DARC alleles and Duffy phenotypes in African Americans.

BACKGROUND: The DARC (Duffy blood group, chemokine receptor) gene encodes for a transmembrane glycoprotein that functions as a chemokine transporter, is a receptor for Plasmodium vivax and P. knowlesi, and expresses the Duffy blood group antigens (Fy). The Fy(a-b-) phenotype found in people of African descent is typically associated with a -67t>c mutation in the 5'-untranslated region (UTR), which prevents red blood cells being invaded by P. vivax and P. knowlesi. The aim of this study was to establish DARC allele frequencies in an African American blood donor cohort, determine a phylogenetic tree for DARC, and compare human and Neandertal DARC genes. STUDY DESIGN AND METHODS: The DARC nucleotide sequence of 54 African American blood donors was determined from genomic DNA. Heterozygous substitutions were resolved by sequencing of haplotype-specific amplifications. A phylogenetic tree for DARC was established using the neighbor-joining method with Pan troglodytes as root. RESULTS: A total of 108 haplotypes of the DARC gene could be unambiguously determined from nucleotide position -300 in the 5' UTR to +300 in the 3' UTR. Eleven different alleles were found, including the clinically relevant FY*A, FY*B, FY*B-67C, FY*B298A, and FY*X alleles. All phenotype predictions based on genotypes matched the serologically determined phenotypes exactly: 52% Fy(a-b-), 28% Fy(a-b+), and 20% Fy(a+b-). CONCLUSIONS: The nucleotide sequencing approach using one amplicon is a practical genotyping method for DARC and allows the determination of haplotypes even in heterozygous constellations. We developed a phylogenetic tree for DARC alleles and postulated a distinct FY*B allele as ancestral for the extant DARC alleles in humans.

A practical strategy to reduce the risk of passive hemolysis by screening plateletpheresis donors for high-titer ABO antibodies.

BACKGROUND: Hemolytic transfusion reactions (HTRs) can occur from ABO-incompatible platelet (PLT) transfusions. After a series of cases at our institution, a procedure to screen all plateletpheresis donors for high-titer ABO antibodies was implemented. STUDY DESIGN AND METHODS: Plasma samples from plateletpheresis donors were screened using pooled 0.8% A1 and 0.8% B red blood cells (RBCs) in buffered gel. Dilutions of 1 in 150, 1 in 200, and 1 in 250 were sequentially evaluated. A component testing positive for high-titer ABO antibodies was restricted to ABO-identical or group O recipients or washed. RESULTS: At the initial dilution of 1 in 150, half of group O components were labeled as high titer. At the current dilution of 1 in 250, 25% of group O components are labeled as high titer. No PLT-associated HTR has been reported since screening began. CONCLUSION: Universal screening for high-titer ABO antibodies in plateletpheresis donors can be implemented efficiently to reduce the risk of HTRs. The cutoff for classifying a unit as high titer depends on the serologic method used and may be customized by the individual facility. Our screening method uses one gel test per donation regardless of blood group and a plasma dilution of 1 in 250 with pooled A1/B RBCs in buffered gel.

Organization and management of an accredited specialist in blood bank (SBB) technology program.

BACKGROUND: Specialists in blood bank (SBBs) technology play important roles in blood banks, transfusion services, regulatory agencies, educational institutions, and other facilities where expertise in blood banking, transfusion medicine, cellular therapy, and tissue transplantation is required. STUDY DESIGN: Review of pathways that qualify applicants for a national examination administered by the American Society of Clinical Pathology (ASCP) to become a certified specialist and outcomes of accredited programs. Description of a face-to-face, accredited program including review of management topics included in curriculum. RESULTS: The first examination was administered in 1954. As of December 2009, the total number of certified SBBs was 5124. There are currently 16 accredited SBB programs in the United States. The programs vary in mode of delivery, length of program, number of students accepted, and organization of program officials and faculty, but all must follow specific standards and guidelines in order to be accredited. CONCLUSION: Students who successfully complete SBB programs have a higher passing rate than those who attempt the certification examination and have not participated in a program. Students can choose among a variety of programs that differ widely in the way they are managed. The role of management in an SBB program ranges from attracting and retaining individuals and maintaining an accredited program to finally graduating individuals who not only pass the certification examination but who also confidently contribute to the field.