Fabiano Cavalcante de Melo

Benefits of blood group genotyping in multi‐transfused patients from the south of Brazil

We evaluated the usefulness of blood group genotyping as a supplement to hemagglutination to determine the red blood cell (RBC) antigen profile of polytransfused patients with hematological diseases and renal failure. Seventy‐nine patients were selected. They all received more than three units of blood and eight (10%) had already clinical significant alloantibodies occurring alone or in combination against Rh, K, Fya, and Di antigens. DNA was prepared from blood samples and RHCE*E/e, KEL*01/KEL*02, FY*01/FY*02 and JK*01/JK*02 alleles were determined by using PCR‐RFLP. RHD*/RHD*Ψ and RHCE*C/c were tested using multiplex PCR. Discrepancies for Rh, Kell, Duffy, and Kidd systems were found between the phenotype and genotype‐derived phenotype in 16 of the 38 chronically transfused patients. The genotypes of these patients were confirmed by DNA array analysis (HEA Beadchip™; Bioarray Solutions, Warren, NJ). Genotyping was very important for the determination of the true blood groups of the polytransfused patients, helped in the identification of suspected alloantibodies and in the selection of antigen‐negative RBCs for transfusion. J. Clin. Lab. Anal. 24:311–316, 2010.

DNA extraction from coagulated human blood for application in genotyping techniques for human leukocyte antigen and immunoglobulin-like receptors

The objective of this study was to standardize a method for extracting high-quality DNA from samples of coagulated blood. Forty-eight samples of human coagulated blood were used for DNA extraction by means of the EZ-DNA commercial kit (Biological Industries, Beit Haemek, Israel), the Neoscience column kit (One Lambda Inc., San Diego, CA, USA) and a modified salting-out method. Only the salting-out method was able to extract high concentrations of DNA (mean, 180 ng/(1/4)microl), which were measured using the Qubit fluorescence detector (Invitrogen, USA). This method enabled amplification of HLA (human leukocyte antigen) genes using the Luminex PCR-SSO (polymerase chain reaction - sequence-specific oligonucleotide) technology, which demands good quality DNA, and amplification of KIR (killer-cell immunoglobulin-like receptor) genes using an in-house PCR-SSP (polymerase chain reaction - sequence-specific primer) technique, which demands a specific concentration of DNA (10 ng/(1/4)microl). We concluded that the modified salting-out technique was very efficient, simple and fast for DNA extraction from human coagulated blood samples, with the aim of genotyping the HLA and KIR genes.

Rh, Kell, Duffy, Kidd and Diego blood group system polymorphism in Brazilian Japanese descendants

Polymorphisms of Rh, Kell, Duffy, Kidd and Diego blood group systems were studied in 209 unrelated Brazilian Japanese descendants from South of Brazil. The methods used were multiplex-PCR, AS-PCR and RFLP-PCR. The differences in frequencies among the populations were evaluated using chi-square test. The frequencies for Rh, Kell, Kidd and Diego system were similar to those of the Japanese. RHCE(*)CC, RHCE(*)EE genotypes and FY(*)01 allele were lower and FY(*)01N.01 was higher than Japanese. These differences in the frequencies between Brazilian Japanese descendants and Japanese could indicate a gene flow in Brazilian population and reinforce the importance of this knowledge to achieve safe red blood cells.

Genetic polymorphisms of Rh, Kell, Duffy and Kidd systems in a population from the State of Paraná, southern Brazil

Background Red blood group genes are highly polymorphic and the distribution of alleles varies among different populations and ethnic groups. Aim To evaluate allele polymorphisms of the Rh, Kell, Duffy and Kidd blood group systems in a population of the State of Paraná Methods Rh, Kell, Duffy and Kidd blood group polymorphisms were evaluated in 400 unrelated blood or bone marrow donors from the northwestern region of Paraná State between September 2008 and October 2009. The following techniques were used: multiplex-polymerase chain reaction genotyping for the identification of the RHD gene and RHCE*C/c genotype; allele-specific polymerase chain reaction for the RHDψ and restriction fragment length polymorphism polymerase chain reaction for the RHCE*E/e, KEL, FY-GATA and JK alleles. Results These techniques enabled the evaluation of the frequencies of Rh, Kell, Duffy and Kidd polymorphisms in the population studied, which were compared to frequencies in two populations from the eastern region of São Paulo State. Conclusion The RHCE*c/c, FY*A/FY*B, GATA-33 T/T, JK*B/JK*B genotypes were more prevalent in the population from Paraná, while RHCE*C/c, FY*B/FY*B, GATA-33 C/C, JK*A/JK*B genotypes were more common in the populations from São Paulo.

Investigation of deletion of 22pb in KIR2DS4 gene in a population of southern Brazil.

The aim of this study was to investigate the distribution of full‐length and deleted variants of KIR2DS4 in a population of southern Brazil and compare the results with other populations, as well as comparing two techniques, PCR‐SSP and PCR‐SSO, for typing of variants.

Frequency of RHD variants in Brazilian blood donors from Parana State, Southern Brazil

The Rh blood group system is one of the most complex, polymorphic and immunogenic blood group systems in humans. Some individuals produce a weak or a partial D as a result of RHD and RHCE gene conversion events and RHD point mutations. Because the incidence of RHD variants differs considerably among ethnic groups, the objective of this study was to establish the frequency of blood donors carrying some weak and partial RHD, at the molecular level, in 400 blood donors from the North/Northwest of the state of Parana, Southern Brazil. Another 30 blood donors whose RhD typing results in serology were inconclusive were also included. In this mixed Brazilian population, the most frequent weak D types were 1, 4, 3 and 2 (frequencies of 4.35%, 2.32%, 1.46% and 0.29%, respectively; total of 8.41%) and partial D was found in 2.90% of samples carrying the RHD gene. For samples with inconclusive RhD typing, 53.33% of them presented weak and partial RHD, and 43.75% had concomitantly more than one RHD variant. Our results demonstrate the presence of Caucasian and African D variants. This knowledge can contribute to the safety of transfusion strategies in this ethnic admixture population.