Comparison of the Effects of Plasmapheresis, Hemoperfusion, and Convalescent Plasma Therapy on Inflammatory Factors in COVID-19 Patients.

Background: Since the emergence of coronavirus disease 2019 (COVID-19), the treatment protocols are continuously updated, based on the evidence gathered all around the world and reported to the World Health Organization. Like many other emerging infectious diseases, using convalescent plasma from those recovered from the disease was a preliminary treatment approach that showed partial effectiveness for severe COVID-19 patients. Besides, blood filtration strategies, such as hemoperfusion and plasmapheresis, are employed to lessen the load of inflammatory molecules. However, few studies compared their effects to conclude which treatment might be more efficacious for COVID-19 patients. We compared the effects of plasmapheresis or plasma exchange, convalescent plasma therapy, and hemoperfusion on O2 saturation and inflammatory factors in COVID-19 patients. Methods: In this retrospective study, 50 COVID-19 patients received standard treatments based the international guidelines. Patients were divided into 4 groups: hemoperfusion, plasmapheresis, plasma therapy, and control. The control group received only the standard treatments. The mortality rate, O2 saturation, and laboratory factors were compared between the 4 groups. Results: We found a significant decrease in the C-reactive protein level following hemoperfusion (32.75 ± 23.76 vs 13 ± 7.54 mg/dL; p = 0.032) but not plasmapheresis and plasma therapy. Besides, serum levels of lactate dehydrogenase (p = 0.327, 0.136, 0.550, for hemoperfusion, plasmapheresis, and plasma therapy, respectively) and other inflammatory molecules did not significantly change following treatments. There is also no significant difference in the mortality rate between the treatment groups (p = 0.353). Conclusion: It seems that hemoperfusion, plasmapheresis, and plasma therapy did not have considerable effects on decreasing the inflammation and mortality rate compared with standard treatment.