# Autoantibodies in COVID‐19 convalescent plasma donors

## TL;DR

This study examines autoantibodies in the plasma of people who recovered from COVID-19, finding that while some autoantibodies are temporarily elevated, they decline over time and do not pose long-term safety risks.

## Contribution

The study provides new insights into the temporal dynamics of autoantibodies in convalescent plasma and their implications for plasma donation safety.

## Key findings

- Autoantibodies like anti-SM and anti-SSA/Ro60 were modestly elevated in CCP samples collected within 0–60 days post symptom onset.
- Autoantibody levels declined by 60–120 days post infection and remained comparable to controls by 120–180 days.
- No significant correlation was found between neutralizing SARS-CoV-2 antibodies and autoantibody concentrations.

## Abstract

Although COVID‐19 convalescent plasma (CCP) has been successfully used to treat several viral infections, its effectiveness in neutralizing severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and its broader immunological safety remain debated. Since viral infections can trigger autoimmunity, particularly through molecular mimicry and immune dysregulation, there is growing interest in understanding whether CCP contains autoantibodies that could affect recipient safety.

In this study, we evaluated the presence of 20 different autoantibodies, along with anti‐SARS‐CoV‐2 antibodies, in plasma samples from CCP donors. Samples were collected at three time intervals following COVID‐19 symptom onset: 0–60, 60–120 and 120–180 days. Results were compared with those from healthy control plasma donors.

Several autoantibodies— anti‐Smith (anti‐SM), anti‐Sjögren syndrome antigen A, 60‐kDa isoform (anti‐SSA/Ro60), anti‐proliferating cell nuclear antigen (anti‐PCNA), anti‐Ribosomal P and anti‐ribonucleoprotein/Smith antigen complex (anti‐RNP/SM)—showed modestly elevated levels in CCP samples collected within 0–60 days post symptom onset. In the 60–120‐day period, autoantibody levels declined and approached levels observed in the control group. In the 120–180‐day period, most autoantibody levels remained comparable to control levels. Our analysis showed no significant correlations between levels of neutralizing SARS‐CoV‐2 antibodies and autoantibody concentrations nor significant differences in autoantibody profiles between donors with high and low neutralizing antibody (NAb) titres.

Our findings suggest that SARS‐CoV‐2 infection may transiently elevate certain autoantibodies in CCP donors. However, most autoantibody levels decline over time and the overall profiles do not indicate sustained autoreactivity. These results support the immunological safety of CCP, particularly when collected between 60 and 120 days post infection, and highlight the importance of timing in optimizing both efficacy and safety in plasma donation strategies.