Human endogenous retrovirus with a high genomic sequence homology with IDDMK(1,2)22 is not specific for type I (insulin-dependent) diabetic patients but ubiquitous

Aims/hypothesis. It has been reported recently that a novel human endogenou s retroviral gene, insulin-dependent diabetes mellitus (IDDM)K(1,2)22, was expressed in the plasma of Type I diabetic patients but not in that of nond iabetic control subjects. This investigation was initiated to determine the specificity of the selective expression of IDDMK(1,2)22 in diabetic patien ts. Methods. We isolated the total RNA from the plasma and lymphocytes of 13 ne w onset Type I diabetic patients and 10 normal control subjects and amplifi ed it by reverse transcriptase polymerase chain reaction. We then determine d the presence of IDDMK(1,2)22 with a specific primer set, U3/R-poly(A), us ed in a recent report and the 5 'SAg/3 'SAg primer set recognizing the puta tive superantigen encoding the region of the IDDMK(1,2)22 envelope (env) ge ne. In addition, we carried out nested PCR of the U3/R-poly(A) polymerase c hain reaction product using U3N/R primers. Results. We found no difference in the presence of the polymerase chain rea ction products between diabetic patients and all nondiabetic subjects teste d. Sequencing of the U3/R-poly(A) polymerase chain reaction products showed that the exact sequence of IDDMK(1,2)22 was not present in any of the samp les tested, neither in the plasma of diabetic patients nor in that of nondi abetic control subjects. Endogenous retroviral sequences with 90-93 % seque nce homology to IDDMK(1,2)22 were, however, equally present in both the dia betic and nondiabetic subjects. Conclusion/interpretation. We conclude that a human endogenous retroviral g ene with high sequence homology with IDDMK(1,2)22 is not specific for diabe tic patients but, rather, is ubiquitous.