ABO blood group alleles and genetic recombination

Ludwik Hirszfeld: A pioneer of transfusion and immunology during the world wars and beyond

Ludwik Hirszfeld (1884-1954) was a Polish physician, immunologist and microbiologist. Together with Emil von Dungern, he showed that blood groups are heritable traits and established the terminology of the ABO blood group system. He discovered A₁ and A₂ blood groups, and showed for the first time, in a large-scale population study, that blood group frequency differs between populations. During World War I, he volunteered as an army physician. In the interwar period, he helped to create the National Institute of Hygiene in Warsaw and was instrumental in developing transfusion centres in Poland. During World War II, which he barely survived, he co-organized secret medical courses in the Warsaw Ghetto and played a major role in containing the typhus epidemic that ran rampant there since 1941. After the war, he was the first in Poland to put the theory of serological conflict between mother and foetus into clinical practice, saving the lives of almost 200 children by introducing exchange transfusions.

Effect of Helicobacter pylori Eradication and ABO Genotype on Gastric Cancer Development

BACKGROUND

Evidence is lacking regarding how Helicobacter pylori infection status, eradication history, and ABO blood type affect the development of gastric cancer (GC) given the multifactorial and distinctive etiology according to cancer location (noncardia vs cardia) and histologic type (intestinal vs diffuse-type). We evaluated the effect of H. pylori infection status incorporated with H. pylori eradication history and ABO genotype on GC development according to cancer location and histologic type.

METHODS

A case-control study of 997 patients with noncardia GC (NCGC) and 1147 control subjects was performed using risk analyses with 14 factors including H. pylori infection with eradication history and ABO genotype. As final analyses, multivariable logistic regression models were fitted. Additionally, H. pylori infection status with eradication history was tested for its association with age, atrophic gastritis (AG), and intestinal metaplasia (IM).

RESULTS

The ABO genotype with the B allele was associated with a significantly lower risk of NCGC of both histologic types. The reduction in risk for NCGC by adding the B allele was more prominent in diffuse-type than that in the intestinal-type. H. pylori infection with eradication history was associated with a significantly lower risk of NCGC of both histologic types, compared with those without eradication history (odds ratio (OR), 0.22; 95% confidence interval (CI), 0.14-0.34) approaching that of uninfected subjects. Past infection status without an eradication history was associated with older age, AG, and IM.

CONCLUSIONS

H. pylori eradication and the B allele decreased the risks of the intestinal and diffuse-types of NCGC. H. pylori eradication revealed a strong association against developing NCGC. Therefore, it should be considered as a primary measure in NCGC prevention.

ABO alleles are linked with haplotypes of an erythroid cell-specific regulatory element in intron 1 with a few exceptions attributable to genetic recombination

Recent investigation of transcriptional regulation of the ABO genes has identified a candidate erythroid cell-specific regulatory element, named the +5·8-kb site, in the first intron of ABO. Six haplotypes of the site have been reported previously. The present genetic population study demonstrated that each haplotype was mostly linked with specific ABO alleles with a few exceptions, possibly as a result of hybrid formation between common ABO alleles. Thus, investigation of these haplotypes could provide a clue to further elucidation of ABO alleles.

BGMUT Database of Allelic Variants of Genes Encoding Human Blood Group Antigens

The Blood group antigen Gene MUTation (BGMUT) database documents variations in genes of human blood group systems. In March 2014, the database, accessible at www.ncbi.nlm.nih.gov/gv/mhc/xslcgi.cgi?cmd=bgmut, listed 1,545 alleles of 44 genes of 34 blood group systems. Besides allelic information, the BGMUT resource also presents comprehensive and current information on blood group systems. This review describes the database and notes its utility for the transfusion medicine and human genetics communities.

[Analysis for Eight ABO Alleles in Korean Population.]

BACKGROUND

ABO genotyping is a useful tool in case of ABO discrepancies and in legal medicine. Recent knowledge of various alleles in the ABO gene has led to the need of a different method that can cover numerous polymorphisms. We performed a polymerase chain reaction using sequencespecific priming (PCR-SSP) with 12 primer sets and evaluated its value in the detection of 8 ABO alleles.

METHODS

Genomic DNA was isolated from peripheral blood of 222 unrelated Koreans. Sequencespecific primer sets for the nucleotides 261, 297, 467, 802, 803, and 1059 were selected, and 12 PCR reactions were performed for each sample. Direct sequencing was performed to evaluate the accuracy of discrimination between A(1)(Pro) and A(1)(Leu) and between O(1) and O(1v).

RESULTS

All the ABO genotype patterns were in an exact match with the ABO phenotypes. The results from sequencing and PCR-SSP were equivalent. The allele frequencies of A(1), B, O(1), and O(1v) were 27.25%, 19.82%, 27.25%, and 25.68% respectively. Out of total 121 A(1) alleles, 6 (4.96%) were A(1)(Pro) alleles and 115 (95.04%) were A(1)(Leu) alleles. No A(2), O(2), or CisAB alleles were found in this study.

