The larger subpopulation of cells (subcluster 0) included a subgrouping of cells, highly expressing CCL19 showing a strong trend toward more SSc fibroblasts (Fig. 3b), the SSc CCL19+ fibroblasts clustering separately from the control CCL19+ fibroblasts (Fig. 2c), expressing higher levels of CCL19 (Fig. 3a) and localizing primarily perivascularly (Supplementary Fig. 4). Here, CCL19 is linked to systemic sclerosis.