The purpose of our pilot study was to evaluate the short-and long-term efficacy of T-lymphocyte depletion in the management of patients with refractory, systemic autoimmune diseases. Nine patients with severe, therapy-resistant autoimmune diseases were subjected to T-cell depletion procedure using polyclonal anti-T-cell antibodies combined with peroral administration of azathioprine and/or cyclosporine. The proband group consisted of 4 patients with systemic lupus erythematosus, 3 with progressive systemic sclerosis, and 2 with rheumatoid arthritis. Administration of polyclonal anti-T-cell antibodies was performed at a single occasion via a central venous catheter during 9-10 days. Immunological analyses of T-cell phenotypes and function and assessment of organ function (kidneys, lungs, bone-marrow) has been performed prospectively in all the patients studied. This treatment resulted in prompt and long-lasting (mean follow-up time: 25.6 months) improvement of autoimmune hemolytic anemia, glomerulonephritis, lung fibrosis, skin and joint involvements in the majority of cases. Adverse effects of this treatment included two episodes of infection (E. coli and Cytomegalovirus) and three cases of serum sickness, and were all easily managed. We suggest that this treatment modality adopted from transplant rejection therapy could be employed in cases of severe autoimmune diseases unresponsive to regular immunosuppressive treatment.