Growing evidence indicates that autoantibodies may drive symptoms in a subset of people
with long COVID, as demonstrated by symptom transfer to mice following administration of
IgG from affected patients. This provides a strong rationale for targeted immunotherapy
aimed at removing pathogenic antibodies. Immunoadsorption is a well-established method to
reduce circulating IgG, but studies suggest that only a specific subgroup of patients
benefits.

Using HuProt autoantibody microarray technology, we identified several autoantibodies
uniquely present in long COVID patients compared with healthy controls. We subsequently
developed and validated a disease-specific Luminex multiplex immunoassay to detect this
autoimmune phenotype. This study will use these findings as a novel selection method of
identifying long COVID patients with pathogenic IgG, thereby enriching the population
most likely to benefit from immunoadsorption therapy.

This biomarker-guided personalized medicine approach could enhance treatment efficacy and
advances long COVID therapeutic strategies. Additionally, the placebo-controlled and
double blinded design will be needed to evaluate the true potential of autoantibodies
adsorption therapy in long COVID. This study can add to our understanding on the role of
autoantibodies in the pathogenesis of long COVID and could help in the development of
precision-based immunotherapy for patients such as immunoadsorption.