PDCD1 and type 1 diabetes mellitus: It is interesting to note that in our study, upon Pep3 pre-treatment after 4 or 6 days of stimulation, percentages of total CD8+ Teff PD1+, CD8+ Teff PD1low PBMC were significantly increased in type 1 diabetes patients compared to normal controls, while percentages of CD8+ Teff PD1high were increased in both diabetics and normal controls.