Eczema and sensitization to common allergens in the United States: a multiethnic, population-based study

Association between dietary antioxidants intake and childhood eczema: results from the NHANES database

BACKGROUND

High dietary intake of antioxidants reduces the risk of allergic sensitization in children. However, there was no sufficient evidence for the effect of dietary antioxidants intake on childhood eczema. Herein, this study aimed to explore the roles of different dietary antioxidants in childhood eczema.

METHODS

Data of 2305 children and adolescents aged < 18 years old were extracted from the National Health and Nutrition Examination Survey database in 2005-2006 in this cross-sectional study. The associations between dietary antioxidants intake and childhood eczema were explored using univariate and multivariate logistic regression analyses, with odds ratios (ORs) and confidence intervals (CIs). Subgroup analyses based on age and gender were also performed.

RESULTS

A total of 268 (11.6%) children had eczema. After adjusting for covariates, we found no significant associations between dietary intake of β-carotene, vitamin C, selenium (Se), and retinol and childhood eczema. However, compared with children and adolescents whose dietary zinc (Zn) intake < 7.47 mg, those who had dietary Zn intake level ≥ 11.83 mg seemed to have lower odds of eczema [OR 0.45, 95% CI 0.28-0.73]. In addition, subgroup analysis showed that especially in children and adolescents aged 1-11 years old, whatever the gender, a higher dietary intake level of Zn may benefit childhood eczema (all P < 0.05).

CONCLUSION

We concluded dietary Zn intake was negatively associated with childhood eczema. Further studies are needed to explore the roles of dietary antioxidants intake in childhood eczema.

A 1% colloidal oatmeal OTC cream is clinically effective for the management of mild to moderate atopic dermatitis in Black or African American children

BACKGROUND

The efficacy and safety of an over-the-counter (OTC) 1% colloidal oatmeal cream versus a ceramide-based prescription barrier cream in children with mild-to-moderate atopic dermatitis (AD) were previously described.

OBJECTIVES

Here, findings are reported for the Black/African American subgroup.

METHODS

Patients were randomized to 1% oatmeal cream or prescription barrier cream twice daily or as needed for three weeks. Assessments included Eczema Area and Severity Index (EASI) scores, Investigator's Global Atopic Dermatitis Assessment (IGADA) scores, and patients'/caregivers' assessment of eczema signs and symptoms.

RESULTS

Overall, 49 Black/African American children aged 2-15 years with mild/moderate AD were included. At week 3, mean (SD) changes from baseline in EASI scores were -2.4 (1.7) with 1% oatmeal cream and -2.1 (2.3) with barrier cream; improvements were observed from week 1. At week 3, mean (SD) changes from baseline in IGADA scores were -0.6 (0.7) and -0.7 (0.6), respectively. Improvements in subjective ratings of signs/symptoms of eczema were observed. Both study treatments were well tolerated.

CONCLUSION

OTC 1% oatmeal cream was at least as effective and safe as prescription barrier cream in this population, providing a novel, fast-acting, and cost-effective option for the symptomatic treatment of mild-to-moderate AD in Black/African American children.

A cross-sectional study of pediatric dermatoses in a specialized pigment and skin-of-color center in Australia

There is a paucity of literature on pediatric skin conditions in skin of color, of which old epidemiological data are likely to become outdated as the ethnic diversity in developed countries such as Australia continues to grow. We analyzed the prevalence of presenting conditions of pediatric patients with skin of color attending an urban dermatology clinic in Melbourne, Australia over an 18-month period. The major presenting issues were vitiligo, atopic dermatitis, and acne vulgaris, the majority of which did not significantly differ by ethnicity; however, there was a statistically significantly higher proportion of Chinese and Indian patients presenting with atopic dermatitis. Given the varying presentations of these conditions in skin of color, our findings highlight the importance of increasing education for dermatologists and health personnel in pigmentary disorders and the need for further focused studies comparing the prevalence of skin disease across ethnicities.

