Screening of Sera for Anti-htlv-i Antibodies

Serum antibodies against human T cell leukaemia virus type I (HTLV-I) were investigated in 12 patients by four methods: indirect immunoperoxidase staining, indirect immunofluorescence, enzyme linked immunosorbent assay (ELISA), and strip radioimmunoassay based on the Western blotting assay. Seven patients had systemic lupus erythematosus (SLE) and five various autoimmune diseases with one or more circulating autoantibodies. Serum samples from three patients were found to be HTLV-I-positive by the ELISA assay and sera from five patients showed a non-specific reaction by indirect immunofluorescence. These sera were negative when tested by indirect immunoperoxidase staining and Western blotting assay. All four methods gave positive results when tested with samples from 19 HTLV-I carriers and 16 patients with adult T cell leukaemia. Indirect immunoperoxidase staining and Western blotting assay are probably useful and more specific assays for the detection of anti-HTLV-I antibodies in samples from patients with autoimmune diseases. Several methods to detect antibodies against HTLVI-namely, indirect immunofluorescence using fixed MT-I cells,' membrane immunofluorescence, solid phase immunocompetition assay,23 enzyme linked immunosorbent assay (ELISA),4 gelatin particle agglutination,5 and strip radioimmunoassay, based on the Western blotting assay,6 have been reported. There are still difficulties, however, in detecting specific antiHTLV-I antibodies in patients with autoimmune disease with circulating autoantibodies. Indeed, with indirect immunofluorescence and ELISA assays it is not always easy to exclude a non-specific reaction. In this study we investigated the presence ofantibodies to HTLV-I in the sera from patients with systemic lupus erythematosus and other autoimmune diseases by several of the above methods and a new immunoperoxidase technique. Accepted for publication 4 August 1987 Material and methods PATIENTS WITH AUTOIMMUNE DISEASE Sera from seven patients with systemic lupus erythematosus and five patients with progressive systemic sclerosis (n = 1), idiopathic thrombocytopenic purpura (n = 1), Sj6gren's syndrome (n = 1), polymyositis, (n = 1), and rheumatoid arthritis (n = 1), treated in Kumamoto (an area where the incidence of HTLV-I infection is high) were studied. All were women aged between 28 and 67 years who had one or. more circulating autoantibodies (anti-DNA, antimitochondria, thyroid autoantibodies etc). As positive controls, sera from 16 patients with adult T cell leukaemia (ATL) and 19 HTLV-I carriers were tested by indirect immunofluorescence, and sera from 26 healthy subjects were used as negative controls. SCREENING OF SERA FOR ANTI-HTLV-I