Elicit: Downstream Cytokine Changes Post-Risankizumab

Downstream Cytokine Changes Post-Risankizumab

What downstream cytokine changes occur after risankizumab-mediated IL-23 inhibition?

I'll search for studies on cytokine pathway changes downstream of IL-23 blockade by risankizumab.

Findings from Analysis

The downstream cytokine picture from risankizumab's IL-23p19 blockade is well-characterized across multiple biomarker studies, and the changes are consistent enough to sketch with reasonable confidence.

Key Cytokine Changes

  1. IL-17 isoforms (IL-17A, IL-17C, IL-17F)

    • Most robustly reduced downstream targets.
    • The KEEPsAKE 2 biomarker substudy found significant decreases in IL-17A and IL-17C by week 4, continuing to decline through week 24. Ravishankar et al. 2023
    • A Crohn's disease phase 2b analysis showed significant reductions in plasma IL-17 and colonic IL-17A RNA. Salas et al. 2019
    • A 2019 JACI skin biopsy study extended this to demonstrate downregulated IL-17 pathway transcriptomics within 4 weeks. Visvanathan et al. 2019

  2. IL-22

    • Consistently reduced in plasma and tissue.
    • Crohn's phase 2b data showed significant decreases in circulating IL-22 protein by week 12. Salas et al. 2019
    • A study found declines in CD8+IL-22+ T cells, but baseline IL-22 levels or reduction magnitude did not predict clinical response. Salas et al. 2019

  3. IL-1β

    • Drops consistently across both psoriasis and Crohn's disease data.
    • Significant declines in plasma IL-1β and colonic IL-1β RNA were confirmed by multiple studies. Salas et al. 2019; Diotallevi et al. 2025

  4. IL-6

    • Decreases correlated with improvements in musculoskeletal disease activity (PASDAS) and skin outcomes (PASI). Ravishankar et al. 2023

  5. Th17 cell subset dynamics

    • IL-23 inhibition selectively downregulates certain IL-23 receptor-expressing T17 subsets, while increasing others. Kim et al. 2025

  6. Treg induction

    • Treg frequency increased within 16 weeks of risankizumab treatment, negatively correlating with baseline PASI.

  7. Macrophage Polarization

    • Promotion of M2-type (anti-inflammatory) macrophages at the expense of M1-type, confirmed by in vitro ELISA. Yuan et al. 2025

Overall Pattern

Across indications, the core pattern is a hub-and-spoke collapse: primary blockade of IL-23 → reduced Th17, Tc17, ILC3, γδ T cell activation → downstream suppression of IL-17A/C/F, IL-22, IL-1β, IL-6, IL-8, CCL20, and CXCL1. This evidence emerges early (by week 4 at the latest), and further studies could surface additional data on related cytokines.