Molecular matching of red blood cells is superior to serological matching in sickle cell disease patients

OBJECTIVE: To evaluate the usefulness of DNA methods to provide a means to precisely genotypically match donor blood units for the antigen-negative type of 35 sickle cell disease patients<. METHODS: Red blood cell units were investigated for ABO, D, C, c, E, e, K, Fyª, Fy b, Jkª, Jk b, S, s, Diª and RH variants by performing a molecular array (Human Erythrocyte Antigen BeadChipTM, BioArray Solutions), polymerase chain reaction followed by restriction fragment length polymorphism analysis and sequencing of patient samples and donor units that had been serologically matched based on the ABO, Rh and K phenotypes and the presence of antibodies. RESULTS: Matches for 21 of 35 sickle cell disease patients presented discrepancies or mismatches for multiple antigens between the genotype profile and the antigen profile of their serologically-matched blood units. The main discrepancies or mismatches occurred in the RH, FY, JK and MNS systems. Eight Rh alloimmunized patients presented RHD and RHCE variants that had not been serologically identified. According to these results better matches were found for the patients with genotyped units and the patients benefited as shown by better in vivo red blood cell survival. CONCLUSION: Molecular matching is superior to serological matching in sickle cell disease patients, decreasing the risk of transfusion reactions, especially delayed transfusion reactions to existing alloantibodies and preventing alloimmunization.

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.

Otimização de metodologia para o estudo de genes KIR / Methodology optimization for KIR genotyping

Receptores killer cell immunoglobulin-like (KIRs) são moléculas localizadas na superfície de células natural killer (NK) e em subpopulações de linfócitos T codificadas por genes do cromossomo 19q13.4. A interação entre receptores KIR e moléculas antígeno leucocitário humano (HLA) de classe I determina se células NK exercerão ou não sua função citotóxica e/ou secretora de citocinas ou se esta será inibida. Este trabalho teve por finalidade otimizar a metodologia para a genotipagem KIR, baseando-se nas condições descritas por Martin (2004). A técnica utilizada foi a reação em cadeia da polimerase com primers de sequência específica (PCR-SSP) com iniciadores sintetizados pela Invitrogen® e visualização do produto amplificado em gel de agarose a 2 por cento com brometo de etídio. Adaptações foram realizadas e a concentração de alguns reagentes foi alterada, como a do controle interno de 100 nM para 150 nM, iniciadores específicos senso e antissenso de KIR12.5/12.3, KIR13.5/13.3, KIR14.5/14.3, KIR22.5/22.3 e KIR36.5/36.3 de 500 nM para 750 nM e da solução de MgCl2 de 1,5 mM para 2 mM. As concentrações dos demais reagentes e temperaturas de amplificação foram mantidas. Nessas condições, o uso da Taq DNA polimerase recombinante (Invitrogen®) foi satisfatório. Os resultados das genotipagens de 70 indivíduos foram confirmados por rSSO-Luminex® (One Lambda, Canoga Park, CA, EUA). A tipagem de genes KIR por essa técnica apresentou sensibilidade, especificidade, reprodutibilidade e baixo custo.

The killer cell immunoglobulin-like receptors (KIRs) are molecules expressed on natural killer (NK) cells surface and in T-cell subsets encoded by genes located in chromosome 19q13.4. The interaction between KIR receptors and HLA class I molecules determines if the NK cells will fulfill their cytotoxic function and/or cytokine secretion or if this function will be inhibited. The objective of this work was to optimize KIR genotyping method described by Martin (2004). It was used PCR-SSP (polymerase chain reaction-sequence-specific primers) with primers synthesized by Invitrogen® and visualization of the amplified products on 2 percent agarose gel electrophoresis, containing ethidium bromide. Some adaptations were made and the reagents had their concentrations increased: the internal control from 100 nM to 150 nM, forward and reverse specific primers KIR12.5/12.3, KIR13.5/13.3, KIR14.5/14.3, KIR22.5/22.3 and KIR36.5/36.3 from 500 nM to 750 nM, and MgCl2 solution from 1.5 mM to 2 mM. Other reagent concentrations and amplification temperatures were maintained. Satisfactory results were obtained with Taq DNA Polymerase Recombinant (Invitrogen®). The results of seventy samples were confirmed by rSSO-Luminex® (One Lambda, Canoga Park, CA, USA). This KIR typing method proved to be accurate, specific, reproducible and cost effective.

