T Tu um mo ou ur r n ne ec cr ro os si is s f fa ac ct to or r--α g ge en ne e e ex xp pr re es ss si io on n b by y a al lv ve eo ol la ar r m ma ac cr ro op ph ha ag ge es s i in n h hu um ma an n l lu un ng g a al ll lo og gr ra af ft t r re ec ci ip pi ie en nt t w wi it th h r re ec cu ur rr re en nc ce e o of f s sa ar rc co oi id do os si is s ABSTRACT: Recurrence of sarcoidosis in lung allografts is an interesting model to study the pathogenesis of this disease. We report a case of sarcoidosis recurrence in a single lung allograft recipient 2 years after transplantation. The expression of tumour necrosis factor-α (TNF-α) gene by alveolar macrophages was monitored.The TNF-α gene was not expressed at the time of recurrence of sarcoidosis, but only later when prominent granulomas were observed.