Analysis and evaluation of 670 convalescent plasma samples from patients with COVID-19 infection

ABSTRACT

Objective: To systematically analyze the 670 convalescent plasma (CP) samples from patients with coro-navirus disease 2019 (COVID-19). Methods: The plasma samples were analyzed and evaluated for routine test items including hepatitis B virus surface antigen (HBsAg), hepatitis C virus (HCV) antibody, human immunodeficiency virus (HIV)-l/HI V-2 antibody, Treponema pallidum (TP) and alanine aminotransferase (ALT) as well as blood group, nucleic acid of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), IgG antibody, methylene blue residue and sterility. Results: A total of 121 substandard plasma samples were detected from 670 convalescent plasma samples, of which substandard IgG antibody titer accounted for the highest proportion of 7. 91%. In the turn of proportions, the blood groups were A (32. 52%), B (29. 94%), 0 (28. 886%) and AB (8. 66%). Ml the test results of nucleic acids of SARS-CoV-2 were negative. A total of 485 samples were from Wuhan, of which the highest proportion (21. 95%) were from the donors at ages of > 30 ∼ 35 years, including 264 males and 221 females. Of the high titer plasma, those at titers of not less than 1 640 accounted for the highest proportion (77. 43%). Most of the IgG titers in plasma of common patients were not less than 1 640 > 10 - 20 d, while were less than 1 160 3 ∼ 10 d, after hospitalization. However, 35 plasma samples were negative for IgG antibody (at titers of less than 1 80), in 9 of which other pathogens were detected. Conclusion: Unqualified IgG titer was the main reason for unqualified CP. The proportion of CP of group O was lower than that of the group in healthy population. The highest proportion of plasma donors in Wuhan was in the populations at ages of > 30 ∼ 35 years, which was higher in males than in females. Satisfactory immune responses were induced in most of patients in convalescence period, which removed the virus in vivo effectively. High antibody titers were induced > 10 ~ 20 d after hospitalization, making the common cases were not easy to change into severe ones. It was speculated that patients negative for IgG antibody might be infected with other pathogens. © 2020 Changchun Institute of Biological Products. All rights reserved.