Extração de DNA a partir de sangue humano coagulado para aplicação nas técnicas de genotipagem de antígenos leucocitários humanos e de receptores semelhantes à imunoglobulina / DNA extraction from coagulated human blood for application in genotyping techniques for human leukocyte antigen and immunoglobulin-like receptors

O objetivo deste estudo foi padronizar uma metodologia de extração de DNA de alta qualidade a partir de amostras de sangue coagulado. Quarenta e oito amostras de sangue humano coagulado foram utilizadas para a extração de DNA pelo kit comercial EZ-DNA® (Biological Industries, Beit Haemek, Israel), pelo kit de coluna Neoscience® (One Lambda Inc., San Diego, CA) e pelo método modificado de salting out. Apenas o método de salting out foi capaz de extrair altas concentrações de DNA (média, 180ng/µL), as quais foram medidas pelo detector de fluorescência Qubit® (Invitrogen, USA). Este método permitiu a amplificação dos genes HLA (human leukocyte antigens) pela tecnologia PCR-SSO (polymerase chain reaction - specific sequence of oligonucleotides) Luminex, a qual exige DNA de boa qualidade, e de genes KIR (killer cell immunoglobulin-like receptors) pela técnica made in house PCR-SSP (polymerase chain reaction-sequence specific of primers), a qual demanda uma concentração específica de DNA (10ng/µL). Concluímos que a técnica de salting out modificada foi muito eficiente, simples e rápida para a extração de DNA de amostras de sangue humano coagulado, com o objetivo de realizar a genotipagem de genes HLA e KIR.

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/»l), 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/»l). 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.

Receptores Kir de células Natural Killer / Kir receptors of natural killer cells

As células NK (natural killer) são uma subpopulação de linfócitos que desempenham função essencial na resposta imune inata. As moléculas KIR (killer immunoglobulin-like receptor) são receptores expressos na superfície dessas células com função inibitória ou ativatória e contribuem para a regulação da função dascélulas NK. Os genes KIR fazem parte do Complexo de Receptores Leucocitários, localizado no cromossomo 19q13 e apresentam alto polimorfismo. Os ligantes de KIR são moléculas HLA de classe I, e a regulação dascélulas NK está relacionada à variação da expressão dessas moléculas na superfície das células-alvo, principalmente células infectadas, tumorais e alogênicas. O objetivo desse trabalho foi proceder a uma revisão bibliográfica sobre os receptores KIR. O levantamento foi realizado nos sites Pubmed/medline e ScienceDirect,e foram utilizadas como palavras-chave receptor, NK e KIR. A estrutura molecular desses receptores, a nomenclatura e classificação de KIR, a variabilidade gênica, alélica e haplotípica e os ligantes foram apresentados. Ênfase foi dada à regulação da expressão dos genes KIR e sua relação com a função das célulasNK.

NKC (natural killer cells) are a population of lymphocytes that play an essential role in innate immunity. KIR molecules are receptors expressed on the surface of these cells with an inhibitory or activating function that contributes to the regulation of NK cells. The KIR genes are located on chromosome 19q13 at the Leukocyte Receptor Complex, and exhibit high polymorphism. The KIR ligands are HLA class I molecules. NK cell functionsare related to the variation of the expression of these molecules on the surface of the target cells – especially infected, allogeneic and tumor cells. The aim of this work was to make a review about KIR receptors. The Pubmed/medline and ScienceDirect online databases were accessed, using receptor, NK and KIR as keywords. KIR molecular structure, nomenclature and classification, gene diversity, allelic and haplotypic variability and itsligands were described. Regulation of KIR genes expression and NK cell function were also presented.

Las células NK (natural killer) son una subpoblación de linfocitos que desempeñan una función esencial en la respuesta inmune innata. Las moléculas KIR (killer immunoglobulin-like receptor) son receptores expresos en la superficie de esas células con función inhibidora o activadora y contribuyen para la regulación de la función delas células NK. Los genes KIR hacen parte del Complejo de Receptores Leucocitarios, localizado en el cromosoma 19q13 y presentan alto polimorfismo. Los ligantes de KIR son moléculas HLA de clase I, y laregulación de las células NK está relacionada a la variación de la expresión de esas moléculas en la superficiede las células blanco, principalmente células infectadas, tumorosos y alogénicas. El objetivo de ese trabajo fue proceder una revisión bibliográfica sobre los receptores KIR. La pesquisa fue realizada en los sites Pubmed/medline y ScienceDirect, y fueron utilizadas como palabras clave receptor, NK y KIR. La estructura molecular de esos receptores, la nomenclatura y clasificación de KIR, la variabilidad génica, alélica y haplotípicay los ligantes fueron presentados. Énfasis fue dada a la regulación de la expresión de los genes KIR y surelación con la función de las células NK.