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Genetic of the ABO blood system and its link with the immune system



In the book "Eat Right For Your Type" the author Peter J. D'Adamo writes that the O blood type was the first blood type to appear in humans and affirms that the blood groups are the key to the immune system. Some recent phylogenetic network studies in humans and non-human primates implies that the A gene represents an ancient form of the ABO genes. Relationships between blood groups and infectious and noninfectious diseases and immunodeficiency abnormalities have also been reported in the literature. As D'Adamo's propositions seem to be in opposition with the current knowledge, we present in this paper some comments about the genetics and the evolution of the ABO blood group genes and some links between this blood system and the functioning of the immune system.
Rev. bras. hematol. hemoter. 2004;26 (1):60-63 Artigo Educacional
Artigo educacional / Educational article
Genetic of the ABO blood system and its link with the immune system
A genética do sistema ABO e sua relação com o sistema imune
Luiz C. de Mattos
Haroldo W. Moreira
Molecular Biology Department, Faculty of Medicine of São José do Rio Preto, SP.
Clinical Analysis Department, Faculty of Pharmaceutical Sciences, UNESP, Araraquara, SP.
Financial support: BAP Famerp (case 06336/00).
Correspondence to: Molecular Biology Department
Faculty of Medicine of São José do Rio Preto
Avenida Brigadeiro Faria Lima, 5416
15090-000 – São José do Rio Preto-SP – Brasil
Tel: 55 17 210-5700 / Fax: 55 17 227-6201 – e-mail:
In the book “Eat Right For Your Type” the author Peter J. D’Adamo writes that
the O blood type was the first blood type to appear in humans and affirms that
the blood groups are the key to the immune system. Some recent phylogenetic
network studies in humans and non-human primates implies that the A gene
represents an ancient form of the ABO genes. Relationships between blood groups
and infectious and noninfectious diseases and immunodeficiency abnormalities
have also been reported in the literature. As D’Adamo’s propositions seem to be
in opposition with the current knowledge, we present in this paper some comments
about the genetics and the evolution of the ABO blood group genes and some
links between this blood system and the functioning of the immune system. Rev.
bras. hematol. hemoter. 2004;26 (1):60-63.
Key words: ABO system; genetics; polymorphism; immune system
In 1997 the American naturopathic physician
Peter J. D’Adamo wrote a book entitled “Eat Right For
Your Type”
in which he presents a dietary program
based on the ABO blood types.
Also, the author explo-
res some aspects of the genetics and the evolution of
this blood system and affirms that the blood groups are
the key to the functioning of the immune system.
It is
not our intention to discuss here the supposed links
among ABO blood types to any dietary program.
Instead, we wish to present some comments about two
questions related to the genetics and evolution of the
ABO blood group genes and the links between this blood
system and the immune system according to current
knowledge, which are different to D’Adamo’s
Was the O type the first blood type to appear in
Dr. D’ Adamo writes that the O blood type of the
ABO blood system was the first human blood type. The
ABO blood group system is a genetic trait determined by
genes occupying the ABO locus on chromosome 9
(9q34.1). This blood system is characterized by the
expression of two carbohydrate antigens (A and B)
expressed on the red blood cell membrane and in many
other tissues and two plasmatic antibodies (anti-A and
anti-B) that appear after birth. The synthesis of these
antigens is controlled by specific glycosyltransferases. The
A and B genes code to functional glycosyltransferases
capable of converting the H antigen precursor into A or
B antigens. The O gene codes to an anomalous
glycosyltransferase that is incapable of modifying the H
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Artigo Educacional Rev. bras. hematol. hemoter. 2004;26 (1):60-63
antigen. Independently, the synthesis of the red blood
cell H antigen is controlled by an a-2-L-fucosyltranferase
coded by the H gene (FUT-1) of the locus H located in
the chromosome 19 (19q13.3), from the precursor type 2
oligosaccharides (Galb1®4GluNAc). In individuals with
the secretor phenotype, the SE gene (FUT-2) codes to a
similar a-2-L-fucosyltransferase that is capable of
synthesizing the H antigen from the precursor of the type
1 oligosaccharide (Galb1®3GluNAc) in other tissues.