Glutamine and lysine as common residues from epitopes on α-lactalbumin and β-lactoglobulin from cow milk identified by phage display technology

Cow milk is an important source of food protein for children; however, it could lead to allergy, especially for infants. α-Lactalbumin (α-LA) and β-lactoglobulin (β-LG) from whey protein make up a relatively high proportion of milk proteins and have received widespread attention as major allergens in milk. However, few studies have identified the epitopes of both proteins simultaneously. In this study, ImmunoCAP and indirect ELISA were first used for detection of sIgE to screen sera from allergic patients with high binding capacity for α-LA and β-LG. Subsequently, the mimotopes was biopanned by phage display technology and bioinformatics and 17 mimic peptide sequences were obtained. Aligned with the sequences of α-LA or β-LG, we identified one linear epitope on α-LA at AA 11-26 and 5 linear epitopes on β-LG at AA 9-29, AA 45-57, AA 77-80, AA 98-101, and AA 121-135, respectively. Meanwhile, the 8 conformational epitopes and their distributions of α-LA and β-LG were located using the Pepitope Server. Finally, glutamine and lysine were determined as common AA residues for the conformational epitopes both on α-LA and β-LG. Moreover, we found the addition of mouse anti-human IgE during the biopanning process did not significantly affect the identification of the epitopes.

The Impact of Air Pollution on Atopic Dermatitis

PURPOSE OF REVIEW

Atopic dermatitis (AD) remains a dermatological disease that imposes a significant burden on society. Air pollution has previously been linked to both the onset and severity of atopic dermatitis. As air pollution remains a critical environmental factor impacting human health, this review seeks to provide an overview of the relationship between different air pollutants and AD.

RECENT FINDINGS

AD can develop from multiple causes that can be broadly grouped into epidermal barrier dysfunction and immune dysregulation. Air pollution imposes significant health risks and includes a wide variety of pollutant types. AD has been linked to outdoor air pollutants such as particulate matter (PM), volatile organic compounds (VOC), gaseous compounds, and heavy metals. Exposure to indoor pollutants such as tobacco smoke and fungal molds has also been associated with an increased incidence of AD. While different pollutants impact distinct molecular pathways in the cell, they mostly converge on ROS product, DNA damage, and dysregulated T-cell activity and cytokine production. The presented review suggests a strengthening tie between air pollution and AD. It points to opportunities for further studies to clarify, as well as potential therapeutic opportunities that leverage the mechanistic relationships between air pollution and AD.

Variations in genetics, biology, and phenotype of cutaneous disorders in skin of color. Part II: Differences in clinical presentation and disparities in cutaneous disorders in skin of color

Skin of color (SOC) patients are projected to comprise the majority of the population by 2044, yet knowledge gaps in the clinical presentation and treatment of both common and uncommon dermatologic conditions in skin of color persist. Improved awareness of disparities that disproportionately impact SOC patients is necessary to address health inequity in the field of dermatology. The first part of this CME discussed structural, genetic, and immunophenotypic differences in SOC in common inflammatory disorders as well as cutaneous malignancies. The second part of this CME highlights clinical differences in the phenotypic presentation of the inflammatory disorders of atopic dermatitis, psoriasis, and hidradenitis suppurativa as well as the cutaneous malignancies of melanoma, basal cell carcinoma, and cutaneous T-cell lymphoma. Health disparities associated with each of these conditions are also discussed.

Variations in genetics, biology, and phenotype of cutaneous disorders in skin of color - Part I: Genetic, biologic, and structural differences in skin of color

Skin of color (SOC) populations include those who identify as Black/African, Hispanic/Latinx, Asian/Pacific Islander, American Indian/Native Alaskan, Indigenous Australian, Middle Eastern, biracial/multiracial, or non-White; this list is far from exhaustive and may vary between and within cultures. Recent genetic and immunological studies have suggested that cutaneous inflammatory disorders (atopic dermatitis, psoriasis, and hidradenitis suppurativa) and malignancies (melanoma, basal cell carcinoma, and cutaneous T-cell lymphoma) may have variations in their immunophenotype among SOC. Additionally, there is growing recognition of the substantial role social determinants of health play in driving health inequalities in SOC communities. It is critically important to understand that social determinants of health often play a larger role than biologic or genetic factors attributed to "race" in health care outcomes. Herein, we describe the structural, genetic, and immunological variations and the potential implications of these variations in populations with SOC. This article underscores the importance of increasing the number of large, robust genetic studies of cutaneous disorders in SOC to create more targeted, effective therapies for this often underserved and understudied population. Part II of this CME will highlight the clinical differences in the phenotypic presentation of and the health disparities associated with the aforementioned cutaneous disorders in SOC.

The association between domestic hard water and eczema in adults from the UK Biobank cohort study

BACKGROUND

Eczema is a chronic inflammatory skin disease. Domestic water with high mineral content (hard water) is a risk factor for eczema in children, but this association has not been assessed in adults.

OBJECTIVES

To examine the association between domestic hard water supply and eczema prevalence and incidence in adults aged 40-69 years and the contextual effect in eczema outcomes by postcode in adults in the UK.

