Clinical and immunological benefits of convalescent plasma therapy in severe COVID-19: insights from a single center open label randomised control trial

A randomised control trial was done to assess clinical and immunological benefits of passive immunization using convalescent plasma therapy (CPT), compared with standard of care, in severe COVID-19 patients presenting with acute respiratory distress syndrome (ARDS). Plasma abundance of a large panel of cytokines was quantitated before and after intervention to assess the effect of CPT on the systemic hyper-inflammation encountered in these patients. Transfused convalescent plasma was characterized in terms of its neutralizing antibody content as well as proteome. While across all age-groups clinical outcomes were not significantly different, significant immediate mitigation of hypoxia, reduction in hospital stay as well as significant survival benefit were registered in severe COVID-19 patients with ARDS aged less than 67 years receiving CPT. In addition to its neutralizing antibody content, a significant effect of the anti-inflammatory proteome of convalescent plasma on attenuation of systemic cytokine deluge, contributed to the clinical benefits of CPT.