Coronavirus disease (COVID-19) has quickly spread around the world, resulting in a world wide high mortality and morbidity economic recession as well as a health problem in several countries and regions1. The World Health Organization (WHO) declared it a pandemic on March, 11, 2020, with 114 countries affected by that time2.
Genetic variants in the ABO gene trigger the ABO blood group phenotype. This gene has been related to a number of other traits, most importantly risk factors for COVID-19 morbidity and mortality. ABO variants, for example, have been related to angiotensin-converting enzyme production, red blood cell count, hemoglobin concentration, hematocrit, von Willebrand factor and venous thrombosis in genome-wide association studies. According to a meta-analysis, a non-O blood type is one of the most significant genetic risk factors for venous thromboembolism, along with individual variants. These criteria apply to COVID-19 as well. Coagulopathy, for instance, is a common problem for COVID-19 patients and the risk of venous thromboembolism should be carefully controlled3.
The multiple correlations between diseases and blood type as well as COVID-19 offer evidence to suggest that true relationships between blood type and morbidity and mortality due to COVID-19 which exist. Furthermore, previous research has found connections between ABO blood groups and a range of infections or disease severity after infections, such as SARS-CoV-1 and P. falciparum, H. pylori and Hepatitis B virus4.
In contrast to ABO, Rh (D) phenotypes (positive and negative Rh blood types) are correlated with relatively few diseases. Rh type as ABO, is essential for type compatibility and immune response. If Rh (D) is mismatched between mother and offspring, for example, hemolytic disease of the newborn is a problem. Many researchers have discovered proof that Rh-positive people are shielded from the consequences of latent toxoplasmosis, despite the fact that Toxoplasma gondii is a eukaryotic parasite rather than a virus like SARS-CoV-25. The aim of this study was to determine the most susceptible blood groups for COVID-19 Sudanese patients suffering from different chronic diseases.
MATERIALS AND METHODS
Study design: This research was a case study that was carried out in the state of Khartoum (Aliaa Hospital). The research was conducted from October, 2020 to January, 2021 in Sudanese patients with COVID-19 as the study population, with both genders participating. A structured questionnaire was created to collect personal information about the study group, such as age, gender, other diseases and disease duration.
Inclusion criteria: The research was carried out on patients who had been diagnosed with COVID-19 and were undergoing treatment.
Exclusion criteria: Non-COVID-19 patients were removed from this study.
Methods: A capillary blood was collected by finger pricking using 70% isopropanol and sterile disposable lancet. Three drops of the sample were added to a clean slide labeled with Anti-A, Anti-B and Anti-D.
Agglutination happened on slides containing cells positive (possessing the antigen) for the corresponding antigen when red cells were combined with different antisera (soluble antibody) reagents. There was no agglutination in the red cells that did not contain the corresponding antigen. Three drops of blood were applied to each labeled slide, followed by one drop of anti-sera A, anti-sera B and anti-sera D (Bio-Rad Laboratories, Inc.) and carefully mixed with a separate applicator stick, until agglutination was detected and the result was registered. Before using, all reagents were checked.
Agglutination of patient or control blood samples with anti-D serum (Bio-Rad Laboratories, Inc.) indicating the presence of the D antigen on the red blood cells. Absence of agglutination suggests a negative test result, indicating that the D antigen is not detectable. If Rh typing is negative, Du typing will be done consequently6.
Du method (the indirect anti globulin): The indirect anti globulin test detects antibodies that can induce red cell sensitization in vitro. If serum contains both IgG antibodies and the corresponding antigens, red cell mixture incubation will allow the antibody to bind to the antigenic receptor on red cells.
In a 10×75 mm test tube, two drops of anti-D mixture (IgG and IgM) were added. One drop of washed 5% suspension of the test cell was applied, mixed well and the tube was incubated at 37°C for 15 min in LISS. After incubation, the mixture was centrifuged and the results were read and registered. The mixture was washed 3-4 times in large volume of saline and each wash was decanted fully. Two drops of anti-globulin reagent were applied, mixed thoroughly and incubated at room temperature for 4-5 min. The mixture was centrifuged at 3400 rpm for 15 sec and the final results were read and registered6.
Ethical consideration: The study obtained ethical clearance from the National University and a written consent has been obtained from the participants after a good discussion with them and the result of the study would be utilized for their benefits.
Data analysis: The Statistical Package of Social Sciences (SPSS) was used for statistical analysis version 23. Frequency and student T-tests have been used to display the data. Reports were evaluated at significance of p<0.05.
The study included 200 participants divided evenly into case (patients with COVID-19) and control groups (healthy). The demographic data were classified based on case group age, gender, other chronic disease and ABO blood group and Rh D antigen results. As shown in Fig. 1, the majority of participants were male 56% and female 44% for the case study
and male 44% and female 56% for the control study. In our research, the most common blood type was O positive 24.5%, while AB positive was the least common (as shown in Fig. 2).
