Malaria has exerted a major selective pressure for red blood cell (RBC) polymorphisms that confer protection to severe disease. There is a predominance of blood type O in malaria endemic regions, and several lines of evidence suggest that the outcome of Plasmodium falciparum infection may be influenced by ABO blood type antigens. Based on observations that enhanced phagocytosis of infected polymorphic RBCs is associated with protection to malaria in other red cell disorders, we hypothesized that infected type O RBCs may be more efficiently cleared by the innate immune system than infected type A and B RBCs. The present work demonstrates human macrophages in vitro and murine monocytes in vivo phagocytosed P. falciparum infected O RBCs more avidly than infected A and B RBCs independent of macrophage donor blood type. This difference in clearance may confer relative resistance to severe malaria in individuals with blood type O.

Malaria has exerted a major selective pressure for red blood cell (RBC) polymorphisms that confer protection to severe disease. There is a predominance of blood type O in malaria endemic regions, and several lines of evidence suggest that the outcome of Plasmodium falciparum infection may be influenced by ABO blood type antigens. Based on observations that enhanced phagocytosis of infected polymorphic RBCs is associated with protection to malaria in other red cell disorders, we hypothesized that infected type O RBCs may be more efficiently cleared by the innate immune system than infected type A and B RBCs. The present work demonstrates human macrophages in vitro and murine monocytes in vivo phagocytosed P. falciparum infected O RBCs more avidly than infected A and B RBCs independent of macrophage donor blood type. This difference in clearance may confer relative resistance to severe malaria in individuals with blood type O.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

Thesis--Copenhagen. / Includes bibliographical references.

A principal hipótese para explicar o polimorfismo do sistema dos grupos sanguíneos ABH humana é a co-evolução com patógenos. Através de modelagem matemática já foi demonstrado que patógenos bacterianos que utilizam os glicanos ABH de superfície como receptores de adesão favorecem os fenótipos A e B enquanto os patógenos virais revestidos por estes glicanos favorecem o fenótipo nulo O que possui anticorpos naturais anti-A e anti-B. Limitações práticas têm impedido demonstrar até o presente momento como a co-evolução entre patógenos e hospedeiro atua sobre os anticorpos naturais contra os glicanos ABH. O presente trabalho demonstra pela primeira vez em uma grande população de doadores de sangue (N: 271.410) que a assimetria dos grupos sanguíneos do sistema ABO e seus respectivos anticorpos associados à reação cruzada do anti- Galα1-3Gal pode explicar a freqüência significativamente maior de infecção por HIV em doadores de sangue do grupo sanguíneo B. A reação cruzada anti-B causada pela maior capacidade de imuno-reconhecimento do anticorpo anti- Galα1-3Gal presente nos grupos sanguíneos A e O comparada ao encontrado no grupo B pode também justificar o predomínio do alelo A sobre o alelo B na maioria das populações humanas. / Co evolution with pathogens is the principal hypothesis to explain the polymorphism of the ABO blood group system. Mathematic models demonstrate that bacterial pathogens exploring ABH surface glycans as attachment receptors impose selective pressure in favour of A and B phenotypes while glycan covered viruses favor act in favour of the O phenotype who’s serum contains natural occurring anti-A and anti-B antibodies. Natural antibodies against ABH glycans acting in co evolution between hosts and pathogens has by practical limitations not been demonstrated until present. The present study demonstrated for the first time in a great population of blood donors (N: 271.410) that the asymmetry of ABO blood group system antigens and antibodies in associated with cross reacting anti- Galα1-3Gal antibodies can explain the higher frequency of HIV infection in blood donors of group B and also the higher frequency of the A allele compared to the B allele in most human populations.