METHODS

We used data from the UK Biobank study collected in 2006-10 (baseline) and 2013-14 (follow-up). Eczema prevalence at baseline (2006-10) and at follow-up (2013-14) and incidence (new onset between baseline and follow-up) were determined from the touchscreen questionnaires and nurse-led interviews. Domestic hard water information was obtained in 2005 and 2013 from the local water supply companies in England, Wales and Scotland as CaCO3 concentrations. We fitted multilevel logistic regression models with random intercepts for postcode areas to examine the effect of domestic hard water on eczema outcomes, and we measured components of variance.

RESULTS

In total, 306 531 participants with a mean age of 57 years nested across 7642 postcodes were included in the baseline analysis, and 31 036 participants nested across 3695 postcodes were included in the follow-up analysis. We observed an increase in the odds of eczema at baseline [odds ratio (OR) 1·02, 95% confidence interval (CI) 1·01-1·04] per 50 mg L-1 of CaCO3 increase. Furthermore, exposure to domestic hard water (> 200 mg L-1 of CaCO3 ) was associated with increased odds of prevalent eczema at baseline (OR 1·12, 95% CI 1·04-1·22). Moreover, there was a significant linear trend (P < 0·001) in which increasing levels of hard water increased eczema prevalence risk. No association was observed with incident eczema or eczema at follow-up. The intraclass correlation coefficient for postcode was 1·6% (95% CI 0·7-3·4), which remained unexplained by area-level socioeconomic measures.

CONCLUSIONS

Increasing levels of domestic hard water, as measured by CaCO3 concentrations, were associated with an increased prevalence of eczema in adults but not increased incidence. Ongoing efforts to reduce hard water exposure may have a beneficial effect in reducing the burden of eczema in adults. Further research is needed to explore area-level factors that may lead to eczema. What is already known about this topic? Hard water is formed when minerals are dissolved in water from filtration through sedimentary rocks. Several studies have reported a higher prevalence of eczema in areas with hard water. However, all studies on this topic have assessed this in infants and school-aged children, while this association has not been explored in adults. What does this study add? Our findings suggest that exposure to higher concentrations of domestic hard water is associated with an increase in eczema prevalence in adults aged 40-69 years. Ongoing efforts to reduce hard water exposure may have a beneficial effect in reducing eczema prevalence in adults.

Financial burden and impact of atopic dermatitis out-of-pocket healthcare expenses among black individuals in the United States

Black race is associated with increased atopic dermatitis (AD) severity and healthcare resource utilization. However, the burden of out-of-pocket (OOP) expenses among black individuals with AD is not well understood. We sought to characterize the categories and impact of OOP healthcare expenses associated with AD management among black individuals. A 25-question voluntary online survey was administered to National Eczema Association members (N = 113,502). Inclusion criteria (US residents age ≥ 18 years; self-report of AD or primary caregivers of individuals with AD) was met by 77.3% (1118/1447) of respondents. Black individuals with AD were younger, had lower household income, Medicaid, urban residence, poor AD control and frequent skin infections (P ≤ 0.02). Blacks vs. non-blacks reported more OOP costs for prescription medications covered (74.2% vs. 63.6%, P = 0.04) and not covered (65.1% vs. 46.5%, P = 0.0004) by insurance, emergency room visits (22.1% vs. 11.8%, P = 0.005), and outpatient laboratory testing (33.3% vs. 21.8%, P = 0.01). Black race was associated with increased household financial impact from OOP expenses (P = 0.0009), and predictors of financial impact included minimally controlled AD (adjusted OR [95% CI] 13.88 [1.63-117.96], P = 0.02), systemic therapy (4.34 [1.63-11.54], 0.003), > $200 monthly OOP expenses (14.28 [3.42-59.60], P = 0.0003), and Medicaid (4.02 [1.15-14.07], P = 0.03). Blacks with Medicaid had higher odds of harmful financial impact (3.32 [1.77-6.24], P = 0.0002) than those of black race (1.81 [1.04-3.15], P = 0.04) or with Medicaid (1.39 [1.02-1.88], P = 0.04) alone. Black race is associated with increased OOP costs for AD and significant household financial impact. Targeted interventions are needed to address financial disparities in AD.

Association between atopic dermatitis and race from infancy to early childhood: a retrospective cohort study

BACKGROUND

Atopic dermatitis (AD) is a common pediatric skin condition with significant morbidity. It is unclear what factors contribute to racial differences in disease prevalence.

