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Background: Some studies have suggested mizoribine (MZR) could inhibit the replication of BK polyomavirus (BKPyV). The purpose of this study was to explore whether conversion from mycophenolate mofetil (MMF) to MZR in the early stages of BKPyV infection can improve kidney allograft prognosis., Methods: Twenty-one kidney transplant recipients with BKPyV viruria/viremia and ten with BK polyomavirus-associated allograft nephropathy (BKPyVAN) received MZR conversion therapy were retrospectively identified. The clearance rate of urine and blood BKPyV DNA, change of serum creatinine (SCr), uric acid (UA), hemoglobin (HB), white blood cell (WBC), lymphocyte ratio, platelet (PLT), routine urinalysis, panel reactive antibody (PRA), and gastrointestinal disorders during follow-up of the 2 groups were evaluated and compared., Results: After MZR conversion therapy, the clearance rate of urine and blood viral load in BKPyV viruria/viremia group were 85.7 and 100 %, while that in BKPyVAN were 40 and 87.5 %, respectively. Stable SCr were observed in all cases of BKPyV viruria/viremia group, while that of BKPyVAN was only 40 % (P < 0.001) and one even progressed to end-stage renal disease. The results of routine urinalysis in the two groups showed no significant changes before and after MZR conversion therapy. However, in BKPyV viruria/viremia group, four cases developed acute rejection and one had positive PRA-II but no donor specific antibody, requiring conversion back to MMF. Hyperuricemia was the common adverse effect of MZR., Conclusions: Conversion from MMF to MZR could help clear BKPyV infection. As compared to BKPyVAN, patients who underwent initiation of MZR conversion therapy in the early stages of BKPyV infection maintained stable allograft function. Prospective studies with larger sample size are needed to ascertain this preliminary finding., (© 2021. The Author(s).)

Objectives: To investigate the immunohistochemical features of different stages of BK virus allograft nephropathy (BKVN) and further elucidate the underlying immunological mechanism involved in the evolution of BKVN. Methods: Fifty-two renal transplant recipients with biopsy proven BKVN were retrospectively selected. According to the third edition of the American Society of Transplantation Infection guidelines, 10 patients were categorized as having mild BKVN (stage A), 25 were moderate (stage B) and 17 were severe (stage C). The differential infiltrations of CD3+ (T lymphocytes), CD4+ (helper T lymphocytes), CD8+ (cytotoxic T lymphocytes), CD20+ (B lymphocytes), CD68+ (macrophages) and CD138+ (plasma cells) cells and the expression of interleukin-2 receptor (IL-2R) and human leukocyte antigen DR (HLA-DR) were compared among the three groups. Results: CD3+, CD4+, CD8+, CD20+, CD138+ and CD68+ cells infiltrations, IL-2R and HLA-DR expression were positive in the BKVN patients. Moreover, with increasing stages of BKVN, the numbers of positively stained inflammatory cells and the expression of IL-2R were significantly increased in the severe group compared to the mild group, whereas no statistically significant differences were observed with regard to HLA-DR expression. Eosinophil and neutrophil infiltration could also be observed in moderate to advanced BKVN. Conclusion: Renal allograft damage caused by BKVN involved T lymphocyte-, B lymphocyte- and mononuclear macrophage-mediated immune responses. Inflammatory cell infiltrations in the renal allograft were probably the driving force for BKVN progression. Additionally, eosinophils and neutrophils may be involved in the pathophysiological mechanism of BKVN.

Objectives: BK virus (BKV) infection has become one of the main complications in renal transplant recipients (RTRs) with the arrival of newer potent immunosuppressive agents. However, reports on the epidemiology of BKV infection and risk factors in Chinese population after renal transplantation are scarce., Methods: From June 2015 to July 2016, living-donor renal transplant recipients (LDRTRs) who routinely received the quantitative BKV DNA testing of urine and plasma samples using quantitative real-time polymerase chain reaction (PCR) for the first time after transplantation were selected, while dialysis patients and healthy living donors during that period served as controls. Potential variables were compared and analyzed using logistic regression model multivariate analysis to assess the BKV infection related factors in LDRTRs., Results: Among the 52 LDRTRs identified, BKV DNA was detected in 16 urine samples (30.8%), significantly higher than that of dialysis patients (6.3%) and healthy living donors (4.2%) (p < .001). Nevertheless, no statistically significant difference wax noted between the latter two groups in urine samples (p = .842). Meanwhile, BKV DNA detection in blood samples was all negative in the three groups. Univariate analysis shown tacrolimus (Tac) trough level and lymphocyte percentage were associated with BKV infection in LDRTRs. Multivariate regression analysis also showed Tac trough level (HR, 1.644; p = .03), lymphocyte percentage (HR, 0.878; p = .026) were associated with BKV infection in LDRTRs., Conclusions: In Chinese population, the incidence of BKV infection increased significantly after living-donor renal transplantation. Significantly increased Tac trough level and decreased lymphocyte percentage might be the risk factors for BKV infection in LDRTRs.

Background: Transplant glomerulopathy (TG) represents a major cause of long-term allograft failure and is the leading cause of overall post-transplant proteinuria. The extent to which histopathologic features predicts prognostication is uncertain.Methods: A single-center retrospective cohort with biopsy-proven TG was investigated. Renal biopsies were scored according to Banff 2017. The primary outcome was death-censored graft failure defined as return to dialysis or estimated glomerular filtration rate (eGFR) decreased to <15 mL/min/1.73 m2. The prognostic significance of clinical and histopathologic parameters was determined using Cox proportional hazards models.Results: Data from 180 cases were available for analysis with a median follow-up of 5.0 (2.6-8.2) years. In multivariable models, ci + ct score (HR 3.1; 95% CI 2.0-4.9), cg score (HR 1.7; 95% CI 1.1-2.8), eGFR (HR 2.1; 95% CI 1.4-3.2) and proteinuria (HR 2.4; 95% CI 1.6-3.7) were independent predictors of the primary outcome. Mesangial Immunoglobulin A deposition did not significantly affect allograft survival. The only significant pathologic factors for the severity of proteinuria were cg and g + ptc (adjusted R2 = 0.46) as determined by multivariable stepwise linear regression analysis.Conclusions: Severe ci + ct and cg at biopsy were predictors of unfavorable allograft prognosis in TG patients even after taking into consideration clinical characteristics. Histologic severity of cg and g + ptc was significantly associated with clinical proteinuria. [ABSTRACT FROM AUTHOR]