1.
Longitudinal Study of the Psoriasis-Associated Skin Microbiome during Therapy with Ustekinumab in a Randomized Phase 3b Clinical Trial.
Loesche, MA, Farahi, K, Capone, K, Fakharzadeh, S, Blauvelt, A, Duffin, KC, DePrimo, SE, Muñoz-Elías, EJ, Brodmerkel, C, Dasgupta, B, et al
The Journal of investigative dermatology. 2018;138(9):1973-1981
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Chronic plaque psoriasis is an immune-mediated disease of the skin and joints. A growing appreciation of the role of the innate immune system in psoriasis pathogenesis stems from the prominent role of inflammatory cytokines and cells associated with innate immunity in the disease and associations observed between psoriasis and genetic variations involved in innate immunity. The aim of this study was to assess changes of the skin microbiome in the setting of a longitudinal phase 3b study of patients receiving up to 2 years of ustekinumab therapy. Results show that prior to treatment, there were minor, body-site specific differences in microbial diversity and composition when comparing lesional with non-lesional skin. Microbial heterogeneity was greater in lesional skin than non-lesional skin. During ustekinumab treatment, the composition of microbiota diverged further between lesional and non-lesional skin across body sites. The divergence observed between lesional and non-lesional skin during ustekinumab treatment varied by body site. Authors conclude that their findings may help inform future study design and it may also have medically relevant implications for diagnostics and therapeutics involving the skin microbiome.
Abstract
Plaque psoriasis, a chronic inflammatory disease primarily affecting the skin, is thought to have a multifactorial etiology, including innate immune system dysregulation, environmental triggers, and genetic susceptibility. We sought to further understand the role of skin microbiota in psoriasis pathogenesis, as well as their response to therapy. We systematically analyzed dynamic microbiota colonizing psoriasis lesions and adjacent nonlesional skin in 114 patients prior to and during ustekinumab treatment in a phase 3b clinical trial. By sequencing the bacterial 16S ribosomal RNA gene from skin swab samples obtained at six anatomical sites, we identified minor, site-specific differences in microbial diversity and composition between pretreatment lesional and nonlesional skin. During therapy, microbial communities within lesional and nonlesional skin diverged, and body-site dispersion increased, reflecting microbial skin site-specificity. Microbiota demonstrated greater pretreatment heterogeneity in psoriatic lesions than in nonlesional skin, and variance increased as treatment progressed. Microbiota colonizing recurrent lesions did not overlap with pretreatment lesional microbiota, suggesting colonization patterns varied between initial and recurrent psoriatic lesions. While plaque psoriasis does not appear to be associated with specific microbes and/or microbial diversity, this large dataset provides insight into microbial variation associated with (i) disease in different body locations, (ii) initial versus recurrent lesions, and (iii) anti-IL12/23 therapy.
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Randomized trial of peanut consumption in infants at risk for peanut allergy.
Du Toit, G, Roberts, G, Sayre, PH, Bahnson, HT, Radulovic, S, Santos, AF, Brough, HA, Phippard, D, Basting, M, Feeney, M, et al
The New England journal of medicine. 2015;372(9):803-13
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Children with peanut allergies are at a higher risk of death and anaphylaxis. This randomised, open-label, controlled study investigated whether reducing peanut exposure or eliminating peanuts is a better strategy to prevent peanut allergy development. Six hundred and forty infants between the ages of four months and eleven months old were randomly assigned to different cohorts depending on whether they had a pre-existing sensitivity to peanut extract. The study also assessed the proportion of infants with peanut allergies at 60 months. The introduction of peanuts at an early age significantly reduced peanut allergies in infants at high risk. Those who consumed peanuts had elevated peanut-specific IgG4 antibody levels whereas those who avoided peanuts had elevated peanut-specific IgE antibody levels. At the age of sixty months, the proportion of infants in the intention-to-treat group that developed peanut allergy was higher in the infants who avoided peanuts than in those who consumed them. As this study only included low-risk infants, future robust studies will be required to prove the benefits of peanuts’ early introduction. These results can be used by healthcare professionals to develop potential strategies to reduce the prevalence of peanut allergy in children.
Abstract
BACKGROUND The prevalence of peanut allergy among children in Western countries has doubled in the past 10 years, and peanut allergy is becoming apparent in Africa and Asia. We evaluated strategies of peanut consumption and avoidance to determine which strategy is most effective in preventing the development of peanut allergy in infants at high risk for the allergy. METHODS We randomly assigned 640 infants with severe eczema, egg allergy, or both to consume or avoid peanuts until 60 months of age. Participants, who were at least 4 months but younger than 11 months of age at randomization, were assigned to separate study cohorts on the basis of preexisting sensitivity to peanut extract, which was determined with the use of a skin-prick test--one consisting of participants with no measurable wheal after testing and the other consisting of those with a wheal measuring 1 to 4 mm in diameter. The primary outcome, which was assessed independently in each cohort, was the proportion of participants with peanut allergy at 60 months of age. RESULTS Among the 530 infants in the intention-to-treat population who initially had negative results on the skin-prick test, the prevalence of peanut allergy at 60 months of age was 13.7% in the avoidance group and 1.9% in the consumption group (P<0.001). Among the 98 participants in the intention-to-treat population who initially had positive test results, the prevalence of peanut allergy was 35.3% in the avoidance group and 10.6% in the consumption group (P=0.004). There was no significant between-group difference in the incidence of serious adverse events. Increases in levels of peanut-specific IgG4 antibody occurred predominantly in the consumption group; a greater percentage of participants in the avoidance group had elevated titers of peanut-specific IgE antibody. A larger wheal on the skin-prick test and a lower ratio of peanut-specific IgG4:IgE were associated with peanut allergy. CONCLUSIONS The early introduction of peanuts significantly decreased the frequency of the development of peanut allergy among children at high risk for this allergy and modulated immune responses to peanuts. (Funded by the National Institute of Allergy and Infectious Diseases and others; ClinicalTrials.gov number, NCT00329784.).