Minimally reduced levels of anti-Spike IgG after nine COVID-19 convalescent plasma donations: a case report

Abstract

Despite intensive research, the physiology of the serological response to SARS-CoV-2 infection and its dynamics during the recovery period remain incompletely understood. Regulation of the immune response seems all the more important as it plays a role in both virus clearance during infection and the potential development of long-term resistance to reinfection. A case of convalescent plasma donor is described in whom was observed a prolonged enhanced immune response to infection in the form of a persistently high level of anti-Spike IgG despite subsequent plasma donations. The presented donor experienced COVID-19 interstitial pneumonia, requiring pharmacotherapy in a hospital setting (therapy involving azithromycin, chloroquine and protease inhibitors), which allowed him to achieve remission. The described donor donated plasma nine times during convalescence, each time showing a satisfactory level of anti-Spike IgG. The presented case highlights the multifactorial regulation of the serological response in the course of SARS-CoV-2 infection, which may include the long-term effect of pharmacotherapy, especially in the field of antiretroviral drugs. While the authors are not yet able to clearly define the importance of antiretroviral therapy in regulating the humoral response in COVID-19 patients, it is supposed it may be important in the subsequent antibody production.