Cholera is an acute diarrheal illness burdening several developing countries caused by toxigenic Vibrio cholerae, where endemics maintain a seasonal pattern and occur more than once a year. Cholera is endemic in certain regions of Africa and South America, and southern Asia, where outbreaks are associated with poor hygiene and sanitary conditions. Every year, 3–5 million cases of cholera are diagnosed, and it causes more than 100,000 deaths worldwide. Cholera toxin is secreted by the V. cholerae bacteria and causes extreme secretory diarrhea, most commonly in poor hygiene environment. Watery diarrhea, vomiting, and abdominal cramps characterize the illness and approximately 5–10% of patients die of severe fluid loss if left untreated. The structure and function of the cholera toxin, its subunits, receptor, and impact on hyperactivation of cyclic adenosine monophosphate (cAMP) were sufficiently described in the 1970s. These findings fit with epidemiologic observations, which determined that the cholera toxin must first enter intestinal cells by binding to monosialoganglioside (GM1) on the host’s epithelial surface. The correlation between increase risk of V. cholerae infection and individuals with a particular ABO blood group type is unclear because of the scarce information and few studies conducted. Thus, this study reviews published research articles to better understanding the association between the blood group O and susceptibility to developing severe cholera symptoms. Several large studies have recorded an association between ABO blood groups and different infectious agents). Anthropological surveys suggest that the racial and geographic distribution of human blood types reflects tendencies towards specific erythrocyte types susceptible to infectious disease, such as cholera and malaria. Experimentally, the V. cholerae toxin has been extensively used as an experimental adjuvant, and its association with ABO groups is of practical importance for the development of an oral cholera vaccination. The results of previous studies provided strong evidence that individuals with blood type O are more vulnerable than other persons to severe cholera symptoms, even though the biologic basis for this association remains unknown.

A principal hipótese para explicar o polimorfismo do sistema dos grupos sanguíneos ABH humana é a co-evolução com patógenos. Através de modelagem matemática já foi demonstrado que patógenos bacterianos que utilizam os glicanos ABH de superfície como receptores de adesão favorecem os fenótipos A e B enquanto os patógenos virais revestidos por estes glicanos favorecem o fenótipo nulo O que possui anticorpos naturais anti-A e anti-B. Limitações práticas têm impedido demonstrar até o presente momento como a co-evolução entre patógenos e hospedeiro atua sobre os anticorpos naturais contra os glicanos ABH. O presente trabalho demonstra pela primeira vez em uma grande população de doadores de sangue (N: 271.410) que a assimetria dos grupos sanguíneos do sistema ABO e seus respectivos anticorpos associados à reação cruzada do anti- Galα1-3Gal pode explicar a freqüência significativamente maior de infecção por HIV em doadores de sangue do grupo sanguíneo B. A reação cruzada anti-B causada pela maior capacidade de imuno-reconhecimento do anticorpo anti- Galα1-3Gal presente nos grupos sanguíneos A e O comparada ao encontrado no grupo B pode também justificar o predomínio do alelo A sobre o alelo B na maioria das populações humanas. / Co evolution with pathogens is the principal hypothesis to explain the polymorphism of the ABO blood group system. Mathematic models demonstrate that bacterial pathogens exploring ABH surface glycans as attachment receptors impose selective pressure in favour of A and B phenotypes while glycan covered viruses favor act in favour of the O phenotype who’s serum contains natural occurring anti-A and anti-B antibodies. Natural antibodies against ABH glycans acting in co evolution between hosts and pathogens has by practical limitations not been demonstrated until present. The present study demonstrated for the first time in a great population of blood donors (N: 271.410) that the asymmetry of ABO blood group system antigens and antibodies in associated with cross reacting anti- Galα1-3Gal antibodies can explain the higher frequency of HIV infection in blood donors of group B and also the higher frequency of the A allele compared to the B allele in most human populations.

