Absence of human T-lymphotrophic virus type I in patients with systemic lupus erythematosus

The role of the human T-cell lymphotropic/leukaemia virus type I (HTLV-I) in the pathogenesis of autoimmune diseases of unknown cause, such as systemic lupus erythematosus (SLE), multiple sclerosis (MS) or Sjogren's syndrome (SS) has been discussed extensively. We have investigated whether SLE is in any way associated with exogenous HTLV-I. Using enzyme immunoassay (EIA), we found no seroreactivity against HTLV-I antigens in any of 24 SLE patients under investigation. Using a radioimmunoprecipitation assay (RIPA), there was also no expression of retroviral tax-protein demonstrable in 24 individuals with SLE. DNA preparations of peripheral blood cells, as well as isolated CD4- and CD8-positive cells, were examined for HTLV-I sequences (pol-, env-, gag-, LTR- and tax-region) using polymerase chain reaction (PCR). We were unable to demonstrate any specific HTLV-I PCR products in SLE specimens. Our data suggest that exogenous HTLV-I is not involved in the pathogenesis of SLE.