Cross-sectional study of BK virus infection in pediatric kidney transplant recipients

BKV reactivation is associated with impaired graft function in adult kidney transplant patients. The clinical impact of BKV infection in the pediatric transplant population has not yet been fully evaluated. The objective of our study was to determine the prevalence of BKV infection in consecutive pediatric kidney transplant recipients in our center. Forty consecutive unselected pediatric kidney transplant recipients were studied. Mean age at screening was 15.6 +/- 5.3 yr and samples were obtained a median of 60.5 months after transplantation (3-123). BKV-DNA was analyzed in urine and plasma by qualitative nested-PCR. A review of the literature was performed. Prevalence of viruria and viremia was 50% and 12.5%, respectively. Viremia was associated with the presence of hematuria (p = 0.02). The mean creatinine level in children without BKV replication was 1.6 mg/dL, BKV viruria was 0.9 mg/dL, and BKV viremia was 0.8 mg/dL. A literature review showed that viruria and viremia were found in 28.2% and 8.5% of cases, respectively; BKV nephropathy was found in 3.8% and graft loss in 11% of the patients with BKV nephropathy and in 0.4% of the children studied. Recipient serostatus was the most important risk factor. The rate of BKV replication and nephropathy among pediatric kidney recipients is similar to that of adults, but the incidence of graft loss is significantly lower.     

Adenoviral disease in pediatric solid organ transplant recipients

Adenoviral disease in pediatric SOT recipients is emerging as an important viral pathogen, with serious consequences impacting morbidity, mortality and graft survival. The optimal diagnostic techniques, as well as therapy have yet to be established. This article reviews the current epidemiology of AdV in orthotopic liver, intestinal, cardiothoracic and renal transplant recipients. Issues related to diagnosis, notably the use of newer non-culture based viral detection methods and therapy, including anti-adenoviral agents and adoptive immunotherapy are discussed.     

Acute rejection episodes in pediatric renal transplant recipients with cytomegalovirus infection

Abstract:  CMV infection is the most important opportunistic virus infection after renal transplantation leading to increased patient mortality, graft loss, risk for acute rejection episodes and impaired renal function. The potential impact of prophylactic anti-viral therapy on long-term graft outcome is relevant. The aim of this study was to evaluate the incidence of CMV infection, its risk factors and long-term outcome in children after renal transplantation. 103 children (mean age 10.6 ± 5.3, range 1.6–22.0 yr) were monitored weekly for pp65 for the first 6–8 wk after renal transplantation, followed by a monthly monitoring for the first year. CMV infection occurred in 23/103 children (21.1%) with 10 patients (9.7%) developing CMV disease characterized by positive pp65 in the presence of organ involvement. The CMV R−/D+ and R+/D+ serostatus was significantly associated with an increased risk of CMV infection (p < 0.0001 and p = 0.009). 14/28 R−/D+ patients developed CMV infection despite prophylactic treatment with CMV hyperimmune globulin. The incidence of acute rejection episodes after or during CMV infection was significantly increased (p = 0.003) and the D+ serostatus was significantly associated with acute rejection episodes within the first year after transplantation (p = 0.006). In summary the overall incidence of CMV infection in this single center experience is 21.1%. The D+ serostatus represents a serious risk factor for both CMV infection and acute rejection episodes. In future the potential impact of different modalities of prophylactic anti-viral therapy on the prevention of acute rejection should be considered.     

Pilot study describing the use of pravastatin in pediatric renal transplant recipients

Renal transplant (Tx) recipients frequently develop hypercholesterolemia. Pravastatin (P) has been shown to be effective in adult renal Tx recipients, not only in reducing serum cholesterol, but possibly also in decreasing graft rejection. However, there are no data on the use of P in children following renal transplantation. We conducted a retrospective case-control study evaluating the safety and efficacy of P (10-20 mg/day) in reducing hypercholesterolemia, when used pre-emptively in the post-Tx period in seven children, compared with an historical control (C) group of nine children who had not received P. The two groups were comparable with respect to their demographics and in their pretransplant serum cholesterol. Compared with the C group, the mean serum cholesterol in the P group was lower at 3 months (159 mg/dL vs. 225 mg/dL), 6 months (134 mg/dL vs. 200 mg/dL), 9 months (134 mg/dL vs. 209 mg/dL), and 12 months (125 mg/dL vs. 195 mg/dL) (p < 0.005 for all, Student's two-tailed t-test). At 1 month only 43% of the P group had hypercholesterolemia compared with 67% of the controls; by 12 months this difference was even more significant (0% in the P group vs. 45% in the C group). None of the treated patients developed any adverse reactions. This study demonstrates that the pre-emptive use of P in pediatric renal Tx recipients appears to be effective in significantly reducing serum cholesterol. Whether this effect will translate into improved allograft and patient survival in the long term cannot be predicted at present and will require additional studies to evaluate.     

