title: Hemoglobin Variants Acquired Post-Exchange Transfusion in Pediatric Sickle Cell Disease (SCD) Patients.
abstract: BACKGROUND
  Many SCD patients receive chronic transfusions for prevention or treatment of disease related complications. Complications of the chronic transfusion noted in these patients include allergic reactions, transfusion transmitted infections, iron overload, and alloantibody formation. Even though hemoglobin (Hb) variants are prevalent in the general population, reports of transfusion-acquired Hb variants are rare. We performed a retrospective analysis on all SCD patients who underwent red cell exchange (RBCEx) transfusions at our institution during 2011-2013 to identify the presence of Hb variants acquired as a result of RBCEx.
  
  
  RESULTS
  We found 66 occurrences of acquired Hb variants in 30 SCD patients during the period examined. The most commonly acquired Hb variant was Hemoglobin C (HbC) (64/66 occurrences). More than half of the patients (19/30) acquired HbC on multiple occasions (2-6 times). One patient acquired HbJ and another patient acquired HbD/G in addition to HbC. The segments from donor units were available in some of these cases and hemoglobin electrophoresis (HBE) was performed to confirm the presence of the variant Hb in the donor segments corresponding to that seen on the post-RBCEx sample.
  
  
  CONCLUSIONS
  Heterozygous donors are asymptomatic and show no abnormalities during donor screening. Since HBE is not routinely performed on the donor specimen, it may go unrecognized until the post-transfusion recipient results pose diagnostic difficulties. There are no definitive guidelines on deferring these donors; hence one should be cognizant of these findings to prevent misdiagnosis. In a population where HbS negative blood is routinely requested, the effect of other Hb variants remains unknown. None of the patients in our study showed any adverse events due to the acquired Hb variants; however, this is of special concern in the pediatric population where a single RBC unit can contribute a significant portion of the exchanged blood volume. Additionally, donor centers may need mechanisms to confirm the findings and counsel the donors as needed.
authors.affiliation: Departments of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, USA Arkansas Children's Hospital, Little Rock, AR, USA spandey@uams.edu.
authors.forename: Soumya
authors.initials: S
authors.lastname: Pandey
authors.affiliation: Departments of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: Michele
authors.initials: M
authors.lastname: Cottler-Fox
authors.affiliation: Departments of Pathology, University of Arkansas for Medical Sciences, Little Rock, AR, USA Arkansas Children's Hospital, Little Rock, AR, USA.
authors.forename: Gina
authors.initials: G
authors.lastname: Drobena
mesh_terms: D000293:Adolescent; D000328:Adult; D000755:Anemia, Sickle Cell / Q000097:blood* / Q000628:therapy*; D001782:Blood Donors; D002648:Child; D017707:Erythrocyte Transfusion / Q000379:methods*; D006444:Hemoglobin C / Q000032:analysis; D006448:Hemoglobin J / Q000032:analysis; D006451:Hemoglobin, Sickle / Q000032:analysis; D006455:Hemoglobins, Abnormal / Q000032:analysis*; D006801:Humans; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D006451:Hemoglobin, Sickle; D006455:Hemoglobins, Abnormal; C032001:hemoglobin D; D006448:Hemoglobin J; D006444:Hemoglobin C