Therefore, the A, B, H and SE genes code to functional
glycosyltransferases but the O, h and se genes are
incapable of this.
In order to agree with the assertion that the O blood
type was the first human blood type to appear, it would
be necessary to admit that before humans, only the H
locus existed in non-human primates, but this does not
make any sense. Many papers were able to demonstrate
the presence of ABO antigens and the glycosyltransferases
responsible for the synthesis of the A antigen in tissues
and secretions collected from other non-human
Another possibility would be to accept that
the O gene evolved before the A and B genes in the ABO
locus. After constructing phylogenetic networks of human
and non-human ABO alleles, Saitou and Yamamoto
concluded that the A gene represents the ancestral form.
Thus, in the evolutionary sense, it is difficult to believe
that normal genes like A and B have evolved from
abnormal genes like O.
The three most common O genes identified in
different populations are O
, O
(variant) and O
Compared to the ancestral form, the O
and O
have a deletion of a G base in exon 6 (guanine in position
261) and show additional nucleotide differences.
gene does not have the G deletion but has a substitution
(G802A) in exon 7, which appears to abolish its
Although the O blood type is common in all
populations around the world,
there is no evidence that
the O gene represents the ancestral gene at the ABO locus.
Nor is it reasonable to suppose that a defective gene would
arise spontaneously and then evolve into normal genes.
Is the ABO blood system the key of the immune
Dr. D’Adamo also asserts that the ABO blood group
system is the key to immune function. There are
interesting interactions among blood types and the
immune system. The blood types are characterized by
polymorphic antigens expressed in the red blood cell outer
membranes and in other tissues, similar to ABO.
to immunogenicity, blood group antigens induce immune
responses following incompatible transfusions, during
pregnancy or after organ transplantation. Environmental
stimuli also contribute to the production of so-called “na-
tural antibodies”. Thus, a person can produce regular
and irregular antibodies specific to blood group antigens.
This feature represents a link between the blood groups
and immune function but is not the key to the immune
The biological functions of blood group
polymorphisms are not completely understood but many
blood group antigens act as important molecules in the
cell-cell recognition involved in early embryonic tissue
differentiation and probably as a self declaration
mechanism in somatic cell communities.
There is also abundant evidence that blood groups
play a role in the susceptibility or resistance to various
infectious and non-infectious diseases.
One of the
arguments used to reinforce the role of these molecules
is the higher expression of the ABO carbohydrates in
secretions and tissues that have contact with the
environment such as in the skin and in mucous
membranes of respiratory and gastrointestinal tracts.
infectious processes are related to the attachment of
microbes to molecules expressed in host cells, probably
the ABO (and its associated genetic systems, Secretor
and Lewis) carbohydrate antigens evolved to create a
polymorphic profile in the mucous membrane. This is
important to alter potential receptors of bacteria, viruses,
Therefore, diversity of these antigens can be related
to the susceptibility or resistance to infectious diseases
and this feature also represents a functional relationship
between blood groups and the immune function. Experi-
mental evidence demonstrated the importance of the H
antigen, expressed in gastric mucous membrane, to the
attachment of Helicobacter pylori bacillus.
epidemiological studies observed that the O blood group
is more common among individuals infected by this
Other papers also suggested that similar
mechanisms are implied in susceptibility of the Lewis
negative phenotype [Le(a-b-)] to the uro-pathogenic
Escherichia coli strain.
Despite these facts it is
difficult to believe that blood types represent the key to
the immune system. It is worthwhile remembering that a
small number of blood group systems express their
antigens in tissues other than hematopoietic tissue.