Urinary tract infections in pediatric renal transplant recipients – a two center risk factors study

Abstract:  UTI are common in renal Tx recipients and may significantly impact on the graft function. The aim of our study was to evaluate the prevalence, risk factors, and significance of UTI in Tx children. We performed a retrospective cross-sectional study of 76 Tx patients, median age at Tx was 13.4 yr. Twenty-one of 76 (28%) patients developed at least one UTI during the mean follow-up time of 3.3 ± 2.0 yr post-Tx. The first UTI occurred at a median of 160 days post-Tx. The RR of having UTI was significantly higher in patients with the primary diagnosis of obstructive uropathy (RR = 2.6, 95th CI = 1.1–6.0, p = 0.032), history of PN pre Tx (RR = 2.7, 95th CI = 1.3–5.4, p = 0.009) and pre Tx VUR (RR = 2.2, 95th CI = 1.1–4.5, p = 0.045). These three factors also significantly decreased the infection-free survival time to the first UTI. Most UTI caused reversible acute allograft dysfunction, but the long-term graft function could not be reliably assessed with SCr. In conclusion, UTI occurred in 28% of pediatric Tx recipients, mostly during the first year post-Tx despite antibiotic prophylaxis. The diagnosis of obstructive uropathy, history of UTI and VUR prior to Tx were significant risk factors.     

Multicenter trial of everolimus in pediatric renal transplant recipients: results at three year

Abstract:  There are few prospective clinical trials of mTOR inhibitors (or proliferation signal inhibitors) combined with CNI inhibitors in de novo pediatric renal transplantation. Results reported here are from a multicenter, open-label study in de novo pediatric renal transplant patients (≤16 yr), in which patients received everolimus with cyclosporine and corticosteroids for one yr, then entered an extension study for a further two yr. Nineteen patients completed the one-yr study, of whom three discontinued study medication. Fifteen of the remaining 16 patients entered the extension study, eight of whom were aged <10 yr (Group 1) and seven were aged 10–16 yr (Group 2). Mean daily dose of everolimus during the first 36 months was 1.53 mg/m² BSA. Biopsy-proven acute rejection occurred in three patients in Group 2 and in one patient in Group 1. Biopsy-proven chronic allograft rejection was reported in four patients (two in each age group). Graft survival at one yr was 100%; one patient in Group 2 lost their graft subsequently during the extension. For patients entering the extension, patient survival at three yr was 100%. There were three cases of viral infection, including one case of cytomegalovirus infection. At three yr, mean total cholesterol was 5.5 ± 0.8 m m /L (213 ± 31 mg/dL) and four patients received statin therapy. Mean serum creatinine at 36 months was 96 ± 36 μ m /L (1.1 ± 0.4 mg/dL). This is the first long-term prospective study to demonstrate that a regimen of everolimus, cyclosporine, and corticosteroids provides good efficacy, tolerability, and safety in de novo pediatric renal transplant patients.     

Alemtuzumab induction with tacrolimus monotherapy in 25 pediatric renal transplant recipients

