Tali Czarnowicki

Severe atopic dermatitis is characterized by selective expansion of circulating TH2/TC2 and TH22/TC22, but not TH17/TC17, cells within the skin-homing T-cell population

BACKGROUND Past studies of blood T-cell phenotyping in patients with atopic dermatitis (AD) have provided controversial results and were mostly performed before the identification of TH9, TH17, and TH22 T-cell populations in human subjects. OBJECTIVE We sought to quantify TH1, TH2, TH9, TH17, and TH22 T-cell populations and corresponding CD8(+) T-cell subsets in both cutaneous lymphocyte antigen (CLA)-positive and CLA(-) T-cell subsets in patients with AD and control subjects. METHODS We studied 42 adults with severe AD (mean SCORAD score, 65) and 25 healthy subjects using an 11-color flow cytometric antibody panel. Frequencies of IFN-γ-, IL-22-, IL-13-, IL-17-, and IL-9-producing CD4(+) and CD8(+) T cells were compared in CLA(-) and CLA(+) populations. RESULTS We measured increased TH2/TC2/IL-13(+) and TH22/TC22/IL-22(+) populations (P < .1) in patients with severe AD versus control subjects, with significant differences in CLA(+) T-cell numbers (P < .01). A significantly lower frequency of CLA(+) IFN-γ-producing cells was observed in patients with AD, with no significant differences in CLA(-) T-cell numbers. The CLA(+) TH1/TH2 and TC1/TC2 ratio was highly imbalanced in patients with AD (10 vs 3 [P = .005] and 19 vs 7 [P < .001], respectively). Positive correlations were found between frequencies of IL-13- and IL-22-producing CD4(+) and CD8(+) T cells (r = 0.5 and 0.8, respectively; P < .0001), and frequencies of IL-13-producing CLA(+) cells were also correlated with IgE levels and SCORAD scores. Patients with AD with skin infections had higher CD4(+) IL-22(+) and IL-17(+) cell frequencies, which were highly significant among CLA(-) cells (IL-22: 3.7 vs 1.7 [P < .001] and IL-17: 1.7 vs 0.6 [P < .001]), with less significant effects among CLA(+) T cells (IL-22: 11 vs 7.5, P = .04). CONCLUSIONS Severe AD is accompanied by expansion of skin-homing TH2/TC2 and TH22/TC22 subsets with lower TH1/TC1 frequencies. These data create a critical basis for studying alterations in immune activation in adults and pediatric patients with AD.

Cyclosporine in patients with atopic dermatitis modulates activated inflammatory pathways and reverses epidermal pathology.

BACKGROUND Atopic dermatitis (AD) is the most common inflammatory disease. Evolving disease models link changes in epidermal growth and differentiation to T(H)2/T(H)22 cytokine activation. However, these models have not been tested by in vivo suppression of T-cell cytokines. Cyclosporine (CsA) is an immunosuppressant that is highly effective for severe disease, but its mechanism in AD skin lesions has not been studied. OBJECTIVE We sought to establish the ability of a systemic immunosuppressant to modulate immune and epidermal alterations that form the pathogenic disease phenotype and to correlate changes with clinical improvement. METHODS CsAs effects on AD skin pathology were evaluated by using gene expression and immunohistochemistry studies in baseline, week 2, and week 12 lesional and nonlesional biopsy specimens from 19 patients treated with 5 mg/kg/d CsA for 12 weeks. RESULTS After 2 and 12 weeks of treatment, we observed significant reductions of 51% and 72%, respectively, in SCORAD scores. Clinical improvements were associated with significant gene expression changes in lesional but also nonlesional skin, particularly reductions in levels of T(H)2-, T(H)22-, and some T(H)17-related molecules (ie, IL-13, IL-22, CCL17, S100As, and elafin/peptidase inhibitor 3), and modulation of epidermal hyperplasia and differentiation measures. CONCLUSIONS This is the first study that establishes a relationship between cytokine activation and molecular epidermal alterations, as well as correlations between disease biomarkers in the skin and clinical improvement. The reversal of the molecular phenotype with CsA and the associated biomarkers can serve as a reference for the successful modulation of tissue inflammation with specific immune antagonists in future studies, contributing to the understanding of the specific cytokines involved in epidermal pathology.

