Frequency of ABO blood group systems polymorphisms in Plasmodium falciparum malaria patients and blood donors from the Brazilian Amazon region. By RaBonni_AsiGee, Kintampo Health Research Centre / Ghana
The idea of the study is to look out for the likelihood of having distinct allele frequencies on different variations of people with malaria. A study Which was carried out some years ago has it that… people of a particular blood group have a protective advantage of developing some diseases such as malaria. This is mostly the blood group O. 98 participants were recruited for the test group comprising people who have been tested positive for falciparum malaria. ( confirmation was by Pf genomic of blood blots).
The control group also comprised 142 blood donors from four different blood banks who did not have malaria. People between the ages of 19 _65 were recruited for both groups. There was matching of ages between the 2 groups and each of the members were genetically independent
The total sample size was 240. DNA was extracted from frozen pellets to determine the genotype or blood group of each of the participants.
The group extracted the DNA using the easy DNA method and determination of various alleles frequencies and other genotypes were by PCR and RFLP
After DNA Was extracted, it Was now digested by a restriction enzyme which cuts and locates at different points of the DNA to derive the gene of interest
Amplification through PCR was done by amplifying the fragments that were covering the exons 6 and 7 Which was part of the final product.
PCR is done in a thermal cycle for over one hour.
After these processes, the final products were analysed by electrophoresis using 2% agarose gel. ( polyacrylamide). It was then stained with ethidium bromide ( cancerous) and observed under uv light to determine the bands present. These bands correspond to particular blood groups and allele frequencies ( mostly of the O blood).
The following primers were used to target the various variants and blood type forms….
Briefly, four PCR were used. The A, B, O1, and O2 genes were identified in three amplifications using the fy46/fy47, fy43/fy31 and fy47/fy29 primer pairs, respectively. Additionally, the O1 and O1v genes were distinguished using the fy47/fy31 primer pair in the last reaction
At the end of the study? Carried out in 240 participants including 98 p. falciparum malaria patients and 142 non-malaria blood donors? It Was observed that….
The table indicates that… a very high percentage of the participants ( both in the test and control group) Were of the blood group ABO* 0o1 . Making over 73 and 74 percent of the total sample size.
This was followed by ABO* A 0o 1, ABO*B 001.. some other types such as BB, AA and AB Were seen but let’s significant
This is a confirmation of a previous study that was carried out..the study confirmed that most people of the Brazilian region belonged to the blood group O. Probably because of a survival advantage. Those in O were kinda able to withstand pressures because their RBC’s were able to resist the existence and effects of the Plasmodium falciparum parasite in their system to that extent. Which might have caused those in blood group O to be more in the population as compared to other groups
An article was published in 2015 to also further confirm this. I think I posted it on here previously on the page. #why those in blood group O develop resistance.
Now everything did not end here. After realising that those in blood group ABO*O 01 Were in the dominant group ( both in the test group and control group) .. they further Went down to looks out for the different variations or forms that were present only in the blood group ABO *O 01 ( group O).
After another genotyping analysis ( using PCR and rflp)
They found other forms of the blood group O comprising O1, O2 and O1V
Interesting they were able to find these both in the control and test group and the differences in occurrence was not significant
The table below has the details.. this Was done in 30 malaria patients in 27 non-malaria patients comprising the blood donors group
The table shows there was a high frequency of the O1V in both the test group and control group ( 57 percent and 60 percent respectively…followed by 01 and then O2. Heterogeneity was seen in that of O1V, 02 and O1 but no homozygous group was observed in the allele frequency O2. However, the homozygous group was observed in O1V and O1
I Would like to conclude by saying that? expectations of the study was in a way not met because the results clearly shows that.. there was no significant differences in the genotype and allele frequencies comparing those who had falciparum malaria and those who did not have falciparum malaria.
One can therefore deduce that even though those with blood group O have a protective advantage of developing falciparum malaria? There could be other factors responsible for this but not only because of the fact that they had the genotype O and it’s variants in their blood. It can also be said that, there is no full evidence for saying that ABO histo-blood group is directly related to the incidence of P. falciparum malaria . This was also deduced by another group (Fischer and Boone, 1998).
I would therefore recommend that.. more studies be conducted in these areas to determine the direct relationship between ABO blood group systems and the incidents of falciparum Malaria