Rare null phenotypes were described in many blood
systems, some of which are associated with diseases, but
this is not a general rule. For example, carriers of McLeod
phenotype have a weak expression of Kell antigens and
do not express the Kx substance in their red blood cell
membrane. However, some phenotypes have an immune
dysfunction named X-linked chronic granulomatous
Carriers of Rh null syndrome, a hematological
disorder characterized by mild or moderate hemolytic ane-
mia, do not express Rh antigens in the red blood cell
membrane but this phenomenon is not related to immune
Besides there is no evidence of any immune
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Rev. bras. hematol. hemoter. 2004;26 (1):60-63 Artigo Educacional
dysfunction among carriers of the Bombay phenotype, a
rare phenotype in which the A, B and H antigens are
absent, but the anti-A, anti-B and anti-H are expressed.
The immune system is a biological system that
evolved to discriminate self from non-self using a complex
network of T and B lymphocytes, antigen presenting cells,
cytokines, antigen receptors, antibodies, MHC restriction
and other cellular and molecular interactions. They is
important due to their ability to protect us against
intracellular and extra-cellular pathogenic micro-
organisms through cellular and humoral immune
Although there are links between the immune
system and blood group phenotypes, antibodies are
produced by the cells of the immune system and not by
the blood type loci. It is possible to detect the A and B
antigens in red blood cells and in secretions of newborn
babies but they do not express anti-A and anti-B antibodies
until several months of age. Possibly the influence of
environmental stimuli resulting from similar
carbohydrates expressed in microorganisms contributes
to the production of natural antibodies.
It is also
worthwhile to note that in the ABO blood group system,
the only system in which “regular antibodies” can be
detected, the specificities of anti-A, anti-B and anti-A,B
are necessary, but not sufficient to protect the body against
the higher antigen diversity present in the environment
and for normal immune function. Of course, the blood
type antigens and their specific antibodies are part of but
certainly not the key to the immune system.
Concluding remarks
The A, B, H and precursor oligosaccharides in many
mammalian species, in humans and non-human primates
as well as the glycosyltransferases responsible for their
synthesis have been well characterized at the biochemical
and molecular levels. The resulting knowledge can help
not only in the definition of an appropriated model to
explain the evolution and the biological importance of
the ABO blood system related to diseases, but also to
repudiate any absurd speculation without scientific base.
Finally, the complexities of the blood types and their
relationship with the functional aspects of the immune
system deserve much additional study. In the meantime,
D’Adamo’s speculations about the evolution of the ABO
blood types and the blood groups as the key to the immune
system appear to be fundamentally flawed.
Peter J. D’Adamo, autor do livro “Eat Right For Your Type”,
escreve que o grupo O representa o primeiro tipo sangüíneo
que surgiu nos humanos e também afirma que os grupos
sangüíneos constituem as bases do sistema imune. Recentes
estudos filogenéticos realizados em primatas humanos e não
humanos estabeleceram que o gene A representa a forma an-
cestral dos genes que ocupam o locus ABO. Associações entre
os grupos sangüíneos ABO, doenças infecciosas, não infecci-
osas e imunodeficiências também foram relatadas. Diante das
proposições do autor, as quais se opõem às informações resul-
tantes de recentes estudos moleculares e filogenéticos, nossa
intenção é apresentar algumas reflexões sobre a genética e a
evolução dos genes do sistema ABO e as conexões deste siste-
ma com o sistema imune. Rev. bras. hematol. hemoter. 2004;26
Palavras-chave: Sistema ABO; genes ABO; sistema imune
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Editor e dois revisores externos.
Conflito de interesse: não declarado
Recebido: 15/08/2003
Aceito após modificações: 01/09/2004
Artigo Educacional.p65 07/05/2004, 14:2263
... The immune system can distinguish between self and non-self. 9 Many cytokines, other molecules, and cells interact with a complex network for the immune system to function efficiently. The relationship between the ABO blood group and an immune response is well-established. ...
