In our study of 18 T1D and nine control subjects, deep sequencing of TCRs from T cell subsets (isolated from pLN, spleen, PBMC, and inguinal or mesenteric LN) showed that limited Treg or conventional CD4+ T cell (Tconv) repertoire overlap exists across tissues and in the circulation within a given individual (i.e., 3–4% overlap between pLN and PBMC for T1D donors) [38•]. Here, CD4 is linked to type 1 diabetes mellitus.