ALA induction in transplantation has been shown to reduce the need for maintenance immunosuppression. We report the outcome of 25 pediatric renal transplants between 2007 and 2010 using ALA induction followed by tacrolimus maintenance monotherapy. Patient ages were 1–19 yr (mean 14 ± 4.1 yr). Time of follow‐up was 7–51 months (mean 26 ± 13 months). Tacrolimus monotherapy was maintained in 48% of patients, and glucocorticoids were avoided in 80% of recipients. Mean plasma creatinine and GFR at one yr post‐transplant were 0.88 ± 0.3 mg/dL and 104.4 ± 25 mL/min/1.73m², respectively. One, two, and three‐yr actuarial patient and graft survival rates were 100%. The incidence of early AR (<12 months after transplantation) was 12%, while the incidence of late AR (after 12 months) was 16%. Forty‐four percent of the recipients recovered normal, baseline renal function after an episode of AR, and 44% had persistent renal dysfunction (plasma creatinine 1.0–1.8 mg/dL). One graft was lost four yr after transplantation due to medication non‐compliance. Four (16%) patients developed BK or CMV infection. In our experience, ALA induction with tacrolimus monotherapy resulted in excellent short‐ and mid‐term patient and graft survival in low‐immunologic risk pediatric renal transplant recipients.     

JC polyomavirus‐specific antibody responses in pediatric kidney transplant recipients

BKPyV is widely recognized in KTRs, but little is known about rates of primary and secondary JCPyV exposure in pediatric KTRs. We evaluated JCPyV exposure in pediatric KTRs using antibody responses in the first 12 months post‐transplant. Of 46 children transplanted between 2009 and 2014, 6 lacked any samples for serologic testing, leaving 40 KTRs for study. JCPyV‐specific IgG and IgM antibodies were measured using a normalized VLP ELISA. Significant JCPyV exposure was defined as IgG seroconversion, increasing IgG levels of >0.5 nOD units, or IgM detection. Of 40 recipients (median age 3.2 years), 11 (27.5%) were seropositive, 20 (50%) seronegative for JCPyV‐IgG, while 9 (22.5%) had no specimen at the time of transplantation, but were confirmed as seronegative in post‐transplant samples. Of 29 (72.5%) at risk, JCPyV‐IgG seroconversion occurred in 15/29 (51.7%) including JCPyV‐IgM in 6 patients (20.7%). Two patients (6.9%) developed only JCPyV‐IgM. Among JCPyV‐IgG‐positive KTRs, six (12.5%) had significant IgG increases. Altogether 23 of 40 patients (57.5%) had serological evidence of primary or secondary JCPyV exposure. In these patients, kidney function tended to be lower during the 2 years of follow‐up, but only one patient lost the graft due to JCPyV nephropathy. Thus, JCPyV exposure is common in pediatric KTR and may present serologically as primary or secondary infection. Although only one case of JC‐PyVAN occurred, a trend toward lower renal function was seen. Dedicated studies of larger cohorts are warranted to define impact of JCPyV in pediatric KTR.     

Use of public health service increased risk kidneys in pediatric renal transplant recipients

With the opioid epidemic and expansion of “IR” classification, 25% of deceased donors are categorized PHS‐IR. Studies have assessed utilization of PHS‐IR organs among adults, but little is known about pediatric recipients. This retrospective cohort study from 2004‐2016 (IR period) aimed to: (a) assess IR kidney utilization patterns between adults and children; (b) identify recipient factors associated with transplant from IR donors among pediatric kidney recipients; and (c) determine geography's role in IR kidney utilization for children. The proportion of pediatric recipients receiving IR kidneys was significantly lower than adults (P < 0.001), even when stratified by donor mechanism of death (non‐overdose/overdose) and era. In mixed effects models accounting for clustering within centers and regions, older recipient age, later era (post‐PHS‐IR expansion), and blood type were associated with significantly higher odds of receiving an IR kidney (17 years era 5: OR 5.16 [CI 2.05‐13.1] P < 0.001; 18‐21 years era 5: OR 2.72 [CI 1.05‐7.06] P = 0.04; blood type O: OR 1.32 [CI 1.06‐1.64] P = 0.013). The median odds ratio for center within region was 1.77 indicating that when comparing two patients in a region, the odds of receiving an IR kidney were 77% higher for a patient from a center with higher likelihood of receiving an IR kidney. Utilization of PHS‐IR kidneys is significantly lower among pediatric recipients versus adult counterparts. More work is needed to understand the reasons for these differences in children in order to continue their access to this life‐prolonging therapy.     

