Interventions for BK virus infection in kidney transplant recipients.
BK virus-associated nephropathy (BKVAN), caused by infection with or reactivation of BK virus, remains a challenge in kidney transplantation. Screening is recommended for all kidney transplant recipients. For those with clinically significant infection, reduction of immunosuppression is the cornerstone of management. There is no specific antiviral or immunomodulatory therapy sufficiently effective for routine use.
This review aimed to examine the benefits and harms of interventions for BK virus infection in kidney transplant recipients.
We searched the Cochrane Kidney and Transplant Register of Studies up to 5 September 2024 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.
All randomised controlled trials (RCTs) and cohort studies investigating any intervention for the treatment or prevention of BKVAN for kidney transplant recipients.
Two authors independently assessed the study quality and extracted data. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes and mean difference (MD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.
Twelve RCTs (2669 randomised participants) were included. Six studies were undertaken in single centres, and six were multicentre studies; two of these were international studies. The ages of those participating ranged from 44 to 57 years. The length of follow-up ranged from three months to five years. All studies included people with a kidney transplant, and three studies included people with signs of BK viraemia. Studies were heterogeneous in terms of the type of interventions and outcomes assessed. The overall risk of bias was low or unclear. Intensive screening for the early detection of BK viraemia or BK viruria prevents graft loss (1 study, 908 participants: RR 0.00, 95% CI 0.00 to 0.05) and decreases the presence of decoy cells and viraemia at 12 months (1 study, 908 participants: RR 0.06, 95% CI 0.03 to 0.11) compared to routine care (high certainty evidence). No other outcomes were reported. Compared to placebo, fluoroquinolones may slightly reduce the risk of graft loss (3 studies, 393 participants: RR 0.37, CI 0.09 to 1.57; I2 = 0%; low certainty evidence), probably makes little or no difference to donor-specific antibodies (DSA), may make little or no difference to BK viraemia and death, had uncertain effects on BKVAN and malignancy, but may increase the risk of tendonitis (2 studies, 193 participants: RR 5.66, CI 1.02 to 31.32; I2 = 0%; low certainty evidence). Compared to tacrolimus (TAC), cyclosporin (CSA) probably makes little or no difference to graft loss and death, may make little or no difference to BKVAN and malignancy, but probably decreases BK viraemia (2 studies, 263 participants: RR 0.61, 95% CI 0.26 to 1.41; I2 = 38%) and probably reduces the risk of new-onset diabetes after transplantation (1 study, 200 participants: RR 0.41, 95% CI 0.12 to 1.35) (both moderate certainty evidence). Compared to azathioprine, mycophenolate mofetil (MMF) probably makes little or no difference to graft loss and BK viraemia but probably reduces the risk of death (1 study, 133 participants: RR 0.43, 95% CI 0.16 to 1.16) and malignancy (1 study, 199 participants: RR 0.43, 95% CI 0.16 to 1.16) (both moderate certainty evidence). Compared to mycophenolate sodium (MPS), CSA has uncertain effects on graft loss and death, may make little or no difference to BK viraemia, but may reduce BKVAN (1 study, 224 participants: RR 0.06, 95% CI 0.00 to 1.20; low certainty evidence). Compared to immunosuppression dose reduction, MMF or TAC conversion to everolimus or sirolimus may make little or no difference to graft loss, BK viraemia or BKVAN (low certainty evidence). TAC conversion to sirolimus probably results in more people having a reduced BK viral load (< 600 copies/mL) than immunosuppression reduction (1 study, 30 participants: RR 1.31, 95% CI 0.90 to 1.89; moderate certainty evidence). Compared to MPS, everolimus had uncertain effects on graft loss and BK viraemia, may reduce BKVAN (1 study, 135 participants: 0.06, 95% CI 0.00 to 1.11) and may increase the risk of death (1 study, 135 participants: RR 3.71, 95% CI 0.20 to 67.35) (both low certainty evidence). Compared to CSA, everolimus may make little or no difference to BK viraemia, has uncertain effects on graft loss and BKVAN, but may increase the risk of death (1 study, 185 participants: RR 3.71, 95% CI 0.42 to 32.55; low certainty evidence). Compared to immunosuppression reduction, the leflunomide derivative FK778 may make little or no difference to graft loss, probably results in a greater reduction in plasma BK viral load (1 study, 44 participants: -0.60 copies/µL, 95% CI -1.22 to 0.02; moderate certainty evidence), but had uncertain effects on BKVAN and malignancy. Aggravated hypertension may be increased with KF778 (1 study, 46 participants: RR 8.23, 95% CI 0.50 to 135.40; low certainty evidence). There were no deaths in either group.
Intense monitoring early after transplantation for BK viruria and BK viraemia is effective in improving BK virus infection outcomes as it helps with early detection of the infection and allows for a timely reduction in immunosuppression reduction. There is insufficient evidence to support any other intervention for BK virus infection in kidney transplant recipients.
