BACKGROUND With maintenance azathioprine+prednisone and in biopsies performed exceptionally earlier than in the 4th week (1966-1984, 476 cadaveric kidney transplantations), prevalence of obliterative arteriopathy (OA, transmural arteritis, 4/III/v3 Banff classif.) was 22.1%, with graft loss by rejection within 6 mos. in 89.4%. The aim of this analysis was to study prevalence and prognostic importance of the former and of further early vascular lesions in subjects with maintenance cyclosporin A using biopsies performed as early as in the 1st week. RESULTS In a retrospective study on 449 transplantation (1987-92, cyclosporin A+prednisone+azathioprine, 64.7% grafts histologically--mostly repeatedly--examined), prevalence and prognostic classification (A-good, B-uncertain, C-poor prognosis) in recipients with OA, with cellular arteriopathy (CA, intimal arteritis, 4/II-III/v2-v3 Banff classif.) and with minimal arterial lesions (MZ) were assessed. Prevalence of OA was found to be 7.1% transplantations, with graft loss by rejection within 6 mos. in 71.9%, and with A:C proportion 25.0%: 62.5%. CA was found in 5.1% and showed A:C proportion 34.7%: 34.7%; in 6/13 cases with repeated histology, OA was later encountered, which is a strong point against its humoral pathogenesis. Prevalence of MZ was 10.9%, with A:C proportion 40.8: 4.1%. CONCLUSIONS Both OA and CA are related to rejection, while the etiology of MZ remains to be clarified. With cyclosporine, prevalence of OA markedly decreased and its prognosis somewhat improved; secondary prevention is possible when an early diagnosis (early and repeated biopsies) is done and immediate treatment (antilymphocyte globulins) started.