Predictors of AD in infants: Non-invasive immune biomarkers

29 Sep 2022

Atopic dermatitis (AD) is a chronic and recurrent inflammatory skin disease that develops in genetically susceptible individuals, as a result of epithelial barrier breakdown and immunological dysregulation.1 Discovery of predictive biomarkers is crucial for preventing and reducing the incidence of AD in children.2

A Danish prospective study examined if immune and skin barrier biomarkers can predict the onset and severity of AD during the first 2 years of life, and found increased levels of serum thymus activation-regulated chemokine (TARC) and interleukine-8 (IL-8) to be significantly associated with developing AD.2 This study, entitled the Barrier dysfunction in Atopic newBorn (BABY) study, examined a cohort of 300 term and 150 preterm newborns.2 Skin examination was done at birth, at 2 months, and at any point where there was any sign of AD, then followed up for 2 years.2 Tape strips were used to examine the skin at birth and at 2 months, and any sign of AD was scored using the Eczema Area and Severity Index (EASI).2 The protein levels of immune biomarkers were evaluated from the sample on the tape strip.2 Filaggrin (FLG), a gene that encodes a skin barrier protein and gene mutation, was evaluated at birth.2 Children with AD at the time of collecting tape strips were excluded.2

As said, the study included a total of 300 term (43% male) and 126 preterm (37% male) newborns.3 The prevalence of AD was 34.6% in term and 21.2% in preterm children.2 The EASI score was 4.2 [Interquartile range (IQR)=2.0-7.9] and 1.6 (IQR=1.1-3.1) among term and preterm children, respectively.2

The elevated TARC levels significantly increased the risk of developing AD (p=0.007) and were strongly associated with moderate-to-severe AD (p=0.0007) in term children, at 2 months.3 The cumulative risk of AD onset and moderate-to-severe AD were significantly higher in children who had elevated levels of TARC.2 The TARC levels were found to be significantly elevated both in children <6 months and children between the age of 6-24 months who developed AD (p=0.0004 and p=0.003), respectively.3 TARC was also found to be significantly increased (p=0.05) in preterm children who developed AD vs. preterm children who did not.2

Moreover, the IL-8 levels were also found to be significantly higher in term children who developed AD (p=0.02) compared with those who did not.3 At birth, no biomarker was associated with AD.2

The authors concluded that to their knowledge, this was the first study to show that biomarkers collected non-invasively can be reliable in predicting AD onset.2 Of note, the authors emphasized that the samples collected as early as 2 months were associated with AD that developed several months later, indicating that these biomarkers constituted an important early step in disease development, and hence could be useful for the design of targeted clinical trials in the pediatric population.2

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