Wajih Z
,Karpe KM
,Walters GD
《Cochrane Database of Systematic Reviews》
Serum and urine nucleic acid screening tests for BK polyomavirus-associated nephropathy in kidney and kidney-pancreas transplant recipients.
BK polyomavirus-associated nephropathy (BKPyVAN) occurs when BK polyomavirus (BKPyV) affects a transplanted kidney, leading to an initial injury characterised by cytopathic damage, inflammation, and fibrosis. BKPyVAN may cause permanent loss of graft function and premature graft loss. Early detection gives clinicians an opportunity to intervene by timely reduction in immunosuppression to reduce adverse graft outcomes. Quantitative nucleic acid testing (QNAT) for detection of BKPyV DNA in blood and urine is increasingly used as a screening test as diagnosis of BKPyVAN by kidney biopsy is invasive and associated with procedural risks. In this review, we assessed the sensitivity and specificity of QNAT tests in patients with BKPyVAN.
We assessed the diagnostic test accuracy of blood/plasma/serum BKPyV QNAT and urine BKPyV QNAT for the diagnosis of BKPyVAN after transplantation. We also investigated the following sources of heterogeneity: types and quality of studies, era of publication, various thresholds of BKPyV-DNAemia/BKPyV viruria and variability between assays as secondary objectives.
We searched MEDLINE (OvidSP), EMBASE (OvidSP), and BIOSIS, and requested a search of the Cochrane Register of diagnostic test accuracy studies from inception to 13 June 2023. We also searched ClinicalTrials.com and the WHO International Clinical Trials Registry Platform for ongoing trials.
We included cross-sectional or cohort studies assessing the diagnostic accuracy of two index tests (blood/plasma/serum BKPyV QNAT or urine BKPyV QNAT) for the diagnosis of BKPyVAN, as verified by the reference standard (histopathology). Both retrospective and prospective cohort studies were included. We did not include case reports and case control studies.
Two authors independently carried out data extraction from each study. We assessed the methodological quality of the included studies by using Quality Assessment of Diagnostic-Accuracy Studies (QUADAS-2) assessment criteria. We used the bivariate random-effects model to obtain summary estimates of sensitivity and specificity for the QNAT test with one positivity threshold. In cases where meta-analyses were not possible due to the small number of studies available, we detailed the descriptive evidence and used a summative approach. We explored possible sources of heterogeneity by adding covariates to meta-regression models.
We included 31 relevant studies with a total of 6559 participants in this review. Twenty-six studies included kidney transplant recipients, four studies included kidney and kidney-pancreas transplant recipients, and one study included kidney, kidney-pancreas and kidney-liver transplant recipients. Studies were carried out in South Asia and the Asia-Pacific region (12 studies), North America (9 studies), Europe (8 studies), and South America (2 studies).
blood/serum/plasma BKPyV QNAT The diagnostic performance of blood BKPyV QNAT using a common viral load threshold of 10,000 copies/mL was reported in 18 studies (3434 participants). Summary estimates at 10,000 copies/mL as a cut-off indicated that the pooled sensitivity was 0.86 (95% confidence interval (CI) 0.78 to 0.93) while the pooled specificity was 0.95 (95% CI 0.91 to 0.97). A limited number of studies were available to analyse the summary estimates for individual viral load thresholds other than 10,000 copies/mL. Indirect comparison of thresholds of the three different cut-off values of 1000 copies/mL (9 studies), 5000 copies/mL (6 studies), and 10,000 copies/mL (18 studies), the higher cut-off value at 10,000 copies/mL corresponded to higher specificity with lower sensitivity. The summary estimates of indirect comparison of thresholds above 10,000 copies/mL were uncertain, primarily due to a limited number of studies with wide CIs contributed to the analysis. Nonetheless, these indirect comparisons should be interpreted cautiously since differences in study design, patient populations, and methodological variations among the included studies can introduce biases. Analysis of all blood BKPyV QNAT studies, including various blood viral load thresholds (30 studies, 5658 participants, 7 thresholds), indicated that test performance remains robust, pooled sensitivity 0.90 (95% CI 0.85 to 0.94) and specificity 0.93 (95% CI 0.91 to 0.95). In the multiple cut-off model, including the various thresholds generating a single curve, the optimal cut-off was around 2000 copies/mL, sensitivity of 0.89 (95% CI 0.66 to 0.97) and specificity of 0.88 (95% CI 0.80 to 0.93). However, as most of the included studies were retrospective, and not all participants underwent the reference standard tests, this may result in a high risk of selection and verification bias.
urine BKPyV QNAT There was insufficient data to thoroughly investigate both accuracy and thresholds of urine BKPyV QNAT resulting in an imprecise estimation of its accuracy based on the available evidence.
