Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted.

The clinical significance of ABO blood group is evident and universally accepted with regards to blood transfusion and pregnancy; however, the importance of ABO blood group as it relates to other diseases or disorders and overall mortality is not fully understood by the scientific community. Many studies have suggested associations between blood groups and disease, but consensus has not been reached regarding overall survival or longevity. This epidemiological, retrospective review of ABO blood group and age at the time of death in a hospitalized population in the Southeastern United States is the first multi-site study to examine this relationship. The study population was 56% male, 63.4% White, 31.0% Black and 2.1% Hispanic. Over half (61.1%) of the population had been transfused with red blood cells within one year of death. Overall, group O (46.6%) was the most prevalent ABO blood group, followed by group A (36.8%), Group B (12.9%) and group AB (3.7%). The population exhibited differences in the frequencies of ABO blood groups across the races, with the Hispanic population having the highest prevalence of group O (71.2%) and the Black and Asian populations having higher frequencies of group B (22.2% and 23.1% respectively) when compared to the overall population distribution. Lifespan ranged from 0 to 110 with a mean age at death of 58.7 years. While some differences in the mean age at death were noted across ABO blood groups, the main effect of ABO blood group on lifespan did not reach statistical significance when controlling for race, gender and history of red blood cell transfusion. These results contradict other studies that found an association between a particular ABO blood group and lifespan. Future work should consider including cause of death or primary disease as potential confounders and targeting expanded populations over a wider geographic area to increase generalizability and racial diversity.

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.

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.

Antibody-mediated rejection is central to ABO incompatible transplantation as well as to xenotransplantation. The xenoantigen alpha-Gal has a highly analogous carbohydrate structure to the human blood group antigens, and both require memory B cell activation for antibody production. We hypothesize that B cells, reactive to the alpha-Gal xenoantigen and B blood group antigen, require the presence of fully activated T cells in order to survive and proliferate in vitro, contrary to the traditional theory that humoral response to carbohydrate antigens is a T cell-independent process. When we compared the capacity of B cells to proliferate, we observed that activated T cells were necessary for B cell proliferation even in the presence of carbohydrate-derived antigens. A relevant question was also to investigate the role of a specific class of T cells: the CD1d-restricted iNKT cells, in the activation of alpha-Gal and B blood group-reactive B cells. The iNKT cells have the specificity of being reactive to glycolipids and are capable of producing both T helper 1 and T helper 2 cytokine responses. We therefore wanted to determine the role of the iNKT cells as mediators of a T helper 2-type response when B cells were exposed to a glycolipid antigen expressing the alpha-Gal epitope or the human B blood group antigen. We observed that, if the interaction between B cells and iNKT cells is blocked, neither B cell proliferation nor antibody production occurs. These results suggest therefore the importance of the iNKT cell category of T helper cells in the response to alpha-Gal and ABO-blood group glycolipids.

Resumo: O sistema sangüíneo ABO (sABO) é o mais importante sistema na compatibilidade de grupos sangüíneos. Muitas pesquisas têm mostrado associações deste sistema com várias doenças infecciosas, inclusive a malária. Este estudo avaliou a associação entre os genótipos do sistema histo-sangüíneo ABO e a malária não grave causada pelo Plasmodium falciparum. A genotipagem dos grupos sangüíneos do sistema ABO foi feita de acordo com o protocolo de PCR/ RFLP, em amostras de indivíduos maláricos e não maláricos de áreas da Amazônia brasileira. O genótipo homozigoto ABO*O01O01 foi prevalente tanto nos maláricos quanto nos doadores de sangue. O genótipo ABO*AB representou cerca de 3% da população infectada e 5% da não infectada. Não foram verificadas diferenças estatisticamente significantes na comparação das freqüências alélicas e genotípicas do sABO entre pacientes e grupo controle, mesmo quando foram analisados apenas indivíduos com infecções puras de P. falciparum. A freqüência do sABO na Amazônia brasileira pode estar relacionada com a baixa freqüência de malária grave pelo P. falciparum. Portanto, os genótipos encontrados no sistema ABO dos indivíduos maláricos e não maláricos pode promover relevantes informações, para o entendimento da epidemiologia da malária grave por P. falciparum na Amazônia brasileira. / Abstract: The ABO blood system (sABO) is the most important system on the blood groups compatibility. Several studies have shown its associations with various infectious diseases, including malaria. This study evaluated the association between the ABO histo-blood genotypes and non-severe malaria caused by Plasmodium falciparum. PCR/RFLP protocol had be used for both ABO blood group system genotyping in malaria suffering individuals and blood donors, from malaria areas of the Brazilian Amazon. The homozygous genotype ABO*O01O01 was prevalent in both malaria and the blood donors. The genotype ABO*AB represented about 3% of the infected population and 5% of non-infected. No statistically significant differences were observed in sABO genotypic and allelic frequencies of patients and the control group, even when individuals were analyzed only with pure infection of P. falciparum. The frequency of sABO in the Brazilian Amazon may be related to the low frequency of non-severe malaria P. falciparum. Therefore, the genotypes found in the ABO blood system in malaric and non-malaric individuals can promote relevant information for the understanding of the severe malaria by P. falciparum epidemiology in the Brazilian Amazon. Keywords: Malaria; ABO blood group system; Plasmodium falciparum. / Orientador: Ricardo Luiz Dantas Machado / Coorientador: Luiz Carlos de Mattos / Banca: Carlos Eugênio Cavasini / Banca: Irineu Luiz Maia / Mestre