A typology of non-adherence in pediatric renal transplant recipients

We reviewed 112 pediatric renal transplant recipients to document the rate of medication non-adherence (NA) and to examine the relationships between NA, comorbid psychiatric illness, and the outcome variables of acute and chronic rejection and graft loss. A total of 32.5% of subjects had clinically significant NA with treatment based on review of serum immunosuppressant levels. NA was found to be significantly related to acute and chronic rejection, and graft loss (p < 0.001). NA was also related to the presence of comorbid psychiatric illness (p < 0.001). Logistic regression indicated that NA was a significant predictor for acute and chronic rejection, while psychiatric illness predicted graft loss. Adolescents had significantly higher rates of NA as well as shorter intervals between transplant date and onset of NA when compared with child patients (p < 0.001). Physician ratings of the primary reasons for NA suggested that lack of parental supervision and parent-child conflict were the major factors related to NA.     

SRL-based immunosuppression vs. CNI minimization in pediatric renal transplant recipients with chronic CNI nephrotoxicity

Because calcineurin inhibitor (CNI)-induced nephrotoxicity contributes significantly to late renal allograft loss, sirolimus (SRL)-based, CNI-free maintenance immunosuppression has been advocated, but data in the pediatric population are scarce. We therefore analyzed the efficacy and safety of an SRL-based immunosuppressive regimen plus mycophenolate mofetil (MMF) and corticosteroids vs. CNI minimization (mean dose reduction by 39%) plus MMF and corticosteroids in 19 pediatric recipients with biopsy-proven CNI-induced nephrotoxicity in a single-center case-control study. In the SRL group, we observed, one yr after study entry, an improvement of glomerular filtration rate (GFR) by 10.3 +/- 3.0 mL/min/1.73 m2 (p < 0.05 vs. baseline) in seven of 10 patients and a stabilization in the remaining three, while in the CNI minimization group GFR improved by 17.7 +/- 7.1 mL/min/1.73 m2 (p < 0.05) in six of nine recipients and stabilized in the remaining three. No patient in either group experienced an acute rejection episode. The main adverse event under SRL therapy was a transient hyperlipidemia in 70% of patients. In pediatric renal transplant recipients with declining graft function because of CNI-induced nephrotoxicity, CNI withdrawal and switch to SRL-based therapy or CNI minimization are associated with a comparable improvement of GFR after 12 months of observation.     

Novel influenza (H1N1) infection in pediatric renal transplant recipients: a single center experience

In 2009, novel influenza A H1N1 caused significant morbidity and mortality worldwide, particularly in children. Because they are immunocompromised, pediatric transplant recipients are presumed to be at high risk. This study assessed epidemiological characteristics, presenting symptoms, and clinical course among pediatric renal transplant recipients with confirmed H1N1 infection. A retrospective review was conducted in renal transplant recipients followed at The Hospital for Sick Children (Toronto) who contracted H1N1 infection between June and November, 2009. Epidemiological, clinical, and laboratory features at presentation, and clinical course were analyzed. Of 59 children, 14 (23.7%) developed H1N1 infection. Children with H1N1 infection had undergone kidney transplantation more recently than their uninfected counterparts. The most common symptoms included fever (92.9%), cough (85.7%), headache (42.9%), and vomiting (42.9%). Fifty percent of patients required hospitalization, of median duration 3.0 (1.0-5.0) days. No child required intensive care treatment. Half the H1N1-infected children had acute renal dysfunction, with serum creatinine elevated >10% above basal values (median increase 21.6 [14.3-46.2]%). In five of the seven children, serum creatinine returned to baseline within two wk. These findings indicate that H1N1 influenza infection in pediatric kidney transplant recipients followed at our center was surprisingly mild, and produced no lasting sequelae.     

BK viral infection in an Australian pediatric renal transplant population

BK virus (BKV) is recognized as a significant cause of renal allograft dysfunction in adults, and there is growing awareness of its importance in the pediatric population. Eighteen pediatric renal transplant recipients and 18 age-matched controls were prospectively studied. Anti-BKV immunoglobulin G (IgG) and IgM titres were assayed in all subjects at entry to the study. Polymerase chain reaction (PCR) for BKV DNA was performed on urine and serum at entry, and prospectively tested again at 4, 8 and 12 months. Mean age +/- s.d. of transplant recipients and controls was 14.6 +/- 3.3 and 13.9 +/- 0.33 yr respectively [not significant (NS)]. Transplant patients were studied at a mean time of 5.6 +/- 4.2 yr post-transplant. 56% of transplant patients and 39% of controls were seropositive (+ve BKV IgG) (NS). Plasma BKV PCR was positive in one transplant patient (who also had positive urine PCR) and in none of the controls. The prevalence of positive urine PCR in transplant patients was greater than in controls (33% vs. 0%, p = 0.02). Positive urine BKV PCR was more commonly found in patients treated with mycophenolate than azathioprine (p = 0.04). We conclude that the prevalence of BKV seropositivity and viral activation in this Australian pediatric renal transplant population is similar to that reported in adult and pediatric populations in other countries. BK viruria was more common in children with greater immunosuppression, suggesting that this group is at higher risk of BKV induced nephropathy.     

