Virtually every living cell releases extracellular vesicles (EV), which can be classified based on size and marker expression. One of the smallest known groups of EV, exosomes, have a diameter typically ranging from 30 to 100 nm and originate from endosomes
[1]. Composed of lipids, proteins and nucleic acids, these ubiquitous vesicles are thought to be involved in multiple diseases, including inflammatory and autoimmune skin conditions
[2]. Due to their physical characteristics, which allow them to carry molecules across long distances, EV are often explored for their potential as biomarkers
[3,4][3][4]. Physiologically, small EV (sEV), such as exosomes, are key mediators of cellular communication, namely through microRNAs
[5]. Hence, depending on the producing cell, sEV may have modulating characteristics, which can potentially be harnessed for therapeutic purposes. In fact, these naturally-produced vesicles are currently explored for the treatment of several conditions, including wound healing
[6] and autoimmune diseases
[7,8,9][7][8][9]. Their use replaces cell therapies
[10[10][11],
11], while conferring advantages, namely concerning handling and formulation.
Umbilical cord blood (UCB) is a rich source of stem cells and immature T-cells
[16][12] with potent suppressive ability
[17][13]. The collection of UCB, commonly seen as medical waste, is non-invasive and has limited ethical concerns. It has previously been shown that sEV from UCB mononuclear cells (UCB-MNC-sEV), produced using an established optimized protocol
[18][14], accelerate the healing of diabetic wounds
[6] and have a good safety profile
[19][15].