Red Blood Cells Affect Oxygen Saturation of Covid-19 Patients

The decrease in blood oxygen saturation affects the condition of Covid-19 patients. Researchers found SARS-CoV-2 infects immature red blood cells, reducing oxygen levels in the blood and also impairing the immune response.

Some people with Covid-19 experience a decrease in oxygen saturation in the blood. Oxygen saturation itself means a measure of the percentage of oxyhemoglobin or hemoglobin bound by oxygen in the blood.
The cause of the decrease in oxygen saturation in the blood was successfully revealed by a study conducted by the Faculty of Medicine and Dentistry University of Alberta, Canada. The study succeeded in explaining why Covid-19 patients, both those who were hospitalized and those who did not experience hypoxia, or low oxygen levels in body tissues.
“Low blood oxygen levels have become a significant problem in Covid-19 patients,” said study leader and professor at the University of Alberta School of Medicine & Dentistry, Shokrollah Elahi. “Therefore, we think one potential mechanism is that Covid-19 impacts red blood cell production,” Elahi continued as quoted by the June 2 issue of Science Daily.
In the study, Elahi and his team examined the blood of 128 Covid-19 patients. The patients included those who were critically ill and admitted to the ICU, who had moderate symptoms and were hospitalized, and who had a mild version of the disease or spent only a few hours in the hospital.
The results found that in those with severe COVID-19 illness, more immature red blood cells flooded the circulation. Even the composition can reach 60 percent of the total cells in the blood. In comparison, the number of immature red blood cells is less than 1 percent, or none at all, in the blood of a healthy individual.
“Immature red blood cells are in the bone marrow and we don’t usually see them in the blood circulation,” Elahi explains. “Immature red blood cells are launched to compensate for the depletion of healthy red blood cells,” he added.
Due to reduced blood cells, the body then produces significantly more red blood cells to provide sufficient oxygen to the body. Unfortunately, immature red blood cells cannot carry oxygen and only mature red blood cells can.

Vulnerable to Infection
The second problem is that immature red blood cells are very susceptible to Covid-19 infection. Because immature red blood cells are attacked and destroyed by viruses, the body cannot replace mature red blood cells which only live for about 120 days and their ability to carry oxygen in the bloodstream is reduced.
The question is how does the virus infect immature red blood cells?
According to Elahi’s previous research, immature red blood cells make certain cells more susceptible to HIV. Starting from that study he investigated immature red blood cells that have receptors for SARS-CoV-2.
“Immature red blood expresses the ACE2 receptor and coreceptor, TMPRSS2, which allows SARS-CoV-2 to infect them,” he said.
In his research, Elahi collaborated with a virologist from the Li Ka Shing Institute of Virology at the University of Alberta, Lorne Tyrrell. They performed investigative infection testing with immature red blood cells from Covid-19 patients and proved these cells were infected with the SARS-CoV-2 virus.
Elahi said the findings were interesting but also pointed to two significant consequences. First, the virus infects immature red blood cells and kills them. When that happens it forces the body to meet its oxygen supply needs by pumping more immature red blood cells out of the bone marrow.
Second, immature red blood cells are actually strong immunosuppressive cells, meaning they are able to suppress antibody production and suppress T cell immunity against viruses. When that happens it makes the patient’s condition worse.
“So in this study, we have shown that immature red blood cells mean a weaker immune response to the virus.” there is / I-1