BK Virus Infection After Renal Transplantation:the Risk Factors And Analysis Of Immunohistochemical Factors On BK Virus Associated Allograft Nephropathy

The epidemiological study of BK virus infection and analysis of risk factors in renal transplant recipientsObjective:BK Virus(BKV)infection has become one of the main complications in renal transplant recipients with the newer,more potent imunosuppressive agents.However,there are few centers focus on the epidemiological study of BK virusinfection and risk factors in Chinese population after renal transplantation.Methods:Renal transplant recipients who had received the detection of BKV DNA load in urine and blood samples in Nanjing General Hospital between June 2015 and July 2016 were selected,while dialysis patients and healthy living donors as control group.To discuss the epidemiological study of BKV infection in Chinese population after renal transplantation,and analyze whether the clinical data,postoperative complications and immunosuppressive regimen of renal transplant recipients have effect on BKV infection or not.Results:The positive rate of BKV DNA in urine samples of renal transplant recipients was 19.9%,of which the positive rate of BKV DNA in blood samples was 1.3%at the same time.That of dialysis patients and healthy living donors in urine samples was 6.3%,4.2%respectively,while these two groups were not found BKV DNA in blood samples.The BKV DNA positive rate in urine samples of renal transplant recipients was significantly higher than that of dialysis patients,as well as healthy living donors(P<0.001),but that of the latter two groups was similar(P=0.842).Univariate analysis shown postoperative pulmonary infection,acute rejection and tacrolimus(FK506)were associated with BKV infection in renal transplant recipients,while the gender,age,diabetes,(delayed graft function,DGF),Cyclosporine(CsA),and mycophenolate mofetil(MMF)were not.Furthermore,multivariate regression analysis also shown postoperative pulmonary infection(OR[95%CI],3.468[1.227-9.802];P =0.019),acute rejection(OR[95%CI],2.645[1.142-6.127];P=0.023),and FK506(OR[95%CI],2.408[1.104-5.254];P=0.027)were associated with BKV infection.Conclusions:The incidence of BKV infection in renal transplant recipients increases significantly.Postoperative pulmonary infection,acute rejection and immunosuppressive scheme based on FK506 are risk factors leading to BKV infection in renal transplantation.The analysis of Immunohistochemical factors on BK virus allograft nephropathyObjective:To investigate the immunohistological features of different stages BK virus allograft nephropathy(BKVAN).Methods:Fifty-three renal transplant recipients with pathologically confirmed BKVAN were selected in this retrospective study.According to the third edition of the American society of transplantation infection guidelines,12 were mild BKVAN(Stage A),22 were moderate(Stage B),and 19 case were severe(Stage C).The differences of CD4+,CD8+,CD20+,CD138+,CD68+ cells and interleukn-2 receptor(IL-2R)expressed in renal allograft biopsy and HLA-DR expressed in renal allograft tubular epithelial cell were observed among the three groups.Results:The levels of CD4+,CD8+,CD20+,CD138+,CD68+cells and IL-2R expressed in renal allograft biopsy and HLA-DR expressed in renal allograft tubular epithelial cell all were positive.Furthermore,the expression of the above factors were increased with the progress of BKVAN.The levels of CD4+,CD20+,CD 13 8+ and CD68+ cells were significantly increased in severe group compared to mild group(P<0.01),while the difference of CD8+,IL-2R or HLA-DR among the three groups were not statistically significant.Conclusions:Renal allograft damage caused by BKVAN involved T,B lymphocyte and mononuclear macrophage mediated immune responses.The increase of CD4+?CD20+?CD 13 8+ and CD68+ cells in renal allograft biopsy were the main factors causing BKVAN progression.