Anticuerpos irregulares en donantes de sangre / Anticuerpos irregulares en donantes de sangre Irregular antibodies in blood donor

Introducción: El sistema inmunológico puede reconocer una gran cantidad de antígenos cuando está expuesto a ellos. Los linfocitos B producen gran variedad de anticuerpos, con el fin de generar la especificidad de los receptores para el reconocimiento de dichos antígenos. La presencia de anticuerpos irregulares, es una de las causas de reacciones adversas transfusionales por incompatibilidad entre donante y receptor. Objetivo: Describir la genética, estructura y función de los anticuerpos irregulares en los donantes de sangre. Métodos: Se llevó a cabo una revisión de la literatura, en idioma inglés y español, a través de bases de datos como Pubmed, ScienceDirect, NCBI, Redalyc y SciElo de artículos publicados en los últimos 10 años. Análisis y síntesis de la información: El sistema inmunológico genera una gran diversidad de anticuerpos mediante el proceso de recombinación somática entre los segmentos Variables (V), de diversidad (D) y de unión (J) de la línea germinal de las inmunoglobulinas, como mecanismo de defensa del organismo frente a sustancias o antígenos extraños. Los anticuerpos irregulares son aquellos diferentes al sistema sanguíneo ABO y los más comúnmente encontrados en los donantes de sangre son anti-D, anti-E, anti-K y anti-M. Conclusiones: La importancia clínica de los anticuerpos irregulares en donantes se basa en su asociación con las reacciones hemolíticas, dada la capacidad que tienen los antígenos de algunos grupos sanguíneos para generar anticuerpos de tipo IgG que causan lisis prematura de los eritrocitos(AU)

Introduction: The immune system can recognize a large number of antigens when it is exposed to them; B Lymphocytes produces a great variety of antibodies, in order to generate the specificity of the receivers for the recognition of said antigens. The presence to irregular antibodies is one of the causes to the adverse reactions to the transfusion when for blood incompatibility between donor and receptor. Objective: To describe the genetics, structure and function of irregular antibodies in blood donors. Methods: A literature review was carried out, in English and Spanish, through databases such as Pubmed, ScienceDirect, NCBI, Redalyc and Scielo of articles published in the last 10 years. Analysis and synthesis of information: The immune system generates a great diversity of antibodies through the somatic recombination process between the Variable (V), diversity (D) and joining (J) segments of the germ line of immunoglobulins, as a defense mechanism of the organism against foreign substances or antigens. Irregular antibodies are those other than the ABO blood system and those most commonly found in blood donors are anti-D, anti-E, anti-K, and anti-M. Conclusions: The clinical significance of irregular antibodies in donors is based on their association with hemolytic reactions, due to the ability of antigens in some blood groups to generate IgG-type antibodies that cause premature erythrocyte lysis(AU)

Human leukocyte antigen (HLA) diversity and clinical applications in South Africa

The major histocompatibility complex, known as the human leukocyte antigen (HLA) complex in humans, forms an integral component of adaptive T cell immunity by presenting self and non-self peptides to the T cell receptor, thereby allowing clonal expansion of responding peptide-specific CD4+ and CD8+ T cells. HLA likewise forms an integral part of the innate immune response through the binding of killer-cell immunoglobulin-like receptor (KIR) molecules, which regulate the response of natural killer (NK) cells. The HLA complex is found on the short arm of chromosome 6 and is the most polymorphic region in the human genome. Africans are genetically more diverse than other populations; however, information on HLA diversity among southern Africans, including South African populations, is limited. Paucity of African HLA data limits our understanding of disease associations, the ability to identify donor-recipient matches for transplantation and the development of disease-specific vaccines. This review discusses the importance of HLA in the clinical setting in South Africans and highlights how tools such as HLA imputation might augment standard HLA typing methods to increase our understanding of HLA diversity in our populations, which will better inform disease association studies, donor recruitment strategies into bone marrow registries and our understanding of human genetic diversity in South Africa

The Role of B Cells in Transplantation Rejection / 대한이식학회지

B cells play a role in graft rejection via several mechanisms. Specifically, B cells produce high-affinity antibodies to alloantigens including allogeneic major histocompatibility complex (MHC) with the help of follicular helper T cells. B cells also function as antigen-presenting cells for alloreactive T cells, resulting in the activation of alloreactive T cells. Conversely, the frequency of regulatory B cells increases under inflammatory conditions and suppresses the rejection process. Here, the differential roles of the major B cell subpopulations (B-1, follicular B, marginal zone B, and regulatory B cells) involved in transplantation rejection are discussed together with their interaction with T cells.

