Table 1.

Tissue-resident memory T (TRM) cell markers used by authors to define skin TRM cells. Often, a combination of markers was used. For the most part, TRM cells were either defined as CD3⁺, CD4⁺ or CD8⁺ T cells with an expression or absence of different markers. CD49a (α-subunit of the α1β1 integrin receptor) is another marker with important delineating functional implications. CD69 suppresses sphingosine-1-phosphate receptor 1 expression, which prevents T cell egress from tissues into the circulation. CD103 binds E-cadherin on epithelial cells, which mediates retention of T cells in the skin.

TRM Marker	Study
CD3	[18,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52]
CD4	[18,26,27,31,33,34,35,36,37,39,40,41,42,44,45,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77]
CD8	[14,18,27,28,29,30,31,32,33,34,35,36,37,38,40,41,42,43,44,45,46,47,48,49,51,52,53,54,55,56,57,58,59,60,62,63,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110]
CD27	[34,62]
CD39	[32]
CD44	[34,35,43,50,64,65,76,92]
CD45RA	[34,52]
CD45RO	[26,37,40,52,62,66,73,74,111]
CD49a	[27,51,80,84,101]
CD62L	[34,35,50,52,64,65,71,72,76,83,84,92]
CD69	[14,18,27,28,29,30,31,32,33,34,35,36,38,39,40,41,42,44,45,47,48,49,50,51,52,53,54,55,57,59,60,61,63,64,66,67,68,69,70,71,72,73,74,75,76,77,80,81,82,83,85,87,88,89,90,92,93,95,98,99,100,105,106,108,112,113,114,115]
CD103	[14,18,27,28,29,30,32,33,34,35,36,38,39,40,41,42,43,44,45,47,48,51,52,53,54,57,58,59,60,63,64,65,66,67,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,92,93,94,95,96,98,99,100,101,102,103,104,105,106,108,109,112,113,115,116]
CD122	[71,72,76]
CD127	[76]
CCR4	[34,62]
CCR6	[52,54]
CCR7	[34,52,55,61,73]
CCR8	[44]
CLA	[36,54,59,62]
CXCR6	[64]
KLRG1	[84]
TCRα/β	[34]
TCRγ/δ	[34]
VLA-1	[100]
Vγ3	[41]
Vγ4	[117]
Vδ4	[117]
γδ	[117]