Skin Barrier and Immune Dysregulation in Atopic Dermatitis: An Evolving Story with Important Clinical Implications

Atopic dermatitis is the most common chronic inflammatory skin disease. Its pathogenesis combines barrier defects, immune dysregulation, and increased skin infections; however, the relative contribution of each of these components is yet to be determined. Uninvolved atopic dermatitis skin also displays broad immune and barrier abnormalities, which highlights a role for proactive treatment strategy. The residual disease genomic profile that accompanies clinical resolution provides further support for proactive treatment approaches. Although intrinsic and extrinsic atopic dermatitis subtypes share a common clinical phenotype, they show some important differences in their Th22/Th17 cytokine profile, which opens the door for personalized specific therapeutics for each disease category.

Diverse activation and differentiation of multiple B-cell subsets in patients with atopic dermatitis but not in patients with psoriasis

BACKGROUND Atopic dermatitis (AD) and psoriasis pathogeneses involve skin barrier impairment and immune dysregulation; however, the contribution of B-cell imbalances to these diseases has not yet been determined. OBJECTIVE We sought to quantify B-cell populations and antibody-secreting cells in the blood of patients with AD, patients with psoriasis, and control subjects. METHODS We studied 34 adults with moderate-to-severe AD (mean SCORAD score, 65), 24 patients with psoriasis (mean Psoriasis Area and Severity Index score, 16), and 27 healthy subjects using an 11-color flow cytometric antibody panel. IgD/CD27 and CD24/CD38 core gating systems were used to determine frequencies of plasmablasts and naive, memory, transitional, and activated B cells. RESULTS We measured increased CD19(+)CD20(+) B-cell counts in the skin and blood of patients with AD (P < .01). Significantly higher frequencies of chronically activated CD27(+) memory and nonswitched memory B cells were observed in patients with AD (P < .05), with lower values of double-negative populations (4% for patients with AD vs. 7% for patients with psoriasis [P = .001] and 6% for control subjects [P = .02]). CD23 expression was highest in patients with AD and correlated with IgE levels (P < .01) and disease severity (r = 0.6, P = .0002). Plasmablast frequencies and IgE expression were highest in all memory subsets of patients with AD (P < .01). Finally, CD19(+)CD24(++)CD38(++) transitional and CD19(+)CD24(-)CD38(-) new memory B-cell counts were higher in patients with AD versus those in patients with psoriasis (2.8% vs. 1.4% [P = .001] and 9.2% vs. 5.7% [P = .02], respectively). CONCLUSIONS AD is accompanied by systemic expansion of transitional and chronically activated CD27(+) memory, plasmablast, and IgE-expressing memory subsets. These data create a critical basis for the future understanding of this debilitating skin disease.

Patients with atopic dermatitis have attenuated and distinct contact hypersensitivity responses to common allergens in skin

BACKGROUND Atopic dermatitis (AD) is the most common inflammatory disease. The prevalence of allergic contact dermatitis to allergens (eg, fragrance) is higher in patients with AD, despite a trend toward weaker clinical allergic contact dermatitis reactions. The role of the AD skin phenotype in modulating allergic sensitization to common sensitizers has not been evaluated. OBJECTIVE We sought to investigate whether patients with AD have altered tissue immune responses on allergen challenge. METHODS Gene expression and immunohistochemistry studies were performed on biopsy specimens from 10 patients with AD and 14 patients without AD patch tested with common contact allergens (nickel, fragrance, and rubber). RESULTS Although 1085 differentially expressed genes (DEGs) were commonly modulated in patch-tested skin from patients with AD and patients without AD versus control skin, 1185 DEGs were uniquely altered in skin from patients without AD, and only 246 DEGs were altered in skin from patients with AD. Although many inflammatory products (ie, matrix metalloproteinase 12/matrix metalloproteinase 1/S100A9) were upregulated in both groups, higher-magnitude changes and upregulation of interferon responses were evident only in the non-AD group. Stratification by allergen showed decreased expression of immune, TH1-subset, and TH2-subset genes in nickel-related AD responses, with increased TH17/IL-23 skewing. Rubber/fragrance showed similar trends of lesser magnitude. Negative regulators showed higher expression in patients with AD. CONCLUSIONS Through contact sensitization, our study offers new insights into AD. Allergic immune reactions were globally attenuated and differentially polarized in patients with AD, with significant decreases in levels of TH1 products, some increases in levels of TH17 products, and inconsistent upregulation in levels of TH2 products. The overall hyporesponsiveness in skin from patients with background AD might be explained by baseline immune abnormalities, such as increased TH2, TH17, and negative regulator levels compared with those seen in non-AD skin.