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Objective: We investigated the prognostic and predictive effects of the ABO blood group system on patients receiving immune checkpoint inhibitors for advanced renal cell carcinoma (RCC). Material and Methods: In this retrospective observational study, the data on the patients with known ABO blood group, who were administered nivolumab for mRCC, were reviewed. The tumor response rates and survival were analyzed based on the ABO blood group. Results: A total of 89 patients were included in the study. The median age of the patients was 57 (range: 24-83 years) years, and 67% (n=60) of the patients were male. Moreover, 43%, 18%, 9%, and 30% of the patients had blood groups A, B, AB, and O, respectively. Our study had a median follow-up time of 11 months. Although the groups did not differ significantly in progression-free survival (PFS) and overall survival (OS) according to the blood groups, patients who had the B blood type survived longer. For patients with blood types A, B, AB, and O, the median PFS was 5.3 months, 8.4 months, 3.7 months, and 7.8 months, respectively (p=0.8), and the median OS was 14.5 months, 20.3 months, 12.0 months, and 16.5 months, respectively (p=0.8). Conclusion: Although the groups did not differ significantly according to the ABO blood group, the patients with the B blood group survived relatively longer. These results suggested that further studies with more patients should be conducted.
... ACE2, being the main receptor, binds to cells expressing blood group moieties most reported in the mucous membrane of the respiratory tract. Thus, blood group AB has the most contact and blood group O the least contact with SARS-CoV-2 (27,63). This is further demonstrated in this study, where patients with blood type O were less likely to present to hospital with critical COVID-19. ...
Full-text available
Introduction: Coronavirus disease 2019 (COVID-19) disease severity differs widely due to numerous factors including ABO gene-derived susceptibility or resistance. The objective of this study was to investigate the association of the ABO blood group and genetic variations of the ABO gene with COVID-19 severity in a heterogeneous hospital population sample from the United Arab Emirates, with the use of an epidemiological and candidate gene approach from a genome-wide association study (GWAS). Methods: In this cross-sectional study, a total of 646 participants who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were recruited from multiple hospitals and population-based (quarantine camps) recruitment sites from March 2020 to February 2021. The participants were divided into two groups based on the severity of COVID-19: noncritical ( n = 453) and critical [intensive care unit (ICU) patients] ( n = 193), as per the COVID-19 Reporting and Data System (CO-RADS) classification. The multivariate logistic regression analysis demonstrated the association of ABO blood type as well as circulating anti-A antibodies and anti-B antibodies as well as A and B antigens, in association with critical COVID-19 hospital presentation. A candidate gene analysis approach was conducted from a GWAS where we examined 240 single nucleotide polymorphisms (SNPs) (position in chr9 : 136125788-136150617) in the ABO gene, in association with critical COVID-19 hospital presentation. Results: Patients with blood group O [odds ratio (OR): 0.51 (0.33, 0.79); p = 0.003] were less likely to develop critical COVID-19 symptoms. Eight alleles have been identified to be associated with a protective effect of blood group O in ABO 3'untranslated region (UTR): rs199969472 ( p = 0.0052), rs34266669 ( p = 0.0052), rs76700116 ( p = 0.0052), rs7849280 ( p = 0.0052), rs34039247 ( p = 0.0104), rs10901251 ( p = 0.0165), rs9411475 ( p = 0.0377), and rs13291798 ( p = 0.0377). Conclusion: Our findings suggest that there are novel allelic variants that link genetic variants of the ABO gene and ABO blood groups contributing to the reduced risk of critical COVID-19 disease. This study is the first study to combine genetic and serological evidence of the involvement of the ABO blood groups and the ABO gene allelic associations with COVID-19 severity within the Middle Eastern population.