Linear growth in pediatric renal transplant recipients receiving sirolimus

SRL is a potent macrolide immunosuppressive agent that can be used as maintenance therapy for prevention of rejection and avoidance of CNI nephrotoxicity. However, animal studies indicate that SRL may inhibit skeletal and muscle growth. We analyzed linear growth in 25 children, age 1-15 yr old, maintained on SRL to determine whether SRL is detrimental to linear growth. Height z-scores at baseline were compared with those at 24 months. We also compared linear growth in children receiving SRL to patients maintained on TAC. Height z-scores over 24 months did not significantly change in the SRL group as a whole. Z-scores improved in 13 of 25 patients (52%). Children with improved z-scores were significantly younger than patents who did not display improved growth: 6 ± 5 yr vs. 11 ± 4 yr (p < 0.05). Height z-scores in SRL and TAC-based patients were no different initially and at 24 months, and a similar number of patients in each group displayed improved height scores. Height z-scores improved in 52% of patients on SRL and occurred predominantly in younger patients for the initial 24 months of treatment. Linear growth in SRL patients was also similar to the results in TAC-based patients. Therefore, our data did not identify a significant adverse effect of SRL on growth.     

Induction therapy in pediatric kidney transplant recipients discharged with a triple drug immunosuppressive regimen

Sampaio MS, Poommipanit N, Kuo H‐T, Reddy PN, Cho YW, Shah T, Bunnapradist S. Induction therapy in pediatric kidney transplant recipients discharged with a triple drug immunosuppressive regimen.
Pediatr Transplantation 2010: 14:770–778. © 2010 John Wiley & Sons A/S. Abstract: We evaluated the effectiveness of induction therapy on transplant outcomes during 2004–2007 in the United States. We retrospectively reviewed OPTN/UNOS registry and selected kidney pediatric (<21‐yr) recipients that received no induction (NoIND), IL‐2RA, or rabbit anti‐THY and were discharged with a triple drug immunosuppressive maintenance regimen, including steroids. Of 2932 recipients, 20%, 36%, and 43% were in NoIND, THY, and IL‐2RA groups, respectively. The majority received tacrolimus (88%) and MMF (89%) at discharge. There was no association of induction with the risk of acute rejection even after adjusting for known cofounders. Compared to NoIND, IL2‐RA, but not THY, had a modest decrease (3%) in absolute rate of graft loss and was associated with a risk reduction ratio of 0.51 (95% CI, 0.31–0.84) in one‐yr graft loss. At three yr, no induction agent was associated with decreased graft loss. In conclusion, induction agents were used in 80% of pediatric kidney recipients discharged with a triple drug immunosuppressive maintenance regimen between 2004–2007 in the United States. Neither THY nor IL‐2RA was associated with reduced rejection episodes. The use of induction therapy was not associated with improvement in three‐yr graft survival.     

Cytomegalovirus transmission in pediatric renal transplant recipients during the window period

We report two CMV naïve children who received deceased donor renal transplants from a CMV IgG‐negative single donor. CMV IgG in both recipients and the donor were negative immediately prior to transplant. Both recipients had early recurrences of their original disease in their transplants, requiring multiple sessions of plasmapheresis. All blood products used were leukoreduced or CMV seronegative. A few days post‐transplant, both recipients developed significant positive CMV viremia. Both required initiation of oral valganciclovir. Case 1 responded to oral valganciclovir only while the case 2 had a delayed response to it and hence required intravenous ganciclovir with good response. When checked retrospectively, CMV IgM in the donor was positive along with positive CMV DNA PCR from the white cells. Here we describe a very unusual scenario of CMV transmission in two pediatric renal transplant recipients from a single donor during the CMV window period.