Alterations in B-cell subsets in pediatric patients with early atopic dermatitis

Background B cells undergo maturation and class‐switching in response to antigen exposure and T‐cell help. Early B‐cell differentiation has not been defined in patients with early‐onset atopic dermatitis (AD). Objective We sought to define the frequency of B‐cell subsets associated with progressive B‐cell maturation and IgE class‐switching. Methods We studied 27 children and 34 adults with moderate‐to‐severe AD (mean SCORAD score, 55 and 65, respectively) and age‐matched control subjects (15 children and 27 adults). IgD/CD27 and CD24/CD38 core gating systems and an 11‐color flow cytometric panel were used to determine the frequencies of circulating B‐cell subsets. Serum total and allergen‐specific IgE (sIgE) levels were measured by using ImmunoCAP. Results Compared with adults, children showed T‐cell predominance in the skin. Circulating CD19+CD20+ B‐cell counts were lower in patients with pediatric AD than in control subjects (24% vs 33%, P = .04), whereas CD3+ T‐cell counts were higher (62% vs 52%, P = .05). A decreased B‐cell/T‐cell lymphocyte ratio with age was observed only in pediatric control subjects (r = −0.48, P = .07). In pediatric patients with AD, a positive correlation was observed between B‐cell/T‐cell ratio and nonswitched memory B‐cell counts (r = 0.42, P = .03). Higher frequencies of positive sIgE levels were seen in pediatric patients with AD (P < .0001). Diverse sIgE levels correlated with SCORAD scores and age of pediatric patients with AD (P < .01). Positive correlations were observed between activated B‐cell and memory T‐cell counts (P < .02). In patients with AD, IgE sensitization to most allergens clustered with age, TH1, TH2, total IgE levels, and B‐cell memory subsets. Conclusions Peripheral B and T cells are altered in pediatric patients with early AD, but T cells predominate in skin lesions.

An Update on the Pathophysiology of Atopic Dermatitis

Atopic dermatitis (AD) is increasingly recognized as a complex, inflammatory skin disease involving interplay of multiple elements. This article notes key advances in understanding of immune dysregulation, skin barrier dysfunction, environmental, genetic, and microbial influences orchestrating disease pathogenesis, and the relevance of therapeutic interventions in each area. Accumulating evidence and the discovery of new T-cell subsets has matured AD as a multiple-cytokine-axes-driven disorder, evolved from the widely held belief of it being a biphasic Th1/Th2 disease. These new insights have led to active trials testing multiple, targeted therapeutics with better efficacy and safety-profiles.

Accelerated T-cell activation and differentiation of polar subsets characterizes early atopic dermatitis development