... Also, individuals with O blood type have a lower level of ACE unlike A blood type (91) and the positive relationship between ACE level with hypertension (one of the risk factor of COVID-19) (92) can justify the lower rate of COVID-19 among individuals with O blood type and higher rate of COVID-19 among individuals with A blood type. On the other hand, it has been shown that SARS-CoV-2 attaches to the carbohydrates that specify the ABO blood groups, which are extensively expressed in mucous membrane of respiratory tract; therefore, AB blood group has maximum connection and O blood group the minimum connection with the pathogen (22,93). Furthermore, a research conducted by Dai manifested A blood group antigens have more adhesion molecules that are attached on the vascular wall and they protect P-selectin and Intercellular Cell Adhesion Molecule 1 (ICAM-1) from cleavage which enhance inflammation and adhesion and consequently cause severe SARS-COV-2 infection (91). ...
Full-text available
The COVID-19 virus has caused many deaths of people worldwide since the pandemic began. However, no definitive treatment for this infection has been discovered so far. It has been shown that comorbidities such as diabetes, hypertension and cardiovascular diseases are associated with an increased risk of SARS-COV-2 infection. Interestingly, SARS-COV-2, like SARS-COV, uses the ACE2 gene to enter the host cell. Also, changes or imbalance in ACE2.ACE can affect SARS-COV-2 susceptibility, related outcomes and mortality. Regarding the crucial role of ACE2 protein in COVID-19 infection, the effect of different factors such as age, BMI, physical activity levels, nutritional status, altitude, as well as blood group was assessed on the level of this protein. Further, to our knowledge, no study has been conducted to examine factors that increase or decrease the risk of COVID-19 and its related severity and outcome in normal subjects emphasizing the pivotal role of ACE2. Therefore, the primary purpose of this study was to investigate the involved mechanisms of ACE2 protein and other risk factors causing infection in different situations and finally, to introduce a safe, accurate, and cost-effective approach to prevent SARS-COV-2 infection and hard clinical outcomes in normal subjects.
... This is reliable with research in Iraq and Iran (37,38), the carbohydrate antigens contributed tovulnerability to diseases infectious (39). Specially, the H antigen of group O blood uttered in the gastric mucous membrane is appropriate to the add-on of Helicobacter pylori (40, 41). ...
... Although the primary receptor for SARS-CoV-2 is ACE2 [31], like many pathogens that bind to specific terminal carbohydrates [32], SARS-CoV-2 binds to the carbohydrates that determine the ABO blood groups, which are extensively expressed in mucous membrane of respiratory tract [31,33]. Therefore, blood group AB has the most contact and blood group O the least with the pathogen [31]. ...
Full-text available
Introduction The relationship between ABO blood group and the incidence of COVID-19 infection and death has been investigated in several studies. The reported results were controversial, so the objective of the present study is to assess the relationship between different blood groups and the onset and mortality of COVID-19 infection using meta-analysis method. Methods We searched the databases using appropriate MeSH terms. We screened articles on the basis of titles, abstracts, and full texts, and the articles that met the inclusion criteria were selected. Quality assessment was done with the Newcastle-Ottawa Scale checklist. The estimated frequency of COVID-19 infection and death in terms of ABO blood group and the overall estimate of the odd ratio between blood group with COVID-19 infection and death was done with 95% confidence interval. Results The pooled frequency of blood groups A, B, O, and AB among COVID-19 infected individuals was estimated as 36.22%, 24.99%, 29.67%, and 9.29% respectively. The frequency of blood groups A, B, O, and AB among the dead cases due to COVID-19 infection was estimated as 40%, 23%, 29%, and 8% respectively. The odd ratio of COVID-19 infection for blood group A versus the other blood groups was estimated 1.16 (CI 95%: 1.02-1.33). The corresponding figures for blood groups O and AB versus other blood groups were estimated as 0.73 (CI 95%: 0.60-0.88) and 1.25(CI 95%: 0.84-1.86) respectively. Conclusion This meta-analysis showed that individuals with blood group A are at higher risk for COVID-19 infection while those with blood group O are at lower risk. Although the odds ratio of death for AB blood group was non-significant, it was considerable.
