I had a few questions regarding Convalescent Plasma Therapy
Why can't we use whole blood rather than convalescent plasma only? or Plasma + WBC (Adoptive cell transfer). This way we will transfer not only a humoral response but the cell-mediated immune response as well into the recipient. This should theoretically lead to a better outcome.
By giving plasma only, we transfer humoral immunity (in the form of immunoglobulins/antibodies) to the recipient and not the cell-mediated immunity.
The second question: Is there any difference if we use "serum" rather then plasma? I don't see if there is any need of adding "clotting factors" to the recipient's blood by using plasma rather then sera.
Convalescent Plasma therapy -REF : https://pubmed.ncbi.nlm.nih.gov/32356910/
Convalescent plasma rather than whole blood from recovered COVID-19 donors is preferred because the immunity to SARS-Cov-2 is mainly mediated by humoral mechanisms.
Another reason could be logistic. Very few recovered COVID-19 people are forthcoming to donate their plasma particularly after recovering from a frightening illness. This is one of the reason, why plasma convalescent therapy is not as commonly used as it should be. By telling them that 200-250 mls of plasma will be needed tilts them to donate.
Why Convalescent plasma because the immunity to viruse mainly mediated by humoral Factors.
Convalescent Plasma therapy -REF : https://pubmed.ncbi.nlm.nih.gov/32356910/
can you view this link
https://www.researchgate.net/deref/https%3A%2F%2Fpubmed.ncbi.nlm.nih.gov%2F32356910%2F
Dear Aizaz Ul Haq , very interesting query! You are right, COVID-19 patients usually do not require clotting factors, rather many of them develop a hypercoagulable state. Again, you told about whole blood which is not indicated because hemoconcentration and high hematocrit are observed in many patients (see the reference below please). So, they do not require RBC also. But, serum could be the right choice as per your proposal. Thanks.
Preprint COVID-19 and erythrocytes aggregates: An intensivist's exper...
I don't think it's clinically feasible to inject someone with foreign WBCs, since that could result in hypersensitivity reactions. It would require an exponentially great budget to extract lymphocytes responding to the infection from one recovered patient, and transfer it to another. Also, host lymphocytes only recognize certain HLA molecules that are present on the surface of the nucleated cells in the host's own body. In terms of cellular immunity, CD8+ cells actively destroy the infected cells in one's body, and it would not be wise to transfer these killer cells from one person to another, since in most of the cases the patients are able to initiate their own cellular immunity, hence, the tissue destruction occurring in the lungs. The goal of convalescent serum therapy is to cease viremia, i.e., shedding of the virus into the blood. And viremia can only be halted through humoral immunity, not cellular.
Serum is also a safer option compared to plasma, since fibrinogenin the plasma is still a foreign material.
Plasma is sufficient to give Humoral immunity which theoretically is required even though studies have not yet proven significant benefit on a large scale.
Adding other blood products increases reactions specially by adding leucocytes.
So primum non nocere
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