Comparison of multiple red cell volume methods performed concurrently in premature infants following allogeneic transfusion.

BACKGROUND: Study of the pathophysiology and treatment of anemia of prematurity is facilitated by direct measurement of red cell volume (RCV) utilizing microliter quantities of blood samples. Our objective was to compare concurrent measurements of multiple direct RCV methods in infants. METHODS: Eighteen preterm infants receiving clinically indicated transfusions had concurrent flow cytometric determinations of RCV and 24-h red blood cell (RBC) recovery based on donor-recipient differences of biotin-labeled RBCs (BioRBCs), Kidd antigen mismatched RBCs, and fetal hemoglobin-positive (HbF(+)) RBCs. High-performance liquid chromatography (HPLC) was also used for measuring HbF and adult hemoglobin protein concentrations for the determination of RCV. RESULTS: Concurrent RCV measurements using BioRBCs (18 and 54 µg/ml), Kidd antigen, and HbF flow cytometry were not statistically different compared with RCVs measured using the reference BioRBC density (6 µg/ml). By contrast, the HbF-HPLC method overestimated RCV by 45% compared with the reference method. All the methods demonstrated 100% 24-h posttransfusion RBC recovery (PTR24). CONCLUSION: Because BioRBC, Kidd antigen, and fetal hemoglobin (HbF) flow cytometry are safe and accurate methods requiring <10 µl of patient blood for determining RCV and PTR24 in preterm infants, they can be useful in clinical and research studies of anemia and other conditions.

The manual Polybrene test has limited sensitivities for detecting the Kidd blood group system.

BACKGROUND AND OBJECTIVES: The Kidd system antibodies, if undetected, can cause immediate or delayed hemolytic transfusion reactions as well as hemolytic disease of the newborn. There have been anecdotal reports about the inefficiency of the manual Polybrene test in detecting these antibodies. Here, we sought to determine the sensitivity of the manual Polybrene test in detecting anti-Jk(a) and anti-Jk(b) antibodies and Jk(a) and Jk(b) antigens. MATERIALS AND METHODS: Ten archived anti-Jk(a)/Jk(b) antibody positive human sera were examined by both the manual Polybrene test and the indirect antiglobulin test using polyspecific antibodies, monospecific anti-IgG antibodies and anti-C3 antibodies. Furthermore, 40 randomly selected donor blood samples were collected and phenotyped for the frequencies of Jk(a) and Jk(b) antigens using the manual Polybrene test and the indirect antiglobulin test. The results from these tests were further confirmed by saline tube tests. RESULTS: The manual Polybrene test displayed an overall sensitivity of 60% in detecting anti-Jk(a) and anti-Jk(b) antibody. Specifically, it had a sensitivity of 57.14% for anti-Jk(a) antibody and a sensitivity of 66.7% for anti-Jk(b) antibody. Furthermore, the manual Polybrene test exhibited a sensitivity of 46.15% for Jk(a) antigen and a sensitivity of 77.42% for Jk(b) antigen. CONCLUSION: The manual Polybrene test has a very low sensitivity in detecting anti-Jk(a) and anti-Jk(b) antibody, especially anti-Jk(a) antibody. It is also a very insensitive test for detecting Jk(a) antigen.

Erythroid urea transporter deficiency due to novel JKnull alleles.

BACKGROUND: The Kidd blood group antigens Jka and Jkb are encoded by the red blood cell (RBC) urea transporter gene. Homozygosity for silent JK alleles results in the rare Jk(a-b-) phenotype. To date, seven JKnull alleles have been identified, and of these, two are more frequent in the Polynesians and Finns. This study reports the identification of other JKnull alleles in Jk(a-b-) individuals of different ethnic or geographic origins. STUDY DESIGN AND METHODS: Nine Jk(a-b-) samples and a sample from a Jk(a-b+) mother of a Jk(a+b-) baby were investigated. Polymerase chain reaction amplification and sequence analysis of the JK gene was performed. Western blotting and urea lysis were used to confirm Jk(a-b-) RBCs. RESULTS: Four novel alleles were identified: two different nonsense mutations, 202C>T (Gln68Stop) and 723delA (Ile262Stop) were identified on otherwise consensus JK*1 and JK*2 alleles, respectively. A missense mutation, 956C>T (Thr319Met), was identified in a JK*1 allele from an African-American and a JK*2 allele in two people of subcontinental Indian descent. Immunoblotting and urea lysis confirmed absence of JK glycoprotein in RBC membranes from a sample carrying the 956C>T mutation. Other previously described JKnull mutations were found in samples of origins other than in which they were first identified. CONCLUSION: The molecular bases of the Jk(a-b-) phenotype are diverse and this is the first report of JKnull alleles in individuals of African and subcontinental Indian descent. Although rare, these alleles should be taken into consideration when planning genotyping strategies for blood donors and patients.

