TARC, IL-8, and IL-18 predictive of AD
Multiple immune biomarkers were tested, including various cytokines and filaggrin degradation products. On examination of skin samples collected at birth, no particular biomarkers were found at higher levels among children who developed AD in comparison with those who did not develop AD.
With regard to biomarkers examined in skin samples at 2 months of age, however, the results were different, Dr. Halling said. One particular cytokine, thymus and activation-regulated chemokine (TARC), was seen to double the risk of AD in the first 2 years of a child’s life.
This doubled risk was seen not only among the children born at term but also among those born preterm, although the data were only significant with regard to the children born at term.
The unadjusted hazard ratios and adjusted HRs (adjusted for parental atopy and filaggrin gene mutations) in term children were 2.11 (95% confidence interval, 1.36-3.26; P = .0008) and 1.85 (95% CI, 1.18-2.89; P = .007), respectively.
For preterm children, the HRs were 2.23 (95% CI, 0.85-5.86; P = .1) and 2.60 (95% CI, 0.98-6.85; P =.05), respectively.
These findings were in line with findings of other studies, Dr. Halling said. “It is well recognized that TARC is currently the best biomarker in patients with established atopic dermatitis.” Moreover, she reported that TARC was associated with a cumulative increase in the risk for AD and that levels were found to be higher in children in whom onset occurred at a later age than among those diagnosed before 6 months of age.
“This is important, as these findings shows that TARC levels predict atopic dermatitis that occurred many months later,” Dr. Halling said.
And, in term-born children at least, TARC upped the chances that the severity of AD would be greater than had it not been present (adjusted HR, 4.65; 95% CI, 1.91-11.31; P = .0007).
Increased levels of interleukin-8 (IL-8) and IL-18 at 2 months of age were also found to be predictive of having moderate to severe AD. The risk was more than double in comparison with those in whom levels were not increased, again only in term-born children.
‘Stimulating and interesting findings’
These data are “very stimulating and interesting,” Dedee Murrell, MD, professor and head of the department of dermatology at St. George Hospital, University of New South Wales, Sydney, observed at the press briefing.
“You found this significant association mainly in the newborn children born at term, and the association in the preterm babies wasn’t as high. Is that anything to do with how they were taken care of in the hospital?” Dr. Murrell asked.
“That’s a really good question,” Dr. Halling said. “Maybe they need to be exposed for a month or two before we are actually able to identify which children will develop atopic dermatitis.”
The study was funded by the Lundbeck Foundation. Dr. Halling has acted as a consultant for Coloplast and as a speaker for Leo Pharma. Dr. Murrell has disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.