Inflammatory markers and auto-Abs to type I IFNs in COVID-19 Convalescent Plasma

ABSTRACT

Background: COVID-19 convalescent plasma (CCP) contains neutralizing anti-SARS- CoV- 2 antibodies that may be useful as COVID-19 passive immunotherapy in patients at risk of developing severe disease. Aim(s) Such plasma from convalescent patients may also have additional immune-modulatory properties when transfused to COVID-19 patients. Method(s) CCP (n = 766) were compared to control non-convalescent plasma (n = 166) for soluble inflammatory markers, ex-vivo inflammatory bioactivity on endothelial cells, neutralizing auto-Ab to type I IFNs, and reported adverse events in the recipients. Result(s) CCP exhibited significantly higher IL-6 and TNF-alpha (0.531+/-0.04 vs 0.271+/-0.04;p = 0.0061 and 0.900+/-0.07 vs 0.283+/-0.07 pg/ml;p < 0.0001), respectively) and lower IL-10 (0.731+/-0.07 vs 1.22+/-0.19 pg/ ml, p = 0.0034) levels than control plasma. Other inflammatory markers as well as ex-vivo bioactivity did not differ significantly between CCP and control plasma. Neutralizing auto-Abs against type I IFNs were detected in 14/766 (1.8 %) CCP. They were not associated with reported adverse events when transfused (n = 14). Inflammatory markers and bioactivity in CCP with or without auto-Ab, or in CCP associated or not with adverse events in transfused patients, did not differ significantly. Overall, CCP exhibited moderately increased inflammatory markers compared to control plasma with no discernable differences in ex-vivo bioactivity. Auto-Ab to type I IFNs, detected in a small fraction of CCP, were not associated with reported adverse events or differences in inflammatory markers. Conclusion(s) Further defining the clinical relevance of these findings will require further studies including careful clinical evaluation of patients treated with CCP.