Current applications of high-throughput DNA sequencing technology in antibody drug research / 药学学报

Since the publication of a high-throughput DNA sequencing technology based on PCR reaction was carried out in oil emulsions in 2005, high-throughput DNA sequencing platforms have been evolved to a robust technology in sequencing genomes and diverse DNA libraries. Antibody libraries with vast numbers of members currently serve as a foundation of discovering novel antibody drugs, and high-throughput DNA sequencing technology makes it possible to rapidly identify functional antibody variants with desired properties. Herein we present a review of current applications of high-throughput DNA sequencing technology in the analysis of antibody library diversity, sequencing of CDR3 regions, identification of potent antibodies based on sequence frequency, discovery of functional genes, and combination with various display technologies, so as to provide an alternative approach of discovery and development of antibody drugs.

Genesis, development and application prospect of antibody library: a review / 生物工程学报

Antibodies are immunoglobulins specifically introduced by immunity response of high animals, with the responsibility for recognising and cleaning out specific antigens. Antibody is not only a powerful weapon against pathogen invasion in the organism, but also a tool for specific molecular recognition used in basic scientific research. The diversity of antibody molecules resulted in the concept of antibody library; each individual animal is a natural antibody library. In the post-genome era, in order to fit various "omics", especially for proteomics requirement of high throughput technology, some gene engineering antibody libraries and antibody alternative libraries have been constructed based on phage display technology. Yet, more and more in vitro display systems such as ribosome display, mRNA display have been used for antibody library study, and that present more advantages than phage display. This mini review outlines the genesis, development and application prospect of antibody libraries according to the published reviews and research articles, and offers up to date development and application prospect of antibody library technology.

Búsqueda e identificación de anticuerpos irregulares en la población de Antofagasta / Screening and identification of irregular antibodies in population of Antofagasta

In the last years, the medicine transfusional has generated big advances in the area of the conservation and managing of the blood fractions, especially in the detection of incompatibilities between donors and recipients, using monoclonal antibodies powerful and new methods that detect antibodies in very low concentrations. The majority of the blood banks agree to provide compatible blood for the antigens ABO and Rho (D), because opposite to them the antibodies produce the more severe transfusional reactions. Nevertheless, there are many reactions that seemingly slip by for the clinical one in 4 hours later to the transfusion, period in which a narrower alertness is had in the patient. These antibodies (irregular antibodies) involved in many late reactions are capable of haemolyse red cells incompatible after 12, 24 or up to 72 hours of realized the transfusion, causing the death to the patient when the haemolysis is intravascular, without its manages to suspect that the reason was a reaction transfusional. This work had as general aim detect and identify the presence of irregular antibodies in samples tried of recipients and donors of the Bank of Blood of the Regional Hospital of Antofagasta, proving that the major number corresponded to the system Kell, with an incident of 25.42% of the Anti K O positive, 16.95% of the Anti K A positive.

