Does imiquimod pretreatment optimize 308-nm excimer laser (UVB) therapy in psoriasis patients?
OBJECTIVE
Psoriasis continues to be a debilitating skin disease affecting 1-3% of the United States population. Although the effectiveness of several current biologic therapies have described this pathology as a IL-23, TNF-a and Th17-mediated disease, less invasive approaches are still in use and in need of refinement. One of these is the usage of narrow band-UVB (NB-UVB) therapy to deplete specifically intra-epidermal CD3+, CD4+ and CD8+ cells to clear psoriatic plaques.


OBJECTIVE
In order to improve NB-UVB therapy, we sought to determine whether skin pre-treatment with the TLR7 agonist imiquimod (IMQ) would help increase the efficiency of the former at resolving psoriatic plaques.


METHODS
Eucerin®Original Moisturizing Lotion (topical vehicle) or Aldara®(imiquimod 5% topical cream) were applied for 5 days once daily to a maximum contiguous area of 25 cm2(5 cm × 5 cm area). Patients were provided with sachets containing 12.5 mg of imiquimod each and were instructed to apply imiquimod (I) to two psoriasis plaques (5 sachets of imiquimod allotted to each plaque). A PHAROS excimer Laser EX-308 (Ra Medical Systems, Inc. Carlsbad, CA, USA) with an output of monochromatic 308-nm light and pulse width of 20-50 ns was used for all patients. Punch biopsies of psoriatic lesions (6 mm) were taken at 4 and 48 h after final application of topical treatment with or without excimer laser treatment. Real-time quantitative RT-PCR was performed according to manufacturer's instructions and Inmunohistochemistry was used as described before.


RESULTS
Our results suggests that although IMQ seemed to activate the type I interferon pathway as previously described, its concomitant usage with NB-UVB for clearing psoriatic skin was ineffective. Although upregulation of genes MxA, GRAMD1A and DMXL2 suggested that IMQ treatment did induce skin changes in psoriasis patients, more optimal dosing of IMQ and NB-UVB might be necessary to achieve desired treatment responses.


CONCLUSIONS
The observation that psoriasis involvement was not aggravated by usage of topical IMQ was encouraging. Additional observational studies might be necessary to further tailor the combination of IMQ with NB-UVB therapy to reliably improve the psoriatic pathology.
Department of Dermatology, Case Western Reserve University, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
Joselin D
JD
Tacastacas
Department of Dermatology, Case Western Reserve University, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
Patricia
P
Oyetakin-White
Department of Dermatology, Case Western Reserve University, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
David C
DC
Soler
Department of Dermatology, Case Western Reserve University, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
Andrew
A
Young
Department of Dermatology, Case Western Reserve University, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
Sarah
S
Groft
Department of Dermatology, Case Western Reserve University, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
Kord
K
Honda
Department of Dermatology, Case Western Reserve University, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
Kevin D
KD
Cooper
Department of Dermatology, Case Western Reserve University, University Hospitals Cleveland Medical Center, Cleveland, OH, USA.
Thomas S
TS
McCormick
D000287:Administration, Topical; D000328:Adult; D000368:Aged; D000634:Aminoquinolines / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D000077271:Imiquimod; D053685:Laser Therapy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011565:Psoriasis / Q000378:metabolism* / Q000473:pathology* / Q000628:therapy*
D000634:Aminoquinolines; D000077271:Imiquimod
308-nm excimer laser; UV phototherapy; imiquimod; psoriasis