Interestingly, there were no significant differences in the naïve (CD45RA+) and memory (CD45RA-) natural regulatory T cells (Tregs) (CD3+CD4+CD25+FoxP3+CTLA4+TIGIT+PD1+/-) between SLE and healthy except for an increase in memory Tregs in the paediatric population (SLE versus healthy: 1.16 [0.79 to 1.92]%; 0.48 [0.32 to 0.80]%, p<0.0001). Here, PDCD1 is linked to systemic lupus erythematosus.