METHODS

A single-site, retrospective cohort study of infants born from June 1, 2011, to April 30, 2017, was performed.

RESULTS

Of the 4016 infants included, 39.2% (n = 1574) were Black, 38.5% (n = 1543) White (non-Hispanic), 7.1% (n = 286) Hispanic, 5.3% (n = 213) Asian, 6.5% (n = 262) "other" race, 3.4% (n = 135) multiracial, and 0.1% (n = 3) not reported. Prevalence of AD differed by race, with 37.0% (n = 583) of Black, 25.8% (n = 55) of Asian, 24.1% (n = 69) of Hispanic, 23.0% (n = 31) of multiracial, 19.1% (n = 50) of "other" race, and 17.9% (n = 276) of White patients diagnosed (P < 0.0001). Delivery mode, NICU stay, and gestational age were all significantly associated with race. In modeling AD with logistic regression, race was significantly associated with the development of AD (P < 0.0001, OR Black = 2.6 [2.2-3.2], OR Asian = 1.6 [1.1-2.2], OR Hispanic = 1.4 [1.0-1.9], OR multiracial 1.4 [0.91-2.2], OR "other" 0.97 [0.67-1.4], and OR White 1.0).

CONCLUSIONS

Racial differences in rates of AD arise early in life. Diagnosis is associated with race rather than delivery mode, insurance type, and gestational age. Further investigation into these disparities and interventions to mitigate them should focus on infancy and early childhood.

Association between ambient air pollution and development and persistence of atopic and non-atopic eczema in a cohort of adults

BACKGROUND

There is limited information on risk factors for eczema in adults. Recent evidence suggests that air pollution may be associated with increased incidence of eczema in adults. We aimed to assess this possible association.

METHODS

Ambient air pollution exposures (distance from a major road, nitrogen dioxide [NO₂ ], fine particulate matter with an aerodynamic diameter ≤2.5 µm [PM_2.5 ]) were assessed for the residential address of Tasmanian Longitudinal Health Study participants at ages 43 and 53 years. Eczema incidence (onset after age 43 years), prevalence (at 53 years), and persistence were assessed from surveys, while IgE sensitization was assessed using skin prick tests. The presence or absence of eczema and sensitization was classified into four groups: no atopy or eczema, atopy alone, non-atopic eczema, and atopic eczema. Adjusted logistic and multinomial regression models were fitted to estimate associations between ambient air pollution and eczema, and interaction by sex was assessed.

RESULTS

Of 3153 participants in both follow-ups, 2369 had valid skin prick tests. For males, a 2.3 ppb increase in baselineNO₂ was associated with increased odds of prevalent eczema (OR = 1.15 [95% CI 0.98-1.36]) and prevalent atopic eczema (OR = 1.26 [1.00-1.59]). These associations were not seen in females (p for interaction = 0.08, <0.01). For both sexes, a 1.6 µg/m³ increase in PM_2.5 exposure at follow-up was associated with increased odds of aeroallergen sensitization (OR = 1.15 [1.03-1.30]).

CONCLUSION

Increased exposure to residential ambient air pollutants was associated with an increased odds of eczema, only in males, and aeroallergen sensitization in both genders.

Lower Use of Biologics for the Treatment of Asthma in Publicly Insured Individuals

BACKGROUND

Despite bearing a disproportionate burden of poorly controlled asthma, publicly insured individuals are less likely to receive biologics.

OBJECTIVE

To assess biologic use by payer among individuals with asthma.

METHODS

We used IQVIA's National Disease and Therapeutic Index, a nationally representative, all-payer audit of ambulatory care in the United States, to describe the patterns of use by payer.

RESULTS

Asthma treatment visits in which a biologic product was reported increased from approximately 0.1% of asthma-related visits in 2003 to 1% in 2015 and doubled to 2% by 2019. Omalizumab use initially increased from 2003 to 2006 and plateaued till 2015 when its use declined modestly, coinciding with the release of additional biologic products. In 2019, omalizumab accounted for 37% of biologic treatment visits, mepolizumab 21%, benralizumab 27%, dupilumab 15%, and reslizumab <1%. Biologic treatment visits were higher for privately insured individuals (28.3 per 1000 visits) compared with publicly insured individuals (16.3 per 1000 visits). This difference persisted after accounting for age, sex, and race using nationally representative estimates. Whites accounted for a disproportionate amount of biologic treatment visits among the publicly insured (80%) despite accounting for only 60% of publicly insured asthma treatment visits. No biologic treatment visits were observed for individuals who were uninsured. Half of dupilumab visits were for publicly insured patients, compared with 22% of mepolizumab/benralizumab and 27% of omalizumab visits.