Molecular genetic blood group typing by the use of PCR-SSP technique.

BACKGROUND: DNA-based methods are useful for enhancing immunohematology typings. Ready-to-use Conformité Européenne (CE)-marked test kits based on polymerase chain reaction with sequence-specific priming (PCR-SSP) have been developed, which enable the examination of weak, unexpected, or unclear serologic findings. DEVELOPMENT AND VALIDATION: Primers were designed according to established mutation databases. Proficiency testing for CE marking was performed in accordance with Directive 98/79EC of the European Parliament and of the Council of October 27, 1998 on in vitro diagnostic medical devices using pretyped in-house and external samples. INTENDED USE: BAGene PCR-SSP kits are in vitro diagnostic devices. Genotyping of ABO and RHD/RHCE as well as HPA and KEL, JK, and FY specificities has to be performed after the conclusion of the serologic determination. APPLICATION: Ready-to-use PCR-SSP typing kits allow the determination of common, rare, or weak alleles of the ABO blood group, Rhesus, and Kell/Kidd/Duffy systems as well as alleles of the human platelet antigens. RESULTS: The investigations showed clear-cut results in accordance with serology or molecular genetic pretyping. CONCLUSION: PCR-SSP is a helpful supplementary technique for resolving most of the common problems caused by discrepant or doubtful serologic results, and it is an easy-to-handle robust method. Questionable cases in donor, recipient, and patient typing can be examined with acceptable cost.

K, Fy(a), and Jk(a) phenotyping of donor RBCs on microplates.

BACKGROUND: In many cases, the search for compatible blood for patients with clinically significant RBC alloantibodies is difficult and time-consuming. To date, it has been considered necessary only to phenotype the blood donors for ABO group and D. There has been long experience with automated routine analysis (ABO, C, c, D, E, and e typing and RBC antibody screening), using robotic dispensers and computerized interpretation of microplate results. The purpose of this study was to explore the possibilities of also phenotyping for K, Fy(a), and Jk(a), as antibodies directed against these antigens (together with Rh antigens) are the most common clinically significant alloantibodies in the Swedish population. STUDY DESIGN AND METHODS: One thousand thirty-one EDTA samples from blood donors were phenotyped for K, Fy(a), and Jk(a) by use of an IAT with PEG on microplates. The findings were compared to those using conventional IAT in tube's and the microcolumn gel test (DiaMed-ID, DiaMed). RESULTS: All typing results with the microplate method were correct. All reactions for K and Fy(a) typing could be interpreted by the computer. The results for Jk(a) were indeterminate in 1.4 percent (14/1031) of the samples. CONCLUSION: The PEG-IAT microplate method gave reliable results that were suitable for routine phenotyping, thus making available a stock of phenotyped blood at reasonable cost, ready for delivery when required.

Sistema Kidd: Distribución de los fenotipos y genotipos en la población de Costa Rica / Kidd system: Distribution of the phenotype and genotypes in the population of Costa Rica

Con el objetivo de determinar la distribución de los fenotipos y genotipos del sistema Kidd (Jk), se analizaron un total de 872 personas adultas sin aparente grado de consanguinidad, que se presentaron al Laboratorio de Inmunohematología del Organismo de Investigación Judicial, entre 1984 y 1992, para invastigar casos de paternidad discutida. el tamaño de la muestra se determinó de acuerdo con la fórmula n=z2pq/d2 y la frecuencia alélica por el método de conteo de genes. La distribución obtenida para el fenotipo Jk (a+b) es de 27,4 por ciento, para el Jk(a+b+) es de 52,6 por ciento y para el Jk (a-b+) es de 20,0 por ciento, muy semejante a la establecida por Gaensslen y col. en la población hispana de los Estados Unidos. Para el gen JKa encontramos una frecuencia de 0,5372 y para el 0,4627. Por Chi cuadro se determinó que la población estudiada se encuentra en equilibrio de Hardy Weinberg.