To determine differences in the differentiation of Tregs/Tresps we calculated the percentages of CD45RA+CD31+ recent thymic emigrant (RTE) Tregs/Tresps and CD45RA+CD31− mature naive (MN) Tregs/Tresps, as well as CD45RA−CD31+ and CD45RA−CD31− memory Tregs/Tresps (CD31+ and CD31− memory Tregs/Tresps) within the total Treg/Tresp pool of 78 SLE remission patients compared with 94 healthy controls of different ages. This evidence concerns the gene PECAM1 and systemic lupus erythematosus.