(1052) Cytokine Storm Endotypes: Preclinical Models and Clinical Investigation

Introduction: Although cytokine-specific biologics are available for immune modulation of systemic inflammatory conditions, their clinical utility is limited by the inability to rapidly discriminate various inflammatory processes. Unfortunately, direct measurements inflammatory cytokines directly have not proven useful. Recently, preclinical models have demonstrated that multiple organ dysfunction syndrome (MODS) can be induced in mice by pair-wise administration of tumor necrosis factor (TNF), plus either interleukin-1 beta, IL-18, or interferon-gamma. We hypothesized that these cytokine storm models could be used to inform other biomarkers that can be used to discriminate separate cytokine storm endotypes, and that these endotypes are present in children with hyper-inflammtory syndromes.

Methods: For the preclinical models of MODS cytokines were injected retro-orbitally into C57BL/6J mice, and serial cytokine measurements were obtained from tail bleeds. Mouse cytokines were measured by enzyme-linked immunosorbent assays (ELISA) or automated microfluidic immunassays (Ella, Bio-Techne). Children admitted to Penn State Health Children’s Hospital with presumed hyper-inflammatory syndromes were enrolled and cytokines were measured by Ella.

Results: The pairwise administration of IL-1beta/TNF or IFN-gamma/TNF was near universally fatal in mice and biomarker evaluation demonstrated that TNFR1 was the best discriminator of lethal inflammation. CXCL9 was induced by IL-18/TNF and IFN-gamma/TNF, whereas IL-6 was associated with IL-1 signaling activation. The measurement of four cytokines (CXCL9, IL-6, IL-18 and TNFR1) was used to assess the cytokine storm profile in children with various inflammatory conditions. Latent class analysis determined that 39% (11 of 28) of children had cytokine storm. Children with cytokine storm demonstrated a 28-day mortality of 36% compared to 0% without cytokine storm.

Conclusions: The presence of hyper-inflammation is associated with poor outcomes in children. This four-biomarker panel may provide insight into the presence of cytokine storm, and ultimately provide prognostic and predictive enrichment for future studies. Future studies with adequate power are needed to validate this panel.