A principal hipótese para explicar o polimorfismo do sistema dos grupos sanguíneos ABH humana é a co-evolução com patógenos. Através de modelagem matemática já foi demonstrado que patógenos bacterianos que utilizam os glicanos ABH de superfície como receptores de adesão favorecem os fenótipos A e B enquanto os patógenos virais revestidos por estes glicanos favorecem o fenótipo nulo O que possui anticorpos naturais anti-A e anti-B. Limitações práticas têm impedido demonstrar até o presente momento como a co-evolução entre patógenos e hospedeiro atua sobre os anticorpos naturais contra os glicanos ABH. O presente trabalho demonstra pela primeira vez em uma grande população de doadores de sangue (N: 271.410) que a assimetria dos grupos sanguíneos do sistema ABO e seus respectivos anticorpos associados à reação cruzada do anti- Galα1-3Gal pode explicar a freqüência significativamente maior de infecção por HIV em doadores de sangue do grupo sanguíneo B. A reação cruzada anti-B causada pela maior capacidade de imuno-reconhecimento do anticorpo anti- Galα1-3Gal presente nos grupos sanguíneos A e O comparada ao encontrado no grupo B pode também justificar o predomínio do alelo A sobre o alelo B na maioria das populações humanas. / Co evolution with pathogens is the principal hypothesis to explain the polymorphism of the ABO blood group system. Mathematic models demonstrate that bacterial pathogens exploring ABH surface glycans as attachment receptors impose selective pressure in favour of A and B phenotypes while glycan covered viruses favor act in favour of the O phenotype who’s serum contains natural occurring anti-A and anti-B antibodies. Natural antibodies against ABH glycans acting in co evolution between hosts and pathogens has by practical limitations not been demonstrated until present. The present study demonstrated for the first time in a great population of blood donors (N: 271.410) that the asymmetry of ABO blood group system antigens and antibodies in associated with cross reacting anti- Galα1-3Gal antibodies can explain the higher frequency of HIV infection in blood donors of group B and also the higher frequency of the A allele compared to the B allele in most human populations.

This research investigates the role of ABO blood type of erythrocytes in their dielectrophoretic response. The dielectrophoresis of erythrocytes of positive ABO blood types was studied at 5 V (peak to peak) and 1 MHz frequency AC field. The study revealed that the ABO blood type had an influence on the dielectrophoretic motion of the erythrocytes, particularly separating AB+ and O+ blood types. This is of particular significance since AB+ is a universal acceptor and O+ is a universal donor for blood transfusion purposes. The influence of field parameters, namely field strength and frequency of the AC field, was also studied for erythrocytes of positive ABO blood types. This research revealed that erythrocytes of each blood type respond differently at various frequencies and field strengths.