There is insufficient evidence to suggest the use of urine BKPyV QNAT as the primary screening tool for BKPyVAN. The summary estimates of the test sensitivity and specificity of blood/serum/plasma BKPyV QNAT test at a threshold of 10,000 copies/mL for BKPyVAN were 0.86 (95% CI 0.78 to 0.93) and 0.95 (95% CI 0.91 to 0.97), respectively. The multiple cut-off model showed that the optimal cut-off was around 2000 copies/mL, with test sensitivity of 0.89 (95% CI 0.66 to 0.97) and specificity of 0.88 (95% CI 0.80 to 0.93). While 10,000 copies/mL is the most commonly used cut-off, with good test performance characteristics and supports the current recommendations, it is important to interpret the results with caution because of low-certainty evidence.
Maung Myint T
,Chong CH
,von Huben A
,Attia J
,Webster AC
,Blosser CD
,Craig JC
,Teixeira-Pinto A
,Wong G
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《Cochrane Database of Systematic Reviews》
Uniform Graft-versus-Host Disease Prophylaxis using Post-Transplantation Cyclophosphamide, Methotrexate, and Cyclosporine following Peripheral Blood Hematopoietic Stem Cell Transplantation from Matched and Haploidentical Donors for Transfusion-Dependent T
Although the survival of patients with transfusion-dependent thalassemia (TD-TM) is reportedly inferior after haploidentical hematopoietic stem cell transplantation (HSCT), the heterogeneity of transplantation approaches in studies suggests the need to assess the effect of conditioning regimen on matched and haploidentical transplantation outcomes. A novel post-transplantation cyclophosphamide (PTCy)-based approach for patients with TD-TM undergoing haploidentical HSCT was reported in our prior study. Here we aimed to retrospectively evaluate the real-world efficacy and safety of graft-versus-host disease (GVHD) prophylaxis in patients with TD-TM after HSCT from matched donors and haploidentical donors (HIDs). In this retrospective multicenter study, among 238 patients with TD-TM who underwent HSCT, 160 underwent peripheral blood HSCT, using uniform GVHD prophylaxis with PTCy, methotrexate, and cyclosporine, at member centers of the Bone Marrow Failure Working Group of Hunan Province between 2019 and 2023. The median age of the cohort at transplantation was 6 years (95% confidence interval [CI], 6 to 7 years). The 160 donors included 99 (61.9%) haploidentical family members, 13 matched sibling donors, and 48 matched or mismatched unrelated donors. The engraftment rate was 98.8% (95% CI, 96.1% to 97.7%). HSCT from HIDs had a lower risk of mixed chimerism (HR, .078; P = .022). Within 100 days after transplantation, 31 patients (19.6%; 95% CI, 14.0% to 26.3%) had grade II-IV acute GVHD (aGVHD), 9 of whom had grade III-IV aGVHD (5.7%; 95% CI, 2.9% to 10.1%). HIDs were significantly associated with a higher risk of grade II-IV aGVHD (HR, 3.973; P = .009). Nineteen patients (11.9%; 95% CI, 7.6% to 17.6%) developed late aGVHD after a median of 516 days (95% CI, 407 to 709 days). Twenty-six patients (16.5%; 95% CI, 11.3% to 22.8%) exhibited any 1 of the diagnostic, distinctive, or atypical features of chronic GVHD (cGVHD) according to the 2014 National Institutes of Health (NIH) criteria after a median of 690 days (95% CI, 496 to 902 days). Among these 26 patients, 7 had NIH-defined cGVHD, 14 had only 1 distinctive sign with no histologic evidence, and 5 had only atypical cGVHD signs. Of the 26 patients, 5 were classified with overlap syndrome. Of 21 patients classified with NIH-defined and potential cGVHD, 3 had moderate cGVHD and 1 had severe cGVHD. Logistic regression analyses identified that grade II-IV aGVHD independently predicted subsequent cGVHD (HR, 3.920; P = .006). The rates of cGVHD were similar in the matched donor and HID groups. Thalassemia-free survival (TFS) and event-free survival (EFS) were 97.5% (95% CI, 94.2% to 99.2%) and 90.6% (95% CI, 85.4% to 94.4%), respectively, after a median of 690 days (95% CI, 496 to 902 days). TFS rates were similar in the matched donor and HID groups (P = .549). The EFS rate was significantly higher in the matched donor group compared to the HID group (P = .033). Our study suggests that when PTCy-based uniform GVHD prophylaxis is administered, HSCT from matched donors and HIDs results in a low incidence of severe GVHD and treatment-related mortality with satisfactory survival.
Gong S
,Tian X
,Yang R
,Yang L
,Wang Z
,Yang K
,Chen K
,He X
,Deng W
,Yang X
,Lei M
,Fu B
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