... 19,20 It can be explained that this is because of the carbohydrate antigens that contributed to the susceptibility or resistance to infectious diseases. 21 Especially, the H antigen of blood group O expressed in the gastric mucous membrane is suitable to the attachment of Helicobacter pylori bacillus which is identified to be the major cause of PUD. 16,22 Despite the fact that PUD had a higher prevalence among blood group O patients, there was no significant association between ABO blood group distribution and PUD in the current study. ...
Full-text available
Background: Studies have shown that ABO blood group antigens are associated with peptic ulcer disease (PUD). There are limited sources regarding the association of blood groups with PUD patients in Ethiopia. The aim of this study was to assess the association between ABO blood group distribution, non-steroidal anti-inflammatory drugs (NSAIDs), smoking, alcohol, coffee, and PUD at Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia. Methods: A cross-sectional study was undertaken, and a total of 63 endoscopically confirmed PUD patients and 63 healthy controls were screened for ABO blood grouping using the standard slide agglutination reaction. Stool antigens were checked to determine Helicobacter pylori status of PUD patients. Chi-square and logistic regression were used for statistical analysis. Results: The ABO blood group distribution of PUD patients was 19.04% (12/63), 19.04% (12/63), 11.11% (7/63), 50.79% (32/63) for blood group A, B, AB, and O, respectively, while among control groups it was 25.39% (16/63), 23.80% (15/63), 12.69% (8/63), and 38.09% (24/63) for blood group A, B, AB, and O, respectively. 34.1% (22/63) of PUD patients had gastric ulcer and 65.9% (41/63) had duodenal ulcer. There was statistically a significant association between sex (p=0.001), use of NSAIDs (p=0.001), smoking cigarette (p=0.014), alcohol consumption (p=0.028), and PUD. Conclusion: Although PUD trended as more prevalent among patients with blood group O than other blood group types their association was not statistically significant.
... The blood group antigens are present not only on the red blood cell surfaces but also widely distributed throughout the body tissues and secretions. [1][2][3] The basic precursor substance of A and B antigens is an oligosaccharide which is converted by an enzyme L-fucosyl transferase (a product of H gene) to H substance by addition of sugar L-fucose to terminal D-galactose of the precursor substance. 4,5 Cancer is one of the leading causes of morbidity and mortality worldwide. ...
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Background: Numerous studies have documented the association of the ABO blood groups with the occurrence of cancers. Aim was to find out an association of ABO blood groups and various cancers in the North Eastern region of India.Methods: The study was a retrospective observational study that included 1000 cases and 1000 controls. The data included the ABO blood typing of the selected cancer sites which were head and neck, esophagus, stomach, breast, cervix, and ovary. Patients who attended blood bank of regional cancer center with requisition for blood transfusion from 2014 to 2016 were included. The control group was healthy blood donors. Chi square test was used to assess the difference among the compared groups. Risk was calculated by regression analysis. P value <0.05 was considered as statistically significant at 95% confidence interval.Results: Out of 1000 cases and 1000 controls, O blood group were seen in 377 (37.7%) and 395 (39.5%) cases and control, respectively. Significant reduced odds ratio (OR) in non O blood groups for head and neck, esophagus, stomach, and breast was observed. In case of carcinoma cervix, OR for B group was 1.5 (P=0.05), and for blood group A OR=2.2 (P=0.02) was seen in carcinoma ovary.Conclusions: In the studied population, patients with O blood group are at an increased risk of developing head and neck, esophagus, stomach, and breast cancers.
