# The Seraph 100® Microbind Affinity Blood Filter Does Not Alter Levels of Circulating or Mucosal Antibodies in Critical COVID-19 Patients

## TL;DR

This study found that using the Seraph 100® blood filter in critically ill COVID-19 patients does not change their antibody levels in the blood or in the lungs.

## Contribution

The study provides new evidence that the Seraph 100® filter does not affect antibody levels in ICU patients with severe COVID-19.

## Key findings

- Seraph 100® treatment did not alter serum IgG and IgA levels against SARS-CoV-2.
- Mucosal antibody levels in tracheal aspirates remained unchanged after Seraph 100® use.
- Direct filter impact on circulating antibodies was not observed in pre- and post-filter samples.

## Abstract

PURIFY-OBS-1 is an observational study evaluating the safety and efficacy of Seraph 100® Microbind Affinity Blood Filter (Seraph 100) use for COVID-19 patients with respiratory failure admitted to the intensive care unit (ICU). The Seraph 100 is a hemoperfusion device containing heparin-coated beads that can bind to, and reduce levels of, some circulating pathogens and inflammatory molecules. This study evaluated whether treatment with the Seraph 100 affected circulating and mucosal antibody levels in critically ill COVID-19 subjects. SARS-CoV-2 anti-spike and anti-nucleocapsid IgG and IgA levels in serum were evaluated at enrollment and on days 1, 4, 7, and 28 after Seraph 100 application, while anti-spike and nucleocapsid IgG, IgA, and secretory IgA levels in tracheal aspirates were evaluated at enrollment and on days 1, 2, 3, 7, and 28. Serum samples were also collected from the pre- and post-filter lines at 1 and 4 h following Seraph 100 application to evaluate the direct impact of the filter on circulating antibody levels. Treatment with the Seraph 100 did not alter the levels of circulating or mucosal antibodies in critically ill COVID-19 subjects admitted to the ICU.