CONCLUSION

Biologics were uncommonly used among patients with asthma, and the basis for disproportionately lower use of biologics among the publicly insured, where the burden of uncontrolled asthma is greatest, merits further investigation.

Global differences in atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disorder, with a highly variable prevalence worldwide. Recent evidence, however, has shown an increase in prevalence in the Asia Pacific region. Nevertheless, most of the published literature has focused mainly on Western populations, and only few clinical trials have included subgroups of other ethnic populations. Reasons for the observed ethnic and geographical differences in AD are not well established. This calls into question the need for a better understanding of AD pathogenesis and inter-ethnic differences in clinical and immuno-phenotypes. These differences may reflect inherent variability in disease mechanisms between populations, which in turn may impact upon treatment responses such as biologics that are currently tailored mainly to a specific immuno-phenotype (T-helper type 2 dominant). In this article, we reviewed existing literature on the prevalence of AD globally, highlighting differences, if any, in the clinical and immuno-phenotypes of AD between different ethnicities. We discussed genetic and environmental factors that affect AD in different populations and therapeutic considerations. Our review highlights AD as a disease with ethnic-dependent clinical and immunological heterogeneity and calls for greater inclusion of ethnic diversity in future research in order to develop targeted treatments.

The exposome in atopic dermatitis

Atopic dermatitis (AD) is a complex inflammatory disorder with multiple interactions between genetic, immune and external factors. The sum of external factors that an individual is exposed to throughout their lifetime is termed the exposome. The exposome spans multiple domains from population to molecular levels and, in combination with genetic factors, holds the key to understanding the phenotypic diversity seen in AD patients. Exposomal domains are categorized into nonspecific (human and natural factors affecting populations), specific (eg humidity, ultraviolet radiation, diet, pollution, allergens, water hardness) and internal (cutaneous and gut microbiota and host cell interaction) exposures. The skin, as the organ that most directly interacts with and adapts to the external environment, is a prime target for exploration of exposomal influences on disease. Given the well-recognized physical environmental influences on AD, this condition could be much better understood through insightful exposomal research. In this narrative review, we examine each domain in turn, highlighting current understanding of the mechanisms by which exposomal influences modulate AD pathogenesis at distinct points in time. We highlight current approaches to exposome modification in AD and other allergic disease and propose future directions for exposome characterization and modification using novel research techniques.

Atopic dermatitis in African American patients is TH2/TH22-skewed with TH1/TH17 attenuation

BACKGROUND

African Americans (AA) are disproportionately impacted by atopic dermatitis (AD), with increased prevalence and therapeutic challenges unique to this population. Molecular profiling data informing development of targeted therapeutics for AD are derived primarily from European American (EA) patients. These studies are absent in AA, hindering development of effective treatments for this population.

OBJECTIVE

We sought to characterize the global molecular profile of AD in the skin of AA patients as compared with that of EA AD and healthy controls.

METHODS

We performed RNA-Seq with reverse transcription polymerase chain reaction validation and immunohistochemistry studies in lesional and nonlesional skin of AA and EA AD patients vs healthy controls.

RESULTS

African American AD lesions were characterized by greater infiltration of dendritic cells (DCs) marked by the high-affinity immunoglobulin E (IgE) receptor (FcεR1+) compared with EA AD (P < .05). Both AD cohorts showed similarly robust up-regulation of Th2-related (CCL17/18/26) and Th22-related markers (interleukin [IL]-22, S100A8/9/12), but AA AD featured decreased expression of innate immune (tumor necrosis factor [TNF], IL-1β), Th1-related (interferon gamma [IFN-γ], MX1, IL-12RB1), and Th17-related markers (IL-23p19, IL-36G, CXCL1) vs EA AD (P < .05). The Th2 (IL-13) and Th22-related products (IL-22, S100A8/9/12) and serum IgE were significantly correlated with clinical severity (Scoring of Atopic Dermatitis [SCORAD]) in AA. Fillagrin (FLG) was exclusively down-regulated in EA AD, whereas loricrin (LOR) was down-regulated in both AD cohorts and negatively correlated with SCORAD in AA.

CONCLUSION

The molecular phenotype of AA AD skin is characterized by attenuated Th1 and Th17 but similar Th2/Th22-skewing to EA AD. Our data encourages a personalized medicine approach accounting for phenotype-specific characteristics in future development of targeted therapeutics and clinical trial design for AD.

