Distinct T cell signatures are associated with Staphylococcus aureus skin infection in pediatric atopic dermatitis.

Atopic dermatitis (AD) is an inflammatory skin condition with a childhood prevalence of up to 25%. Microbial dysbiosis is characteristic of AD, with Staphylococcus aureus the most frequent pathogen associated with disease flares and increasingly implicated in disease pathogenesis. Therapeutics to mitigate the effects of S. aureus have had limited efficacy and S. aureus-associated temporal disease flares are synonymous with AD. An alternative approach is an anti-S. aureus vaccine, tailored to AD. Experimental vaccines have highlighted the importance of T cells in conferring protective anti-S. aureus responses; however, correlates of T cell immunity against S. aureus in AD have not been identified. We identify a systemic and cutaneous immunological signature associated with S. aureus skin infection (ADS.aureus) in a pediatric AD cohort, using a combined Bayesian multinomial analysis. ADS.aureus was most highly associated with elevated cutaneous chemokines IP10 and TARC, which preferentially direct Th1 and Th2 cells to skin. Systemic CD4+ and CD8+ T cells, except for Th2 cells, were suppressed in ADS.aureus, particularly circulating Th1, memory IL-10+ T cells, and skin-homing memory Th17 cells. Systemic γδ T cell expansion in ADS.aureus was also observed. This study suggests that augmentation of protective T cell subsets is a potential therapeutic strategy in the management of S. aureus in AD.

Artificial White Light vs Daylight Photodynamic Therapy for Actinic Keratoses: A Randomized Clinical Trial.

IMPORTANCE: Daylight photodynamic therapy using topical methyl 5-aminolevulinic acid (MAL) for actinic keratoses (AKs) is as effective as conventional photodynamic therapy but has the advantage of being almost pain free. Daylight photodynamic therapy, however, requires dry and warm weather conditions. OBJECTIVE: To establish if topical MAL photodynamic therapy using a white light light-emitting diode (LED) lamp is as effective and well-tolerated as daylight photodynamic therapy for the treatment of AKs. DESIGN, SETTING, AND PARTICIPANTS: Overall, 22 men with significant photodamage and a high number of AKs were enrolled in this prospective, randomized, single-blind study, employing a split-scalp design, comparing the effectiveness and adverse effects of daylight photodynamic therapy and artificial white light (AWL) LED photodynamic therapy for the treatment of AKs on the forehead and scalp. Organ transplant recipients were excluded. Patients were treated and evaluated at an academic tertiary referral dermatology center. Treatment lasted from April 2014 to July 2014 and follow-up visits occurred for 9 months posttreatment. INTERVENTIONS: Two symmetrical treatment fields were defined and AKs counted, mapped, and photographed at baseline, 1, 3, 6, and 9 months. Patients had half of their scalp treated with daylight photodynamic therapy and the other half treated with AWL photodynamic therapy 1 week apart and randomly allocated. MAL was applied, and treatment commenced 30 minutes later and lasted 2 hours. Irradiance, illuminance, and light spectra measurements were performed. The integrated dose in J/cm2 was measured. The effective light dose, weighted to the absorption spectrum for protoporphyrin IX, was calculated. MAIN OUTCOMES AND MEASURES: The primary end point was the reduction in total AK count per treatment field. Secondary end points included adverse effects and patient satisfaction. RESULTS: We enrolled 22 men with a median age of 72 years (range, 47-85 years) at baseline, the total (median of AKs per field) were 469 (20.5) for the DPDT group and 496 (20.5) for the AWLPDT group (P = .34). The median number and percentage of reduction in AKs per field were 12 and 62.3% for DPDT and 14 and 67.7% for AWLPDT at 1 month (P = .21 and P = .13, respectively). There was no significant difference in the reduction percentage of AKs for either treatment at 1, 3, and 6 months. At 9 months, the median number and percentage of reduction in AKs per field was 9.0 and 48.4% for DPDT and 12.0 and 64.4% for AWLPDT (P = .13 and P = .05, respectively). Pain was reported by 14 patients with DPDT and 16 patients with AWLPDT (median maximum score [out of 100], 4 vs 6; P = .51). Moderate erythema was reported by 9 patients after DPDT and 14 patients after AWLPDT. On a scale of 0 (intolerable) to 10 (very tolerable) patients rated DPDT as 9.5 and AWLPDT as 9 (P = .37). CONCLUSIONS AND RELEVANCE: Photodynamic therapy using an AWL source was as effective and well-tolerated as daylight photodynamic therapy. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT02520700.