To test the possible involvement of N CD4 T cells in early disease stages, their frequency was tested in relatives of patients with type 1 diabetes who transitioned from Stage 0 (at T0) to Stage≥1 (at T1) and in a cohort of age and sex-matched relatives who maintained the Stage 0 status both at T0 and T1. Here, CD4 is linked to type 1 diabetes mellitus.