Assessment of Spatial and Temporal Variation in the Skin Transcriptome of Atopic Dermatitis by Use of 1.5 mm Minipunch Biopsies.

Atopic dermatitis (AD) is a common inflammatory skin disorder characterized by a heterogeneous and fluctuating disease course. To obtain a detailed molecular understanding of both the temporal and spatial variation in AD, we conducted a longitudinal case-control study, in which we followed a population, the GENAD (Gentofte AD) cohort, of mild-to-moderate patients with AD and matched healthy controls for more than a year. By the use of 1.5 mm minipunch biopsies, we obtained 393 samples from lesional, nonlesional, and healthy skin from multiple anatomical regions at different time points for transcriptomic profiling. We observed that the skin transcriptome was remarkably stable over time, with the largest variation being because of disease, individual, and skin site. Numerous AD-specific, differentially expressed genes were identified and indicated a disrupted skin barrier and activated immune response as the main features of AD. We also identified potentially novel targets in AD, including IL-37, MAML1, and several long noncoding RNAs. 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.