Spatial and Temporal Variation in the Skin Transcriptome of Atopic Dermatitis Assessed by 1.5 mm Mini Punch Biopsies

To obtain a detailed molecular understanding of both the temporal and spatial variation in atopic dermatitis (AD), we conducted a longitudinal case-control study, in which we followed a population, the Gentofte AD (GENAD) cohort, of mild-to-moderate AD patients and matched healthy controls for more than a year. By the use of 1.5 mm punch biopsies, we obtained 393 samples from lesional, non-lesional and healthy skin, from multiple anatomic regions at different time points for transcriptomic profiling. After quality control, 339 samples remained for further analysis. We envisage that the application of small biopsies, such as those introduced in this study, combined with omics technologies, will enable future skin research, in which multiple sampling from the same individual will give a more detailed, dynamic picture of how a disease fluctuates in time and space. Overall design: 30 AD patients and 30 healthy, age- and gender-matched healthy controls (HC) were enrolled in the study. For AD patients, biopsy specimens (1.5 mm) were taken at two lesional (LS) and two non-lesional (NL) skin sites. For HC, two skin biopsies were taken, preferably from the upper inner arm. A subpopulation of patients with AD and HC continued in a longitudinal study, where skin biopsies were taken at 3, 6, 9 and 12 months after the baseline visit. In total, and after quality control, 339 samples were included for transcriptomic profiling.