En los últimos años, la medicina transfusional ha generado grandes avances en el área de la conservación y manejo de las fracciones sanguíneas, especialmente en la detección de icompatibidades entre donantes y receptores, utilizando antisueros monoclonales potentes y nuevos métodos que detectan anticuerpo concentraciones muy bajas. La mayoría de bancos de sangre se conforman, con proporcionar sangre compatible para los antígenos ABO y (D), porque frente a ellos los anticuerpos producen las reacciones transfusionales más severas. Sin embargo, hay muchas reacciones que aparentemente pasan inadvertidas para el clínico en las 4 horas posteriores a la transfusión, período en el que se tiene una vigilancia más estrecha en el paciente. Estos anticuerpos (anticuerpos irregulares) implicados en muchas reacciones tardías son capaces de hemolizar eritrocito es incompatibles después de 12, 24 o hasta 72 horas de realizada la transfusión, ocasionando la muerte al paciente cuando la hemólisis es intravascular, sin que se llegue a sospechar que la causa fue una reacción transfusional. Este trabajo tuvo como objetivo general detectar e identificar la presencia de anticuerpos irregulares en muestras procesadas de receptores y donantes del Banco de Sangre del Hospital Regional de Antofagasta, resultando que el mayor número correspondió al sistema Kell, con una incidencia de 25,42% del Anti K O positivo, 16,95% del Anti K A positivo.

Freqüência de anticorpos irregulares em politransfundidos no Hemocentro Regional de Uberaba-MG, de 1997 a 2005 / Frequency of irregular antibodies in multiple-transfused patients at the Regional Blood Bank of Uberaba, from 1997 to 2005

A fenotipagem eritrocitária pré-transfusional é um importante procedimento para aumentar a segurança das transfusões sangüíneas, sendo realizada rotineiramente no Hemocentro Regional de Uberaba-MG (HRU) desde 1996. O presente trabalho tem como objetivo geral avaliar a freqüência de anticorpos antieritrocitários irregulares em politransfundidos, de 1997 a 2005. Através de estudo retrospectivo foram levantados dados no arquivo do HRU de todos os pacientes aloimunizados, realizou-se análise estatística descritiva e comparam-se as proporções pelo teste "Z". Dos 23.220 transfundidos no período, com média de 5,7 transfusões por paciente, observou-se a ocorrência de aloimunização em 173 (0,75 por cento). Os sistemas Rh e Kell juntos tiveram freqüência superior a 70 por cento. A proporção do anti-D foi significativamente maior nas mulheres (p<0,05) e não houve diferença no sistema Rh entre brancos e não-brancos. Quanto à faixa etária, 70 por cento tinham mais de 30 anos. Dos 73 pacientes que tiveram a doença de base registrada, 39,73 por cento eram portadores de anemias agudas, 31,51 por cento de anemias crônicas e 28,77 por cento de doenças oncológicas ou onco-hematológicas. Aproximadamente 70 por cento dos anticorpos foram identificados até a décima transfusão. A baixa ocorrência da aloimunização no HRU reforça a importância da fenotipagem eritrocitária para todos os pacientes dependentes de transfusões crônicas, bem como da sua implantação na rotina de todos os serviços de hemoterapia.

Testing of the pre-transfusional blood phenotype, which has been carried out at the Regional Blood Bank in Uberaba since 1996, is an important procedure to improve safety of blood transfusions. This study aims to describe the frequency of irregular red blood cell antibodies in multiple-transfused patients from 1997 to 2005. In a retrospective study, data from all alloimmunized patients were collected from the blood bank files. Descriptive statistical analysis was performed and a comparison of proportions was made using the Z test. Alloimmunization was observed in 173 (0.75 percent) of the 23,220 transfused patients, with an average of 5.7 transfusions per patient. The frequency of the Rh and Kell systems jointly was over 70 percent. The proportion of anti-D was significantly higher in women (p<0.05) and no difference was noted in the Rh system between Caucasians and non-Caucasians. Seventy percent (70 percent) of the patients were over 30 years of age. Out of the 73 patients with registered diseases, 39.73 percent had acute anemias, 31.51 percent chronic anemias and 28.77 percent oncological or onco-hematologic diseases. Approximately 70 percent of antibodies were discovered before the 10th transfusion. The low frequency of alloimmunization observed at the Regional Blood Bank of Uberaba reinforces the importance of pre-transfusional blood phenotype screening for all multiple-transfused patients as well as its adoption as a common practice in all hemotherapy center.

