# Hyperferritinemia screening to aid identification and differentiation of patients with hyperinflammatory disorders

## TL;DR

This study shows how measuring high ferritin levels can help identify and distinguish patients with severe inflammatory diseases, enabling early sample collection and better understanding of these conditions.

## Contribution

A real-time alert system for hyperferritinemia was implemented to classify patients and collect early samples, revealing new biomarker patterns in hyperinflammatory disorders.

## Key findings

- 30.5% of patients with high ferritin had inflammatory hyperferritinemia (IHF), with higher ferritin levels compared to hemoglobinopathy or transplant patients.
- Total IL-18 levels were highly elevated in patients with Stills Disease and/or Macrophage Activation Syndrome.
- Hyperferritinemic sepsis patients showed reduced ANGPT1 and VEGFR2 proteins compared to non-sepsis controls.

## Abstract

High ferritin is an important and sensitive biomarker for hemophagocytic lymphohistiocytosis (HLH), a diverse and deadly group of cytokine storm syndromes. Early action to prevent immunopathology in HLH often includes empiric immunomodulation, which can complicate etiologic work-up and prevent collection of early/pre-treatment research samples. To address this, we instituted an alert system where serum ferritin > 1000ng/mL triggered real-time chart review, assessment of whether the value reflected “inflammatory hyperferritnemia (IHF)”, and biobanking of remnant samples from consenting IHF patients. We extracted relevant clinical data; periodically measured serum total IL-18, IL-18 binding protein (IL-18BP), and CXCL9; retrospectively classified patients by etiology into infectious, rheumatic, or immune dysregulation; and subjected a subgroup of samples to a 96-analyte biomarker screen. 180 patients were identified, 30.5% of which had IHF. Maximum ferritin levels were significantly higher in patients with IHF than with either hemoglobinopathy or transplant, and highly elevated total IL-18 levels were distinctive to patients with Stills Disease and/or Macrophage Activation Syndrome (MAS). Multi-analyte analysis showed elevation in proteins associated with cytotoxic lymphocytes in all IHF samples when compared to healthy controls and depression of proteins such as ANGPT1 and VEGFR2 in samples from hyperferritinemic sepsis patients relative to non-sepsis controls. This single-center, real-time IFH screen proved feasible and efficient, validated prior observations about the specificity of IL-18, enabled early sample collection from a complex population, suggested a unique vascular biomarker signature in hyperferritinemic sepsis, and expanded our understanding of IHF heterogeneity.