In a study conducted in healthy patients and diabetes mellitus type 1 patients, a robust immunoreactivity was observed toward peptide 19 (Pep19), derived from HSP60 expressed by P. gingivalis (PgHSP60) showing a “epitope spreading” pattern, the unfurling of an autoimmune response specific to an antigen to different epitopes, in both groups.86 Here, HSPD1 is linked to type 1 diabetes mellitus.