🎨 Ruxolitinib Cream (JAK Inhibitor) Simulator

Interferon-Gamma and the JAK-STAT Axis in Vitiligo

Autoreactive T cells release IFN-γ that overdrives JAK-STAT signaling in skin.

• IFN-γ: Key cytokine (driven by CD8+ T cells)
• JAK1/JAK2: Kinases involved (receptor-associated)
• STAT1: Downstream factor (drives CXCL9/10)
• Melanocyte loss: Result (depigmented patches)

Overactive signaling loop

Placeholder: short note on the IFN-γ/JAK/STAT feedback loop in vitiligo lesions.

Ruxolitinib Cream (Opzelura) Mechanism of Action

Ruxolitinib competitively blocks ATP binding at JAK1 and JAK2 kinase domains.

• JAK inhibitor: Drug class (topical formulation)
• JAK1, JAK2: Targets (selective inhibition)
• Opzelura: Brand name (FDA approved 2022)
• Twice daily: Application (affected areas)

Topical kinase inhibition

Placeholder: short note on ruxolitinib absorption and local kinase blockade.

Downstream Interferon Signal Quieting

With JAK blocked, STAT1 phosphorylation and IFN-γ target genes drop.

• Reduced: STAT1 activity (less phosphorylation)
• CXCL9/10 ↓: Chemokines (less T-cell recruitment)
• Weeks: Onset (gradual suppression)
• Lower: Inflammation (lesion quieting)

Breaking the feedback loop

Placeholder: short note on reduced chemokine signaling halting T-cell attack.

Follicular Melanocyte Stem Cell Reawakening

Hair follicle melanocyte reservoirs reactivate once inflammation subsides.

• Hair follicle bulge: Reservoir site (stem cell niche)
• Reduced IFN-γ: Trigger (permissive niche)
• Outward: Migration (toward epidermis)
• Months: Timeframe (gradual repopulation)

Stem cell migration

Placeholder: short note on melanocyte stem cells repopulating epidermis.

Best-Responding Site: Facial Repigmentation Outcomes

Face and neck respond best due to dense follicular melanocyte reservoirs.

• Face: Best site (high follicle density)
• ~50%: Response rate (≥75% facial repigmentation)
• 24–52 wk: Trial duration (TRuE-V studies)
• Hands/feet: Worst site (few follicles)

Site-dependent response

Placeholder: short note on why facial skin repigments faster than acral skin.

Placeholder: short highlight on facial response being the clinical benchmark.