ABO blood groups have been proposed to influence malaria parasite infection and disease severity in individuals residing in different geographical areas. In Thailand, genetic polymorphisms of blood groups and susceptibility to malaria infection have rarely been investigated. The aim of this study was to assess the genotype frequencies of ABO and Duffy blood groups and susceptibility to malaria infection in two populations residing in malaria-endemic areas of Thailand. 1100 malaria samples and an identical number of samples from healthy subjects were collected from Thai-Malaysian and Thai-Myanmar areas. Genotyping of ABO and Duffy blood groups was performed by sequence specific primer-polymerase chain reaction. The distribution of ABO and Duffy blood groups was similar in malaria-positive and negative subjects. Blood group O was prevalent in both populations followed by blood group B (BO genotype) and A (AO genotype), respectively. In Plasmodium falciparum infections, blood group A frequency was significantly higher in Thai-Malaysian samples (P = 0.042) whereas blood group B frequency was significantly higher in Thai-Myanmar samples (P = 0.022). FY*A/*A frequency was significantly higher in Plasmodium vivax infection (P = 0.036) while FY*A/*B frequency was significantly higher in healthy subjects (P = 0.005). The different ABO blood group frequencies in the two populations may contribute to susceptibility to P. falciparum infection and the high prevalence of FY*A/*A can confer a risk of P. vivax infection. Further research in various ethnic groups is needed to clarify the association between blood groups and pathogenesis of malaria.
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Os avanços da genética molecular permitiram o entendimento das bases moleculares do locus ABO. Considerando sua importância como marcador genético e suas aplicações, o objetivo deste estudo foi verificar a distribuição dos genótipos ABO em uma amostra da população brasileira oriunda da região noroeste do Estado de São Paulo, Brasil. O DNA genômico extraído de 324 doadores de sangue (150 do grupo O; 118 do grupo A; 32 do grupo B e 24 do grupo AB) foi amplificado por Polymerase Chain Reaction e digerido com enzimas de restrição. Quatorze genótipos foram identificados e as freqüências relativas dos genes O¹, O1v, O², A e B foram estimadas em 44,6%, 16,9%, 4,1%, 25,3% e 9,1%, respectivamente. Estes resultados demonstram que o locus ABO apresenta elevado polimorfismo quando analisado por métodos moleculares.
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Blood-group antigens are found on the surface of urothelial cells and may affect bacterial adherence and thereby the susceptibility to urinary tract infection. We determined the ABO, P, and Lewis blood-group phenotypes in 49 white women with histories of recurrent urinary tract infections and compared them with those found in 49 healthy control women without recurrent urinary tract infections. There was no significant difference between the two groups in the distribution of the ABO or P phenotypes. The distribution of Lewis blood-group phenotypes among control women was similar to that in the general population: secretor phenotype (Le(a-b+)), 74 percent; nonsecretor phenotype (Le(a+b-)), 18 percent; and recessive phenotype (Le(a-b-)), 8 percent. The following distribution was noted among the women with recurrent urinary tract infections: secretor phenotype, 45 percent; nonsecretor phenotype, 29 percent; and recessive phenotype, 26 percent (P = 0.002). When the women with nonsecretor and recessive phenotypes were combined and considered collectively, the odds ratio (an estimate of relative risk of recurrent urinary tract infection) for those without the secretor phenotype was 3.4 (95 percent confidence interval, 1.5 to 7.9). We conclude that there is an increased frequency of the Lewis blood-group nonsecretor (Le(a+b-] and recessive (Le(a-b-] phenotypes among women with recurrent urinary tract infections.
The discovery of the RH blood group system by Levine and his colleagues (1939, 1941a, b) was associated with the historical description of a fetomaternal alloimmunization responsible for the hemolytic disease of the newborn. The intrauterine fetal death was caused by a maternal antibody directed against an antigen on the surface of her infant’s red cells which was inherited from the father. This antibody had crossed the placenta and destroyed the fetal red cells.
The Kell blood group system was named after the person who made the first recognized antibody. Other than ABO, the Kell antigens are perhaps only second to the D antigen in the Rh system as potent immunogens. About 5% of K:−1 persons who are transfused with a single unit of K:1 red cells make anti-K1 IgG. The Kell blood group system is important not only in transfusion but also clinically since K1 is present on red cells of fetuses and maternal alloimmunization may cause hemolytic disease in the newborn.
