الفهرس 
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Abstract
Coronavirus disease 2019 (COVID-19), is currently one
of the worst pandemics reported ever. Severe Acute Respiratory
syndrome Coronaviridae 2 (SARS-CoV2), the culprit of
COVID-19, is a highly virulent virus, resulting in an acute form
of respiratory distress that was declared by the World Health
Organization (WHO) declared as a global pandemic
(AbdelMassih et al., 2020).
Many researchers have related the variability of the host
to the disease susceptibility to different pathogens according to
the difference in ABO blood groups. Blood group antigens may
act as receptors to pathogens, affecting pathogenic pathways
and modifying the immune response (Shamikh et al., 2021).
Recently, many studies have discovered relationships
between ABO blood group system and SARS-COV-2 infection,
severity and demise. However, the results of these studies are
contradictory. The contradiction between the results could be
attributed to different sample sizes or population heterogeneity
(Wu et al., 2020 A).
This case-control study was conducted on 400 COVID19 confirmed patients either home isolated patients or those
recruited from Ain Shams University hospital wards and
intensive care units. To represent the ABO blood distribution
among the general population, the blood types of 400 healthy
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individuals who donated blood at the central blood bank of Ain
Shams University Hospitals were also obtained.
A nasopharyngeal and/or oropharyngeal swabs were
obtained for the diagnosis of COVID-19 infection by
polymerase chain reaction (PCR) and anticoagulated venous
blood were also collected from each subject to perform
ABO/RhD blood grouping by either gel card agglutination or
automated methods.
Blood group typing of the studied COVID-19 patients
showed that blood group A was the predominant being found in
32.5%, followed by O+ (32%) then B+ (25%) and AB was the
least common (9.5%). 90% of these patients were Rh positive
while 10% were negative. Phenotyping of our patients was
almost identical to the that of the enrolled healthy blood
donors. The frequencies of A, O, B and AB were 32.8%,
30.3%, 22% and 8% respectively.
Severity analysis of our patients has shown that anti-A
harboring blood groups (O and B) were mostly presented as
severe and critical cases unlike groups lacking anti-A
antibodies (A and AB groups) that were seldom characterized
with complicated diseases.
We attempted to account for these differences by
analysis of different laboratory and clinical findings that are
considered as useful markers of disease severity and outcome in
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COVID-19. Patients of O group were presented with anemia
and high LDH levels. Moreover, O and B patients were also
associated with markers of COVID-19 coagulopathy where O
patients had prolonged APTT whereas B patients were
significantly associated with high D-Dimer levels.
Our data also revealed that blood group A and AB
patients were predominantly moderate and mild COVID-19
cases. Laboratory investigations of the current patients showed
that blood group A wasn’t associated with poor prognostic
markers such as low hemoglobin levels, prolonged APTT or
high ferritin levels. Besides, a significant association was found
between AB group and higher lymphocytic counts compared to
non-AB patients indicating a favorable course of the disease.