Evidence Hub

C1-esterase Inhibitor Treatment is Associated with Immune and Vascular Pathway Modulation in PASC with Neurological Symptoms: Longitudinal Plasma Proteomics

Orr N, Collins M, Novak S, Melamed I, Steinman L

Cellular and molecular neurobiology, 2026

10 participants

Abstract

Post-acute sequelae of SARS-CoV-2 infection (PASC), particularly neurological manifestations, remain a significant therapeutic challenge, likely driven by persistent inflammation, immune dysregulation, and endothelial dysfunction. In a randomized, double-blind, placebo-controlled crossover trial, 10 patients with post-COVID-19 neurological symptoms received C1-esterase inhibitor (C1-INH; RUCONEST®) or placebo over two eight-week phases. Longitudinal plasma proteomics (SomaScan®) profiled molecular dynamics during and after C1-INH treatment. C1-INH administration was associated with distinct, phase-specific proteomic signatures, including lower levels of inflammatory-associated proteins such as CRP and IL-6, increased levels of neuroimmune and endothelial repair proteins (Neuropilin-2, CD83, C1QTNF5), and modulation of bradykinin-kinin and extracellular matrix pathways. These molecular shifts were evaluated in relation to clinical change scores during the active treatment windows. Several proteomic changes were observed at timepoint 26 after treatment cessation, describing candidate post-treatment molecular trajectories. In conclusion, these results provide exploratory mechanistic insights and support the need for validation in larger, prospective cohorts. Together, these findings prioritize immune and vascular pathways for further investigation in PASC and may have relevance to other post-infectious neuroimmune conditions.

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 10 participants or records.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free