Why 311nm Narrowband UVB
Narrowband UVB isolates the most therapeutic wavelength band.
- 311 nm: Peak wavelength (narrowband UVB (TL-01))
- 280–320nm: Broadband range (older UVB devices)
- Lower: Erythema efficiency (vs broadband UVB)
- ~70%: Clearance rate (typical psoriasis response)
Spectral targeting of the therapeutic band
311nm targets pathology while sparing surrounding tissue.
Placeholder: narrowband lamps reduce burn risk versus broadband UVB.
Inducing Apoptosis in Pathogenic T-Cells
UVB photons damage DNA in activated dermal T-lymphocytes.
- Th1/Th17: Target cells (psoriatic T-lymphocytes)
- DNA damage: Mechanism (pyrimidine dimer formation)
- ~2–4 wks: Onset (sessions to clinical effect)
- IL-17, IL-23: Cytokine drop (reduced signaling)
Photoimmunology of T-cell depletion
Repeated exposure depletes pathogenic skin-infiltrating T-cells.
Placeholder: apoptosis reduces local inflammatory cytokine load.
Restoring Normal Epidermal Turnover
Keratinocyte division slows from psoriatic to normal rate.
- ~4 days: Psoriatic turnover (vs 28 days normal skin)
- ~28 days: Target turnover (normalized epidermal cycle)
- ↓ over weeks: Plaque thickness (scale and thickness reduce)
- Cytokine drop: Driven by (from T-cell suppression)
Coupling immune signal to keratinocyte cycle
Reduced cytokines slow keratinocyte hyperproliferation.
Placeholder: normalization lags behind immune suppression by design.
Titrating to the Minimal Erythema Dose
Dose is escalated just below the erythema threshold.
- Pre-treatment: MED test (individualized dose baseline)
- 10–20%: Typical increment (per session escalation)
- Minimal pink: Erythema target (sub-blistering threshold)
- I–VI scale: Skin phototype (adjusts starting dose)
Balancing efficacy against burn risk
Dose titration maximizes benefit while limiting erythema.
Placeholder: overshooting MED risks burns and treatment pauses.
Cumulative Dose and Long-Term Skin Cancer Risk
Lifetime UVB exposure is tracked to manage cancer risk.
- Cumulative J/cm²: Risk factor (lifetime dose tracking)
- 20–30 sessions: Typical course (per treatment cycle)
- Annual skin exam: Monitoring (long-term surveillance)
- Lower: Risk vs PUVA (compared to psoralen UVA)
Managing lifetime phototherapy exposure
Cumulative dose logs inform long-term treatment limits.
Placeholder: narrowband UVB carries lower carcinogenic risk than PUVA.