CONCLUSIONS

The proportion of O(1v) allele was similar to that of O(1) allele. This was an unexpected result. We developed a method for detecting 8 ABO alleles by PCR-SSP; the method was accurate and was able to discriminate between A(1)(Pro) and A(1)(Leu) and between O(1) and O(1v).

ABO genotype and the risk of gastric cancer, atrophic gastritis, and Helicobacter pylori infection

BACKGROUND

Although several studies have investigated the association between ABO blood type and risk of gastric cancer (GC), atrophic gastritis (AG), and Helicobacter pylori (HP) infection, no study has investigated these associations by using ABO genotype.

METHODS

We conducted a case-control study in 703 patients with GC and 1,465 noncancer patients. We also conducted a cross-sectional study by using 1,406 of these 1,465 controls, who were examined for pepsinogens and anti-HP IgG antibody levels in serum. ABO genotype was determined from single nucleotide polymorphisms in ABO gene. We used rs8176719 to mark the O allele, and rs8176746 and rs8176747 to mark the B allele. ORs and 95% CIs were calculated by a multivariate logistic model.

RESULTS

We observed significant associations between ABO genotype and GC, AG, and HP infection. ORs (95% CIs) of GC were 0.70 (0.50-0.99) for OO and 0.53 (0.36-0.77) for BO relative to AA genotype. An increased risk of GC was observed with addition of the A allele (P(trend) < 0.001), and a decreased risk with that of the B allele (P(trend) = 0.023). An OR of AG was 0.73 (95% CI, 0.53-0.99) for blood type B relative to blood type A, and an OR of HP infection was 0.39 (95% CI, 0.17-0.87) for BB relative to AA genotype.

CONCLUSION

This study identified a statistically significant association between ABO genotype and GC risk. In addition, ABO gene locus may influence AG prevalence and HP infection.

IMPACT

Further studies are necessary to confirm these findings.

ABO blood group alleles and the risk of pancreatic cancer in a Japanese population

Several studies have investigated a possible association between the ABO blood group and the risk of pancreatic cancer (PC), but this association has not been fully evaluated in Asian populations. The present study aimed to assess the impact of genotype-derived ABO blood types, particularly ABO alleles, on the risk of PC in a Japanese population. We conducted a case-control study using 185 PC and 1465 control patients who visited Aichi Cancer Center in Nagoya, Japan. Using rs8176719 as a marker for the O allele, and rs8176746 and rs8176747 for the B allele, all participants' two ABO alleles were inferred. The impact of ABO blood type on PC risk was examined by multivariate analysis, with adjustment for potential confounders to estimate odds ratios (OR) and 95% confidence intervals (CI). An increased risk of PC was observed with the addition of any non-O allele (trend P = 0.012). Compared with subjects with the OO genotype, those with AO and BB genotypes had significantly increased OR of 1.67 (CI, 1.08-2.57) and 3.28 (CI, 1.38-7.80), respectively. Consistent with earlier reports showing a higher risk of PC for individuals with the non-O blood type, the previously reported protective allele (T) for rs505922 was found to be strongly correlated (r(2) = 0.96) with the O allele. In conclusion, this case-control study showed a statistically significant association between ABO blood group and PC risk in a Japanese population. Further studies are necessary to define the mechanisms by which the ABO gene or closely linked genetic variants influence PC risk.

DNA polymorphisms and haplotypes in the 5′-upstream region of the ABO blood group gene

We investigated the polymorphisms in the 5'-upstream region between nucleotide position (nt) -9600 and nt-4105 of the ABO blood group gene using PCR and direct sequencing methods. We found 16 single nucleotide polymorphisms, two insertion-deletion polymorphisms and two sequence polymorphisms. One of the insertion-deletion polymorphisms was found at nts from -9605 to -9204, and the alleles of that locus were named ABORR*L (non-deletion) and ABORR*S (52-base-deletion). There were two haplotypes constructed from 14 polymorphisms in the region between nt-9600 and nt-7565; they were tentatively named ABORR*L-associated and ABORR*S-associated haplotypes. The ABORR*L-associated haplotype may link with ABO*O(A) (also known as ABO*O201), and the ABORR*S-associated haplotype links with the other common alleles. This indicates the existence of two major lineages of the Japanese ABO alleles in the 5'-upstream region from nt-7565. In contrast to these findings, we observed six haplotypes in the region between nt-6371 and nt-4105, and we assume that the sequence in that region is variable as compared with those in the other 5'-upstream regions. We examined the generation of two sequence polymorphisms found in the present study. In the both cases, the formation of a hairpin loop caused by palindrome in a single-stranded DNA molecule may play an important role in generating the polymorphism.