Kinesis of cellular immune response to persistent infection with BK virus after renal transplantation / 中华器官移植杂志

ABSTRACT

Objective To analyze and discuss the dynamics of cellular immune response to persistent infection with BK virus after renal transplantation.Methods The recipients of renal transplantation in our center were selected and BK virus load in urine and blood was regularly observed.The victims of persistent infection with BK virus (defined as two successive positive results of BK virus load in urine or blood) were followed up and peripheral blood mononuclear cells (PBMCs) were collected for mixed cultivation with overlapping peptide pool,which contained peptide fragments (VP1,VP2,VP3,LT-Ag and st-Ag) extracted from BK virus.Flow cytometry was used to examine the in vitro proliferation of IFN-γ/IL-2/TNF-ininduced T cells and analyze the dynamics of cellular immune response to BK virus.Results A total of 46 recipients of renal transplantation were enrolled and 6 victims of persistent viruria were identified.Of the 6 victims,3 were complicated with persistent viremia,and 2 were diagnosed as BK virus nephropathy by biopsy,presenting with persistent viruria and viremia.The victims of persistent BK viremia after renal transplantation showed a significantly decreasing trend in cellular immune response to 5 BKV-specific proteins,according to the proliferation of TNF-γ/IL-2/TNF-α-induced T cells.However,this trend was not observed in the victims of persistent BK viruria.Conclusion At the stage of viremia,the victims of BKV infection after renal transplantation have seriously inhibited specific immune response to BKV.Thus,if the antiviral mechanisms are not restored in time,these recipients suffering persistent viremia are prone to virus nephropathy (BKVN),delayed graft function,and even graft loss.