Single intravenous infusion of convalescent blood plasma imparted a great recovery in an immunocompromised old lady who was suffering from a prolonged fatal and deteriorating COVID-19 illness and severe pneumonia, as per the physicians at the University of Alabama at Birmingham, published in the journal Cell Reports Medicine.
According to the study, this 72-year-old woman was hospitalized 33 days after the onset of COVID-19 symptoms. It was a great challenge to mount her immune defense against the SARS-CoV-2 virus as she had a long-standing immunocompromised condition - chronic lymphocytic leukemia.
The physicians noted a remarkable and profound improvement in her symptoms - a rapid drop of 104-degree F fever, just after 48 hours of a single dose of intravenous infusion of convalescent blood plasma from her son-in-law -- who had recovered from COVID-19 disease.
The study showed that the woman's recovery was due to an extremely high virus-neutralizing titer in the son-in-law's donated plasma that persisted in her four days after infusion. This titer was very much higher than those measured in 64 other remnant convalescent plasmas collected by two blood banks.
The lower cut-off value for emergency use authorization of convalescent plasma by the Food and Drug Administration is neutralizing antibody titers above 250. Convalescent plasmas titers above 250 from the first blood bank were only 37% whereas plasmas from the second blood bank that exceeded the neutralizing antibody titer cut-off of 250 were only 47%. Therefore, most of these plasmas were inadequate for transfusion.
Almost 8 convalescent plasmas obtained from the second blood bank outnumbered the neutralizing antibody titer of 1,000. However the neutralizing antibody titer of the son-in-law's plasma was extremely high, up to 5,720. Thus, not all the plasma donors had sufficient neutralizing titers.
The team evaluated the plasma titers in other 17 patients apart from the 72-year-old woman, both before and after they were given convalescent plasma for treatment of COVID-19. Before infusion of plasma. It was seen that 53% of these patients had neutralizing antibody values greater than 250, and 7 of the patients had titers greater than 3,000.
The infusion of convalescent plasma had no significant impact on their pre-existing neutralizing antibody titers in about 16 patients. In fact, many of the recipients had existing endogenous neutralizing antibody responses beyond the effect of administered convalescent plasma units.
"Convalescing individuals with truly high-titer neutralizing antibodies are rare, which underscores the need for a concerted effort to identify them but also poses the question of whether there are ample numbers of suitable convalescent plasma donors. The generally low neutralizing antibody titers in most donors, as well as high titer baseline neutralizing antibodies in many recipients, highlight the importance of first testing the convalescent plasmas, and also the recipients. Doing so should optimize the clinical benefit and reduce the effort spent when convalescent plasma therapy is not appropriate", says Randall Davis, M.D., a professor in the UAB Department of Medicine and his colleagues.