Interleukin-8 Levels in the Stratum Corneum as a Biomarker for Monitoring Therapeutic Effect in Atopic Dermatitis Patients.

INTRODUCTION

The stratum corneum contains several growth factors and cytokines that are synthesized in keratinocytes. We previously reported that the amount of interleukin-8 in the stratum corneum (scIL-8) is related to the severity of local skin inflammation in atopic dermatitis (AD). However, it is unknown whether scIL-8 levels reflect pharmacologic responses to a therapeutic intervention in AD patients. Therefore, in this study, we aimed to investigate whether the improvement of dermatitis in AD is correlated with scIL-8 levels before and after topical corticosteroid treatment.

METHODS

Stratum corneum samples were collected from 22 AD patients using the noninvasive tape-stripping method before treatment, 2 weeks after topical treatment, and 4-6 weeks after treatment.

RESULTS

scIL-8 levels on the forearm reduced significantly from 790 ± 348 pg/mg before treatment to 163 ± 68 pg/mg 2 weeks after treatment and 100 ± 37 pg/mg 4-6 weeks after corticosteroid treatment. scIL-8 levels on the abdomen also reduced significantly from 902 ± 391 to 142 ± 38 pg/mg at the end of study. The reduction in scIL-8 levels was associated with the improvement in local skin severity in AD. We also found that scIL-8 levels, along with blood biomarker levels (serum thymus and activation-regulated chemokine, lactate dehydrogenase, and %eosinophil), decreased significantly after the treatment.

CONCLUSION

The scIL-8 concentration decreases with improvements in skin symptoms in AD patients after topical corticosteroid treatment; thus, it may be a suitable biomarker for monitoring therapeutic effects in AD patients.