recipients.

Methods: We conducted a retrospective analysis of our pediatric HSCT performed between 02/23/96 and 03/11/05. Screening for CMV antibody in our donors was discontinued in 02/23/96. Instead, we switched to bedside leukoreduction for patients who need CMV negative blood products, including the pediatric HSCT recipients. Transplant recipients and donors were tested for CMV antibody prior to transplant date. Patients and donors who were CMV seronegative pairs were included in this study. Transfusion history of these patients was reviewed. CMV surveillance was performed by antigenemia assays once to twice weekly. Clinical evidence for CMV infection such as viral cultures of urine, blood, bronchial washings and pathology reports were reviewed.

Results: A total of 12 CMV-seronegative patient-donor pairs were identified among 128 transplants performed in this time period. Patients excluded from this study are 18 years of age and above and those who had received CMV screened blood products. Characteristics of these patients are: Age ranges from 35 months to 17 years; 9 were males and 3 were females; Diagnoses: acute lymphoblastic leukemia(5); acute myelogenous leukemia(3), Hodgkin’s disease,(1);Aplastic anemia,(1);Malignant Osteopetrosis(1) and CML (1). Three patients received mismatched unrelated donor cord blood transplant;3 had matched unrelated bone marrow transplants; 5 had matched sibling donor; and one had two transplants from his mother. All patients received red cells and platelets from random donors;10/12 received single donor platelets;3/12 had fresh frozen plasma;3/12 had granulocyte transfusions;1/12 had cryoprecipitate and 11/12 received IVIg. All blood products were infused at bedside using a leukoreduction filter(Baxter Healthcare Corp., Deerfield, IL). 2/12(17%) had positive CMV antigenemia assays. One patient had CMV antigenemia testing positive 22 days pre-transplant and 149 days post-transplant. He did not have evidence of CMV disease and there was no subsequent CMV seroconversion. The other patient had positive CMV antigenemia 27 days post-transplant. The first patient mentioned had been infused with 8 units of granulocytes, while the later did not receive any granulocyte unit. Both patients had anti-viral therapy. A third patient seroconverted 3 months post-transplant. All CMV antigenemia testing on this patient were negative and he had no evidence of CMV disease.

Conclusion: Our study showed that bedside leukoreduction of cellular blood products, coupled with CMV surveillance may be a safe alternative to blood components from CMV seronegative donors for pediatric HSCT patients.