To the Editor: Infancy is a crucial period for immune development. Cellular immune responses are immature at birth, with decreased natural killer cell activity and regulatory responses. Little is known about T-cell activation and subset differentiation in patients with atopic dermatitis (AD) during disease initiation in the first years of life. To study early AD development, blood was obtained from 29 infants and toddlers aged 0 to 3 years (mean, 14.5 months; SCORAD score: range, 21-84; mean, 54) with moderate-tosevere AD, 13 children aged 3 to 6 years with infancy-onset and persistent disease (mean, 57.1 months; SCORAD score: range, 36-73; mean, 53), and their respective age-matched control subjects (demographic data are shown in Table E1 in this article’s Online Repository at www.jacionline.org). T-cell surface markers and intracellular flow cytometric panels were generated (see the Methods section in this article’s Online Repository at www.jacionline.org) to measure polar differentiation and activated CD4/CD8 T-cell frequencies in central memory T (TCM/CCR7 CD45RO) cell and effector memory T (TEM/CCR7 CD45RO) cell subsets in skinhoming/cutaneous lymphocyte antigen (CLA) and CLA subsets. Circulating CLA T cells constitute blood biomarkers for skin inflammation. TCM and TEM cell populations were further characterized by mid (inducible costimulator [ICOS]) and late (HLA-DR) activation markers. Data were analyzed with the Student t test and Pearson correlation coefficient to correlate variables. P values of less than .05 were considered significant. At birth, most T cells are naive. Antigen exposure induces T cells to differentiate into TEM, TCM, and terminally differentiated effector memory (TEMRA/CCR7 CD45RO) cells. In both control subjects and patients with AD, CD4 naive cell counts progressively decreased (control subjects: r520.62, P5 .002; patients with AD: r520.56, P < .001; Fig 1, A and B) parallel to increases in TCM/TEM cell subsets (P< .05; Fig 1,C-F). Uniquely in patients with AD, numbers of TEM (but not TCM) cells, which have rapid effector function, were higher in 3to 6-year-old patients with AD versus those in 0to 3-year-old patients with AD (14.1% vs 4.9%, P 5 .02; Fig 1, G and H). More CLA TCM cells were present in 3to 6-year-old patients with AD (but not 0to 3-year-old patients with AD) versus control subjects (28.0% vs 13.9%, P 5 .004; Fig 1, I). In contrast, the CLA/TEM cell subset was higher in both the 0to 3-year-old (40.7% vs 28.5%, P 5 .02; Fig 1, J) and 3to 6-year-old (42.9% vs 25.1%, P 5 .003; Fig 1, J) groups. Opposite trends were observed in the CLA populations (Fig 1, K and L). Differences were not observed between the 2 AD cohorts (0-3/3-6 year olds; P > .16; Fig 1, I-L). Numbers of TEMRA cells, the most differentiated effector memory subset, positively correlated with age only in control subjects (r 5 0.5, P 5 .01; Fig 1, M and N), likely based on their earlier differentiation in patients with AD (0-3 years old: 5.5% vs 3.6%, P 5 .02; Fig 1, O). These data demonstrate increased effector T-cell differentiation at AD initiation exclusively in the skin-homing compartment. Past studies showed fewer CD8 than CD4T cells in infants. Consistently, neither patients with AD nor control subjects showed significant increases in CD8 TCM/TEM cell counts (P > .14; see Fig E1 in this article’s Online Repository at www.jacionline.org), supporting our recent demonstration that the TH1/TH2 imbalance in early AD is CD4 1 selective, with CD8 T cells playing a lesser role in initial AD development. We recently reported that TCM/TEM ICOS activation, which also stimulates TH2 expansion and IgE switching, is greater in children with AD. Indeed, ICOS activation was greater in younger (0to 3 years old) children with AD, particularly in CLA cells (TCM cells: 7.3% vs 4.1%, P 5 .02; TEM cells: 18.6% vs 9.6%, P 5 .02; see Fig E2, A and B, in this article’s Online Repository at www.jacionline.org), with CLA differences more obvious in the 3to 6-year-old group (see Fig E2, C and D). Chronological decreases of memory subset activation were observed in both groups but reached significance only in control subjects (P < .05; see Fig E2, E-L). Ongoing TCM ICOS activation in patients with early AD indicates maintenance of a large lymph node T-cell reservoir, whereas early high numbers of TEM cells are probably crucial for disease initiation. No differences in HLA-DR chronic activation were seen between control subjects and patients with AD (P > .2, data not shown). However, the age-related increases exclusively in patients with AD (TCM cells: CLA 1 r 5 0.4, P 5 .02 and CLA r 5 0.47, P 5 .004; see Fig E2, M-P) suggest a later contribution of HLA-DR to AD. Skin residence could explain why chronological HLA-DR increases in blood were not significant for TEM cells (P > .13, data not shown). Because activation of memory cells precedes T-cell differentiation, we next studied polar subsets. The smaller skin-homing TH1 subset in patients with AD versus control subjects was particularly prominent in patients with AD aged 0 to 3 years (6.8% vs 11.6%, P 5 .009; Fig 2, A). As previously reported, significant increases in IFN-gCLA cells were observed in older versus younger control subjects (20.1% vs 11.6%, P 5 .04; Fig 2, A) but not in patients with AD (P 5 0.08; Fig 2, A). These changes were not seen in the CLA subset (Fig 2, B), emphasizing the role of inappropriate TH1 developmental delay exclusively among the skin-homing compartment in early AD. Conversely, IL-13 levels were significantly higher in the younger AD group in both CLA (10.0% vs 1.9%, P < .001; Fig 2, C) and CLA (1.1% vs 0.4%, P 5 .008; Fig 2, D) subsets, without further increases in patients with AD aged 3 to 6 years (P>.29; Fig 2,C andD), supporting the frequent concurrence of noncutaneous atopic manifestations beginning early in AD. These results underscore the role of primary CLA TH1/TH2 cytokine dysregulation in AD initiation, which is further demonstrated by a low TH1/TH2 ratio in patients with AD aged 0 to 3 years versus control subjects (CLA: 1.7% vs 8%, P 5 .001 and CLA: 7.5% vs 18.5%, P 5 .003; Fig 2, E and F). Children with AD demonstrated ‘‘normalization’’ of the TH1/TH2 ratio with age only in the

