Introduction
The number of SARS-CoV-2 (Covid-19) cases, which was recognized as a
pandemic by the World Health Organization (WHO) in March, continues to
increase rapidly worldwide.1 As of July 2020, the
number of Covid-19 patients reported by WHO has exceeded 13 million and
the number of deaths 580 thousand. People
most commonly affected by Covid-19 are those with chronic lung or
cardiovascular diseases, men with hypertension and
diabetes.2 There are some parameters such as CRP,
ferritin and LDH that can predict the clinical severity of Covid-19, but
there are no biomarkers indicating a predisposition to
Covid-19.3
The general blood group system called ABO discovered by Landsteiner is a
kind of cell identity system determined by the antigenic structure
located on the erythrocyte surface. The Rh system, known as whether
there is an antigenic structure or not, is another
grouping.4 Blood groups are a qualitative
characteristic in which there are no environmental effects, with all of
the phenotypic variation being a reflection of the genetic structure.
Blood group antigens are genetically encoded, and these antigens may be
a predisposing factor for some diseases and a protective factor for some
others. Studies have shown that some rheumatological diseases, viral
infections such as Norwalk virus and Hepatitis B, and some types of
cancer are associated with the ABO blood group.5-8 In
addition, it has been found that the rate of infection with SARS
coronavirus is lower in blood group O.9
By examining the relationship of the human blood group with virus
infection, it is possible to determine the susceptibility of people with
different blood types to viruses. There are some studies examining the
relationship between Covid-19 and blood groups in the literature. The
aim of this study was to investigate the ABO and Rh blood group
distribution and clinical characteristics in patients with Covid-19.