[Unusual infections in transplantation].

The occurrence of infections in organ transplantation is one of the most significant determinants of transplant outcome, because it is the most common life-threatening complication of long-term immunosuppressive therapy. Recently, besides the well-known direct effect of infections, other relevant biochemical factors such as cytokines, chemokines and growth factors have been considered. Aim of this review is to deal with the infections by mainly considering the unusual consequences of several infectious diseases like malignancies, graft loss and atherosclerosis. The number of patients affected by malignancies is increasing in all registries. Viral pathogens play a pathophysiological role in the development of the most frequent malignancies after solid organ transplantation. In some cases viruses act by altering cell transformation. Moreover, some pathogens may contribute to global immunosuppression and work together to promote oncogenesis. The viral load surveillance is recommended in the prevention of malignancies. The BK virus nephropathy in renal transplant recipients is emerging as an unusual consequence of graft loss. In this paper we examine the risk factors, the clinical characteristics and especially the diagnostic tools and treatments actually available. The third unusual consequence is the transplant vascular sclerosis, a multifactorial late complication of solid organ transplantation. The transplant vascular sclerosis has emerged as an important limitation in long-term graft survival. Several epidemiological, clinical and therapeutic interventional studies have shown how several potential contributing etiologic factors, such as Chlamydia and CMV infection, have been identified as being definitely associated with the development of transplant vascular sclerosis.