The following percentage distribution of chronic diseases other than COVID-19: Asthma (6%), stomach ulcer (1%), renal failure (10%), diabetes (12%), hypertension (24%), vein thrombosis (1%), thrombosis (1%), cardiac disease (2%) and sinusitis (1%) was illustrated in Fig. 3 When case and control were compared, there was a strong correlation since p<0.05 as shown in Table 1. The presence of D antigen in case and control has no significant correlation as seen in Table 2 but there was a significant correlation when ABO and D antigen in case and control were compared p<0.05 as shown in Table 3.
The study found a correlation between Renal Failure and the mean of duration of COVID-19 in the case group. The study also found no correlation between Asthma, Stomach Ulcer, Diabetes, Hypertension, Vein Thrombosis, Thrombosis, Heart diseases and Sinusitis (Table 4).
||Gender distribution in case and control
||Percentage of blood groups in the study population
|Table 1:||Correlation between ABO blood group among case and control study
|Table 2:||Correlation between Rh D antigen among case and control study
|Table 3:||Correlation between ABO blood group and Rh D antigen among case and control study
|Table 4:||Correlation between other diseases and Mean duration of COVID-19 among case group
|Fig. 3:||Percentage of chronic diseases among study population
In current study, it has been found that ABO blood group system may have played an important role in the COVID-19 mode of infection. Blood group AB has the lowest chances of acquiring the COVID-19 virus, while blood group O Positive has the highest. Patients with renal failure are substantially more vulnerable to COVID-19 infection over an extended period of time.
Many chronic disorders, such as vascular disease, coronary heart disease and tumorigenesis, are statistically or biologically linked to ABO blood groups7. Studies on the relationship between blood groups and some viral infections have received much interest in recent years. Investigating the role of different blood groups in viral infection can be useful in evaluating a person's susceptibility to a virus. Previous research has found a connection between ABO blood groups and host susceptibility to infectious diseases such as SARS-CoV8, malignant tumors9, Helicobacter pylori10, Norwalk virus11 and hepatitis B virus7. The correlation between ABO blood groups and SARS-CoV, in particular, led to the presumption of a related susceptibility to COVID-19.
This study found no association between ABO blood groups and the distribution of Asthma, stomach ulcer, diabetes, hypertension, vein thrombosis, thrombosis, heart disease and sinusitis but there was a significant correlation between renal failure and duration of COVID-19.
The current study revealed that patients with blood group type O positive are the most likely to be infected with the COVID-19 virus, which was consistent with Flegel's studies in France, which found that patients with blood type O were more likely to be infected with COVID-1912 and inconsistent with Boudin et al., 202013, which indicated that Canadian patients with blood type O were less likely to be infected with chronic diseases. While Ray et al., 2020 discovered that in Turkish patients with blood type O were less infected and those with blood type A were less correlated with mortality, they also discovered a negative harmonious relationship between the O blood group and COVID-19 exposure14. They found no significant link between blood group and the need for intubation or COVID-19-related mortality, which may be attributed to their small sample size. Zeng et al., 2020 discovered a higher risk of COVID-19 exposure in subjects with the A blood group in another study. In another study, individuals with blood group O were found to be less susceptible to extreme COVID-19 but they were unable to determine if having O blood group provided defense against the virus15. The authors concluded in a large multi-institutional retrospective study that there is no relationship between blood type and the likelihood of severity development, the need for intubation or death. These findings contradicted the findings of Zhao et al., 202016, who investigated the relationship between blood type and death rate in the Wuhan experience.
COVID-19 viruses developed in individuals from groups A, B, AB and O, respectively, express A, B, A and B antigens and none. Anti-A, anti-A, none and anti-A/anti-B/anti-A, B antibodies are present in people in groups A, B, AB and O, respectively17. Anti-A, Anti-B and Anti-A, Antibodies can reduce an individual's risk of infection from the SARS-CoV-2 virus, making type O individuals more vulnerable. The blockage may or may not be complete. However, once an infection has been created, individuals produce viruses of their own ABO types and the Anti-A, Anti-B and/or Anti-A, B antibodies they possess can no longer neutralize newly produced viruses.
Individuals with blood type O negative are at a lower risk of viral infection17. Anti-A, Anti-B and/or Anti-A, B antibodies can prevent the viral spike glycoprotein from interacting with cellular ACE2 receptors. This can prevent the SARS-CoV-2 virus from entering cells and neutralize it in a complement-dependent manner. It may also facilitate the production of cytotoxic T cells. Immunity to other viral antigens can develop as a result17.
It is possible that the ABO blood group system played a significant role in the COVID-19 mode of infection. Blood group AB is the least likely to be infected with the COVID-19 virus, whereas blood group O Positive is the most likely.
This Publication was supported by the Deanship of Scientific Research at Prince Sattam bin Abdulaziz University.