Submitted by Fabíola Silva (fabiola.silva@famerp.br) on 2018-01-09T11:15:21Z No. of bitstreams: 1 marcospaulomiola_dissert.pdf: 10829870 bytes, checksum: 279acd690e09b25b71e67463ae29eb6b (MD5) / Made available in DSpace on 2018-01-09T11:15:21Z (GMT). No. of bitstreams: 1 marcospaulomiola_dissert.pdf: 10829870 bytes, checksum: 279acd690e09b25b71e67463ae29eb6b (MD5) Previous issue date: 2017-03-13 / Introduction. ABO histo-blood group system is the most important transfusional system and the identification of its phenotypes is often performed by means of direct and reverse typing, which must always present concordant results. However, some genetic factors such as natural chimerisms and point mutations in the ABO gene may affect the expression of the antigens and antibodies of this system, contributing to the discrepancy in the phenotyping, requiring investigations to define the correct phenotype of receptors and blood donors. Objectives. The main objective of this study was to investigate the variations in the expression of the antigens of the ABO histo-blood group system. Its specific objectives were: 1. Selection of recipients and blood donors that presented discrepancies between the results of the direct and reverse phenotyping of the ABO histo-blood group system; 2. Investigation, using serological and molecular methods, of the causes of phenotypic changes and discrepancies between the results of direct and reverse phenotypes in the ABO histo-blood group system in the recipients and donors of blood. Material and Methods. Samples of recipients (n = 2) and blood donors (n = 7) presenting discrepancies between the direct and reverse phenotyping were selected. Phenotyping were performed using conventional and modified hemagglutination methods in tubes and gel columns with commercial antisera and lectins. Molecular investigations were performed using PCR-RFLP method and sequencing of exons 6 and 7 of the ABO gene and exon 2 of the FUT2 gene. Results. Four cases with poor expression of antigen A and absence of expected antibody, observed in hemagglutination, were identified as A2B, Ael and Aw. Four cases without antigenic alteration but carrying an irregular antibody anti-A1 or absence of expected antibody were characterized as AB, A1 and O and presented common ABO alleles. A case of non-dizygotic twins, phenotyped as AB and with double red blood cell population was characterized as hematopoietic chimera after extensive family analysis. The DNA extracted from buccal swab revealed the ABO (A101/B101) and FUT2 (SE*25.01.01/SE*25.01.01) genotypes in the male twin and the ABO (O01/O02) and FUT2 (SE*01.04.01/SE*01.06.03) genotypes in the female twin. Sequences of two new ABO (ABO*Aw.38; KT906366.1) and FUT2 (SE*01.06.03; KX550421) allele sequences were deposited on GenBank. Conclusions. Our results demonstrate that the use of serum and salivary serological assays combined with molecular methods are good tools to solving discrepancies between the direct and reverse phenotyping of the ABO histo-blood group system as well as elucidate cases of twin chimerism in humans, with a double population of red blood cells. In addition, they contribute to the identification of new alleles of the ABO and FUT2 genes. / Introdução. O sistema histo-sanguíneo ABO é o de maior importância transfusional e a identificação de seus fenótipos é frequentemente realizada por meios das tipagens direta e reversa as quais sempre devem apresentar resultados concordantes. Entretanto, alguns fatores genéticos como quimerismos naturais e mutações pontuais no gene ABO, podem afetar a expressão dos antígenos e anticorpos deste sistema, contribuindo com a discrepância nas fenotipagens, requerendo investigações para se definir o correto fenótipo de receptores e doadores de sangue. Objetivos. O objetivo geral deste estudo foi investigar as variações na expressão dos antígenos do sistema histo-sanguíneo ABO. Seus objetivos específicos compreenderam: 1. Seleção de receptores e doadores de sangue que apresentaram discrepâncias entre os resultados das fenotipagens direta e reversa do sistema histo-sanguíneo ABO; 2. Investigação, com o uso de métodos sorológicos e moleculares, das causas das alterações fenotípicas e discrepâncias entre os resultados das fenotipagens direta e reversa no sistema histo-sanguíneo ABO nos receptores e doadores de sangue. Material e Método. Foram selecionadas amostras de receptores (n=2) e doadores (n=7) de sangue com discrepâncias entre as fenotipagens direta e reversa. As fenotipagens foram realizadas com o uso dos métodos de hemaglutinação convencional e modificada, em tubos e colunas de gel, com antissoros comerciais e lectinas. As investigações moleculares foram realizadas com o uso dos métodos PCR-RFLP e sequenciamento dos exons 6 e 7 do gene ABO e do exon 2 do gene FUT2. Resultados: Quatro casos com fraca expressão do antígeno A e ausência do anticorpo esperado, observados na hemaglutinação, foram identificados como A2B, Ael e Aw. Quatro casos sem alteração antigênica, mas com presença de anticorpo irregular ou ausência do anticorpo esperado, foram caracterizados como AB, A1 e O e apresentaram alelos comuns. Um caso de gêmeos não dizigóticos, fenotipados como AB e com dupla população de hemácias foi caracterizado como quimera hematopoiética, após extensa análise familiar. O DNA extraído de swab bucal revelou os genótipos ABO (A101/B101) e FUT2 (SE*25.01.01/SE*25.01.01) no gêmeo masculino e os genótipos ABO (O01/O02) e FUT2 (SE*01.04.01/SE*01.06.03) no gêmeo feminino. As sequências de dois novos alelos dos genes ABO (ABO*Aw.38; KT906366.1) e FUT2 (SE*01.06.03; KX550421) foram depositadas no GenBank. Conclusões: Nossos resultados demonstram que o uso de análises sorológicas eritrocitárias e salivares combinadas a métodos moleculares são fundamentais na resolução de discrepâncias entre as fenotipagens direta e reversa do sistema histo-sanguíneo ABO bem como no esclarecimento de casos de quimerismo gemelar em humanos, contendo dupla população de hemácias. Além disso, contribuem para a identificação de novos alelos dos genes ABO e FUT2.