Circulating CLA+ T‐cells in atopic dermatitis and their possible role as peripheral biomarkers

Cutaneous lymphocyte‐associated antigen (CLA+) T cells are specialized for skin homing and represent the main T‐cell population in atopic dermatitis (AD) lesions. CLA+ is expressed on the surface of circulating CD45RO+ memory T cells and most skin‐infiltrating T cells. Mechanistic studies and thus treatment advancements are limited by the need of large number of skin biopsies. Circulating CLA+ T cells may be a reliable surrogate marker of the inflammatory events occurring in the skin, and thus, the evaluation of CLA+ T cells in the blood may eliminate the need for skin biopsies. Preliminary work in AD has established that disease‐associated T‐cell abnormalities can be approached by either a study of skin lesions or activated CLA+ T‐cell subsets in peripheral blood. Future studies in adults and children, across different skin disorders, correlating blood and skin phenotypes and determining skin‐homing T‐cell functional properties are needed to establish whether CLA+ memory subsets can be used as biomarkers and a substitute for skin biopsies. This review summarizes the latest advancements reached on circulating CLA+ in AD and the great potential they harbor in understanding AD mechanisms.

The spectrum of manifestations in desmoplakin gene (DSP) spectrin repeat 6 domain mutations: Immunophenotyping and response to ustekinumab

Background The immune abnormalities underlying the ichthyoses are poorly understood. Objective To determine the immunophenotype of an ichthyosis resulting from mutations in the spectrin repeat 6 (SR6) domain of desmoplakin gene (DSP) and target therapy on the basis of molecular pathogenesis. Methods Immunophenotyping was performed by using the blood and skin of a girl with SR6 region DSP mutations causing erythroderma/ichthyosis and cardiomyopathy. Results On the basis of the discovery of T helper 1 and T helper 17/interleukin 23 skewing in the skin and T helper 17/interleukin 22 skewing in blood, ustekinumab therapy was initiated. Ustekinumab was also administered to a boy with an SR6 region DSP mutation and ichthyosis without cardiomyopathy. Both children responded despite previous poor responses to immunosuppressants and retinoids. Limitations Small number of patients and immunophenotyping in only 1 patient. Conclusion An understanding of the molecular basis of inflammation in rare cutaneous disorders can lead to targeted therapy, which promises to be more beneficial than broad immunosuppressants.