The IDDMK_1,222 retrovirus is not detectable in either mRNA or genomic DNA from patients with type 1 diabetes

A new viral sequence (IDDMK_1,222) similar to the human endogenous retrovirus (HERV)-K10/K18 subfamilies has recently been isolated from the culture supernatants of leukocyte-infiltrated islets from two patients who died at the onset of type 1 diabetes. It was claimed that this endogenous retrovirus is expressed in patients with type 1 diabetes but not in healthy control subjects, suggesting an important role of the retrovirus in β-cell- specific autoimmunity that results in type 1 diabetes. However, despite exhaustive attempts involving identical and expanded methods of detection, we did not observe the IDDMK_1,222 viral sequence in genomic DNA, lymphocyte, or plasma RNA in any subject. Therefore, we believe that the vital sequence is not derived from an endogenous retrovirus and that a role for the retrovirus in the pathogenesis of type 1 diabetes must be reconsidered.