Assessment of cowpea rhizobium diversity in Cerrado areas of northeastern Brazil

Com o objetivo de contribuir com a otimização do processo de fixação biológica de nitrogênio (FBN) na cultura do caupi (Vigna unguiculata (L) Walp) no Cerrado do nordeste brasileiro, a diversidade de isolados de rizóbio obtidos em oito áreas de Cerrado com rotação de cultura bianual com soja, arroz e caupi. Foram realizadas caracterizações morfológicas (produção de muco e morfologia das colônias), genotípicas baseadas em ARDRA do 16S rDNA e resistência a antibióticos. Os resultados da caracterização morfológica mostraram uma correlação inversamente proporcional (p < 0,05) do índice de diversidade de Shannon-Waver com o número de cultivos de leguminosas (caupi e soja). Os dados de ARDRA mostraram que no Cerrado nativo somente foram observados isolados de Bradyrhizobium elkanii, corroborando com dados da literatura. Nas áreas onde haviam sido cultivadas leguminosas ocorreram dois fatos distintos; onde somente cultivou-se soja houve maior proporção de B. japonicum e onde cultivou-se soja e caupi, ocorreu maior proporção de B. elkanii. A análise de resistência a antibióticos mostrou cinco diferentes perfis de resistência. Maior resistência de Bradyrhizobium spp. foi encontrada em áreas cultivadas há mais tempo, e menor na área nativa e/ou áreas com poucos cultivos. De forma geral, pode-se observar uma relação inversa entre a diversidade de rizóbios e a resistência a antibióticos. Como a menor diversidade foi observada em áreas com maior número de cultivos de leguminosas, sugere-se que a presença da leguminosa pode favorecer condições ecológicas específicas, nas quais determinados grupos de rizóbios adquirem características competitivas importantes para seu estabelecimento.

Variable kappa gene usage in swine antibodies

The kappa light chain locus of swine has been mapped to chromosome 3q12-q14 but at this time, there is not enough information comprising the variable region genes or their transcripts. Here we report the sequences of five transcripts of swine kappa light chain variable region obtained from the spleen of two adult Yorkshire pigs. The lengths of the deduced sequences of these transcripts were variable (between 107 to 112 amino acids). Comparisons of the nucleotide sequences of their variable regions with other species like human and murine VL genes shows a high degree of identity, indicating the use of at least two different families of variable light genes. The contribution of these genes to the generation of variability in swine light chain variable genes as well as their therapeutic use in humans is discussed. An interesting possibility would be the development of an antiretroviral vaccine, useful to protect against a potential risk of infections due to xenotransplantation (au)

Anticuerpos y receptores de células B / Antibodies and B cell receptors

Las inmunoglobulinas o anticuerpos son glicoproteínas que se encuentran en la superficie de los linfocitos B y son secretadas por las células plasmáticas, linfocitos B terminalmente diferenciados, en respuesta a un antígeno y, como tal, representan la inmunidad humoral de los vertebrados. Existen 5 formas o isotipos principales: IgG, IgM, IgA, IgD e IgE. Las Igs presentan una estructura básica que posee dos cadenas pesadas (H) idénticas y dos cadenas livianas (L) idénticas, unidas entre sí por puentes disulfuro e interacciones no covalentes. Ambos tipos de cadenas presentan un patrón estructural que consiste de segmentos o dominios de 110 aminoácidos. El análisis de su secuencia de aminoácidos revela la existencia de un dominio variable (V) hacia el extremo aminoterminal y varios dominios constantes (C) hacia el extremo carboxilo terminal. Las cadenas pesadas también poseen un dominio variable (VL) y uno constante (CL). Las cadenas pesadas también poseen un dominio variable (VH) pero tienen 3 ó 4 dominios constantes (CH). Los dominios variables de mabas cadenas contienen zonas de alta variabilidad no contiguas en la secuencia de aminoácidos, son las denominadas regiones hipervariables o CRD (determinantes de complementariedad) y son las principales responsables de la diversidad de los anticuerpos...

Investigación de anticuerpos irregulares en hemoterapia / Irregular antibodies investigation in hemotherapy

Se estudió la presencia de anticuerpos irregulares en 8141 pacientes encontrándose que el más frecuente corresponde al anti-E del sistema Rh-Hr. Los grupos con mayor exposición y frecuencia a transfusiones presentaron porcentajes mayores.