We defined the chemical structure and the genetic control of the various A or B determinants expressed by pyloric and duodenal epithelial cells by indirect immunofluorescent staining using monoclonal anti-A or anti-B reagents that recognize only certain variants of A or B antigenic determinants. Some mucous cells in pyloric and Brünner's glands express AY or BY antigens whereas other mucous cells in the same glands express only the Y antigen. Absorptive and goblet cells of the duodenal villi and Lieberkühn glands express mono- and difucosylated A or B structures, mainly of type 1. The pyloric surface epithelium expresses mono- and difucosylated, type 1 and type 2, A or B structures. In addition, A or B antigens, with a so far undefined structure are found in the pyloric surface mucosae of non-secretor individuals.
The histo-blood group ABO, the major human alloantigen system, involves three carbohydrate antigens (ABH). A, B and AB individuals express glycosyltransferase activities converting the H antigen into A or B antigens, whereas O(H) individuals lack such activity. Here we present a molecular basis for the ABO genotypes. The A and B genes differ in a few single-base substitutions, changing four amino-acid residues that may cause differences in A and B transferase specificity. A critical single-base deletion was found in the O gene, which results in an entirely different, inactive protein incapable of modifying the H antigen.
Traditional blood group ABO serology is based on immunoreactivity with the carbohydrate determinants A, B and H antigens. Recent advances at the DNA level of the ABO genes have provided a molecular genetic model for the ABO polymorphism. This genetic model has to date only been tested on a limited basis. The present study was initiated to evaluate the universality of the proposed genetic model on a larger group of serologically defined ABO phenotypes. Three hundred healthy Danish blood donors were analysed (A:50, B:50, AB:50, O:150) by PCR amplification followed by diagnostic restriction enzyme cutting. In all cases A, B, and AB at least one allele of correctly predicted status was found. However, in O phenotype individuals, 11 out of 150 carried one allele discordant to the proposed genetic model. This novel O allele (3.7% allele frequency) was further characterized by diagnostic restriction enzyme analysis in two positions divergent between A and B alleles and by DNA sequencing of the two major exons. The novel O allele is termed O2 as it typed as B in nucleotide position 526 and as A in positions 703, 796, and 803, in contrast to the most predominant O allele termed O1, which types as A in all 4 positions. The structural defect in the O2 allele appears to be an additional substitution at nucleotide position 802. The results clearly demonstrate that with the addition of the two distinctly different O alleles, O1, O2, the previously proposed molecular genetic basis of the ABO polymorphism is quite valid.(ABSTRACT TRUNCATED AT 250 WORDS)
Our aim was to investigate the effect of misoprostol on NSAID-induced gastroduodenal mucosal damage in patients with rheumatoid arthritis. The study included 40 patients, and it was designed as a double-blind, placebo-controlled trial. Misoprostol significantly reduced the gastroduodenal mucosal lesions found at endoscopy (P < 0.05) and prevented the development of ulcers. The cumulative incidence of ulcers at four weeks was 5% in the placebo group and 0% in the misoprostol group. The basal and pentagastrin-stimulated acid output as evaluated after 23 days of treatment with misoprostol was not significantly affected. Forty-one percent of the patients had signs of current Helicobacter pylori infection, 33% had positive serology only, and 26% had no evidence of infection. Most of the patients with current infection belonged to blood group O (P < 0.05). Misoprostol treatment did not affect the occurrence of Helicobacter pylori or the rheumatic disease activity. It is concluded that the protective actions of misoprostol on the gastroduodenal mucosa of NSAID-treated patients are largely mediated by mechanisms other than inhibition of acid secretion. The relationship among active Helicobacter pylori infection, blood group O, and peptic ulcer may be helpful to identify a subpopulation of patients taking NSAIDs at risk of developing peptic ulcers.