NEW DELHI: Days after findings of an ICMR study showed that plasma therapy may be ineffective for Covid-19 patients, another research funded by the health research body has renewed hopes on the efficacy of this interim strategy for the infectious disease.
The latest research says that its success could be dependent on the quality of antibodies being used. This, in effect, means that the plasma therapy cannot be completely written off for the disease and the key to ensuring its success could lie in identifying the donors with the right levels of neutralising antibodies.
The new research had been carried out by scientists at the International Centre for Genetic Engineering and Biotechnology, in collaboration with ICMR-National Institute of Malaria Research, Department of Biotechnology and the Emory Vaccine Center, Atlanta.
A study led by ICMR based on a randomised control trial, whose findings were released last week had shown that 34 patients who received plasma therapy died while 31 patients who did not receive it, succumbed to the infection. Also, 17 patients in each group progressed to have severe disease.
It had however also highlighted the urgent need for prior measurement of neutralizing antibody titres in donors and participants, which may better aid in delineating the role of plasma therapy in Covid-19 management.
In medicine, titer means the concentration of an antibody, as determined by finding the highest dilution at which it is still able to cause agglutination of a disease causing element in the virus — antigen.
Neutralizing antibodies, typically of IgG type that can potentially block infection, are key components for the success of plasma therapy and titers of over 320 are generally considered suitable for successful plasma therapy.
Currently, however, mere presence of IgG antibody, regardless of its neutralizing ability, is used as a selection criterion for donor convalescent plasma because assessment of neutralizing antibodies in routine clinical samples remains a challenge.
Thus, it is important to note that we have insufficient knowledge to understand whether all donors had sufficient titers of neutralising antibodies to donate plasma, and whether these titers reflected in all recipients that received the transfusion, the authors of the new study have said.