Successful Treatment of a 39-Year-Old COVID-19 Patient with Respiratory Failure by Selective C-Reactive Protein Apheresis

BACKGROUND High C-reactive protein (CRP) plasma levels in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are associated with poor prognosis. CRP, by activating the classical complement pathway and interacting with macrophages via Fc gamma receptors, can cause pulmonary inflammation with subsequent fibrosis. Recently, we have reported first-in-man CRP apheresis in a "high-risk" COVID-19 patient. Treatment was unfortunately clinically unsuccessful. Here, we report on successful CRP apheresis treatment in a "lower-risk" COVID-19 patient with respiratory failure. CASE REPORT A 39-year-old male patient suffering from fatigue, dyspnea, and fever for 4 days was referred to us. The patient had to be intubated. Polymerase chain reaction (PCR) analysis of a throat smear revealed SARS-CoV-2 infection. Mutation analysis revealed the VOC B. 1.1.7 variant. CRP levels were 79.2 mg/L and increased to 161.63 mg/L. Procalcitonin (PCT) levels were continuously normal (<0.5 ng/ml). Antibiotic therapy was started to avoid bacterial superinfection. CRP apheresis was performed once via central venous access. CRP levels declined from a maximum of 161.63 mg/L to 32.58 mg/L. No apheresis-associated adverse effects were observed. Subsequently, CRP plasma levels declined day by day and normalized on day 5. The patient was extubated on day 5 and discharged from the Intensive Care Unit (ICU) on day 6. A second low CRP peak (maximum 22.41 mg/L) on day 7 remained clinically inapparent. The patient was discharged in good clinical condition with a CRP level of 6.94 mg/L on day 8. CONCLUSIONS SARS-CoV-2 infection can induce an uncontrolled CRP-mediated autoimmune response of ancient immunity. In this patient, the autoimmune response was potently and successfully suppressed by early selective CRP apheresis.