Cutaneous T cell lymphoma (CTCL) is a potentially fatal clonal malignancy of T cells, presenting as skin eruptions. Lack of CTCL-specific tumour markers and similarity to non-malignant inflammatory skin diseases present major clinical challenges resulting in delayed diagnosis.
Integrating gene expression of generated and mined datasets from CTCL, atopic dermatitis, psoriasis and healthy skin of 237 patients, we detected disease-specific immune subsets and patient-specific signatures of malignant cells with high inter-tumour heterogeneity. However, when employing similarity mapping for CTCL donors, we identified signatures shared by all tumours, including increased glycolytic activity and stress response genes. Central memory-like malignant T cell clones were present in early CTCL stages, while effector-like clones shaped a Th2-permissive tumour microenvironment in late CTCL. Surprisingly, the CTCL microenvironment was characterized by specialized fibroblast subsets with the signature of lymphoid organ fibroblasts. Accordingly, we detected intra-tumoral B cell aggregates and tertiary lymphoid structure formation, which were not present in inflammatory skin disease. Increased B cell accumulation was associated with progressive CTCL and may present a novel histological hallmark for diagnosis and staging.

LB010 - A specialized B cell-rich tumor microenvironment delineates cutaneous T cell lymphoma from benign inflammatory skin diseases

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.