Association of Infant Eczema with Childhood and Adult Asthma: Analysis of Data from the 1958 Birth Cohort Study

The influence of early life exposures on later life disease has for some time provided clues to modifiable risk factors of disease. The “atopic march” is thought to play a role in the progression of allergic diseases and may offer an opportunity to lower asthma’s health and socioeconomic burden, although evidence remains controversial. We aimed to examine the relationship between early life eczema and asthma later in life. Using the National Child Development Study, we examined infant eczema and childhood and adult asthma. Data related to asthma or wheezing bronchitis were available for 13,503 (73%; 95% CI 72–74), 11,503 (61%; 95% CI 60–61), 12,524 (68%; 95% CI 67–69), 11,194 (60%; 95% CI 60–60), 9377 (51%; 95% CI 51–51), and 9760 (53%; 95% CI 52–53) subjects at ages 11, 16, 23, 33, 44, and 50 years, respectively. Logistic regression models were fitted to examine each wave separately before and after adjusting for a range of potential confounders. Generalised estimating equation (GEE) methods were undertaken to examine the associations after pooling all data from questionnaires. The prevalence of self-reported asthma in those that had previously reported infant eczema ranged from 1.0%; 95% CI 0.9–1.4 (age 44 years) to 2.2%; 95% CI 2.1–2.3 (age 33 years). Participants with infant eczema had a 2–3-fold increased risk of reporting asthma in childhood and adulthood; this was 1.6 times at age 44 years when using spirometry measures. Similar effect sizes were observed in the GEE models when considering all participants (OR 2.9; 95% CI 2.6–3.2). Childhood and adult asthma were consistently associated with infant eczema both by using the self-reported data and lung measures.

Use of a Robotic Sampler (PIPER) for Evaluation of Particulate Matter Exposure and Eczema in Preschoolers

While the association of eczema with asthma is well recognized, little research has focused on the potential role of inhalable exposures and eczema. While indoor air quality is important in the development of respiratory disease as children in the U.S. spend the majority of their time indoors, relatively little research has focused on correlated non-respiratory conditions. This study examined the relationship between particulate matter (PM) exposures in preschool age children and major correlates of asthma, such as wheeze and eczema. Air sampling was carried out using a robotic (PIPER) child-sampling surrogate. This study enrolled 128 participants, 57 male and 71 female children. Ages ranged from 3 to 58 months with the mean age of 29.3 months. A comparison of subjects with and without eczema showed a difference in the natural log (ln) of PM collected from the PIPER air sampling (p = 0.049). PIPER's sampling observed an association between the ln PM concentrations and eczema, but not an association with wheezing history in pre-school children. Our findings are consistent with the hypothesis of the role of the microenvironment in mediating atopic dermatitis, which is one of the predictors of persistent asthma. Our findings also support the use of PIPER in its ability to model and sample the microenvironment of young children.

Characterization of human memory CD4(+) T-cell responses to the dog allergen Can f 4

BACKGROUND

The recently identified dog lipocalin allergen Can f 4 is an important respiratory allergen.

OBJECTIVE

We sought to comprehensively characterize the memory CD4(+) T-cell responses of allergic and nonallergic subjects to Can f 4.

METHODS

Can f 4-specific CD4(+)CD45RO(+) T-cell lines (TCLs) from allergic and healthy subjects were established and characterized by their functional and phenotypic properties. The epitope specificity of the TCLs was tested with 48 overlapping 16-mer peptides spanning the sequence of Can f 4. HLA restriction of the specific TCLs and the binding capacity of the epitope-containing peptides to common HLA class II molecules were studied.

RESULTS

Can f 4-specific memory CD4(+) TCLs were obtained at an 8-fold higher frequency from allergic than from nonallergic subjects. Functionally, the TCLs of allergic subjects exhibited a higher T-cell receptor avidity and expression of CD25 and predominantly produced IL-4 and IL-5. The TCLs of nonallergic subjects mostly secreted IFN-γ and IL-10, with high CXCR3 expression. Several distinct T-cell epitope regions along the allergen were identified. Importantly, the peptides from the region between amino acids 43 and 67 showed promiscuous HLA-binding capacity and induced memory CD4(+) T-cell responses in 90% of the allergic donors.

CONCLUSION

Productive TH2-deviated memory T-cell responses to Can f 4 are observed in allergic but not nonallergic subjects. A 19-mer peptide sequence covering the core of the immunodominant region of the allergen is a potential target for the development of peptide-based allergen immunotherapy.