BK virus nephropathy is not always alone

BK Polyomavirus Infection and Risk Factors in Pediatric Patients Undergoing Kidney Transplant

OBJECTIVES

BK polyomavirus infection is a critical complication affecting graft survival after kidney transplant. We aimed to determine the frequency, the effect on graft function, and the risk factors of BK polyomavirus infection in pediatric kidney transplant patients.

MATERIALS AND METHODS

We retrospectively reviewed data of 144 pediatric patients (female/male: 67/77; 0-18 years of age) who received kidney transplants in the past 10 years at our center. Demographic/ laboratory data, kidney failure etiologies, donor types, and immunosuppressive treatments were recorded. Patients were grouped as those with and without BKV infection, with groups compared in terms of transplant age, sex, kidney failure etiology, donor type, immunosuppressive treatments, presence of ureteral stents, acute rejection episodes, accompanying viral infections, glomerular filtration rate, and graft loss rate.

RESULTS

Twelve patients (8.3%) had BK polyomavirus infection. All 12 patients had viruria (8.3%), 8 (5.5%) had viremia, and 4 (2.8%) had BK polyomavirus nephropathy. Two patients (1.4%) had graft loss because of BK polyomavirus nephropathy. When patients with and without infection were compared, no significant differences were found in terms of sex, transplant age, donor type, presence of a ureteral stent, acute rejection, graft loss, or immunosuppressive treatment (P > .05). Rates of congenital anomalies of the kidney and urinary tract were 30.3% and 66.6% in those without and with BK polyomavirus infection, respectively (P < .05). The group positive for BK polyomavirus had a significantly higher incidence of cytomegalovirus infection versus the group without infection (P < .05). Glomerular filtration rate values at years 1 and 3 were similar between groups (P > .05).

CONCLUSIONS

Frequency of BK polyomavirus nephropathy in pediatric patients undergoing kidney transplant in our center was consistent with data from other centers. Graft loss can be prevented by early detection and treatment through close periodic control and adequate evaluation of risk factors.

Endocarditis in kidney transplant recipients: a systematic review

Infective Endocarditis (IE) carries significant mortality. Bacteremia, which is a predisposing factor for IE, occurs more frequently in immunocompromised individuals. Interestingly, IE in kidney transplant recipients has not been adequately described. The aim of this study was to systematically review all published cases of IE in kidney transplant recipients and describe their epidemiology, microbiology, clinical characteristics, treatment and outcomes. A systematic review of PubMed (through 13^th December 2019) for studies providing epidemiological, clinical, microbiological as well as treatment data and outcomes of IE in kidney transplant recipients was performed. A total of 60 studies, containing data of 117 patients, were included in the analysis. The most common causative pathogens were gram-positive microorganisms in 57.4%, gram-negative microorganisms in 14.8%, fungi in 20%, while in 18.9% of cases, IE was culture-negative. Aortic valve was the most commonly infected valve followed by mitral, tricuspid and the pulmonary valve. Diagnosis was set with a transthoracic ultrasound in half the cases, followed by transesophageal ultrasound and autopsy. Fever was present in most cases, while embolic phenomena were noted in two out of five cases. Aminoglycosides, cephalosporins and aminopenicillins were the most commonly used antimicrobials, and surgical management was performed in one out of three cases. Clinical cure was noted in 60.9%, while overall mortality was 45.3%. To conclude, this systematic review thoroughly describes IE in kidney transplant recipients and provides information on epidemiology, clinical presentation, treatment and outcomes. Moreover, it identifies the emerging role of Enterococci, gram-negatives and fungi in IE in this population.

Transplant renal artery stenosis in a child with BK nephropathy

TRAS and BK nephropathy are known complications of RT, but the association between both has not been reported. A 2-year-old girl underwent a deceased donor renal transplant from a 20-year-old donor, along with bilateral native nephrectomies. She had a DGF due to a renal artery thrombus and required thrombectomy with re-anastomosis. Heparin and aspirin were used. Immunosuppressive agents included thymoglobulin, steroid, tacrolimus, and MMF. CMV and EBV DNA PCRs were negative, but she developed BK viremia at 2 months with stable allograft function. Immunosuppression was reduced, and leflunomide was initiated. Blood pressures were well controlled on low-dose amlodipine. Five months after RT, she presented with hypertensive emergency, following a respiratory infection, and required dialysis for oliguric acute kidney injury. Allograft biopsy showed evidence of BK nephropathy. Immunosuppression was further minimized. Doppler renal US and renal artery duplex studies were both suggestive of TRAS. Angiogram showed severe proximal anastomotic TRAS (>95% occlusion). PTA with stenting was done with immediate improvement in the blood flow and reduction in the pressure gradient. BPs and renal function normalized. Ten months post-RT, she remains normotensive with stable renal function and resolution of BK viremia. Although ureteral stenosis and nephropathy are known to occur with BK infection, TRAS is an interesting association and possibly suggest the tropism of BK virus to the vascular endothelial cells. Timely recognition and management of both is important to prevent uncontrolled hypertension and allograft dysfunction.

Risk factors and long-term outcomes of parvovirus B19 infection in kidney transplant patients

BACKGROUND

Parvovirus B19 is a small, non-enveloped, single-stranded DNA virus with a special affinity for the erythroid progenitor cells of the bone marrow. The first case of parvovirus B19 infection in a kidney transplant recipient (KTR) was reported in 1986. Data on the risk factors and specific clinical characteristics of parvovirus B19 infection remain insufficient.

METHODS

We screened 602 KTRs for parvovirus B19 infection using parvovirus B19 polymerase chain reaction (PCR) from January 1990 to April 2016, and the clinical characteristics of patients with positive results were compared to those of age- and gender-matched patients with negative PCR results.

RESULTS

A total of 39 KTRs tested positive for parvovirus B19, and they were compared to 78 age- and gender-matched patients among 563 KTRs who had negative PCR results. In all, 89.7% of positive cases were reported within the first year after kidney transplantation. In multivariate analyses, deceased-donor kidney transplantation (odds ratio [OR] 9.067, 95% confidence interval [CI] 1.668-49.275, P = .011), use of tacrolimus (OR 3.607, 95% CI 1.024-12.706, P = .046), PCR test within 1 year of kidney transplantation (OR 12.456, 95% CI 2.674-58.036, P = .001), and hemoglobin levels (OR 0.559, 95% CI 0.351-0.889, P = .014) showed significant correlations with parvovirus B19 infection. Graft survival did not differ between the two groups during the follow-up period of 111.68 ± 54.54 months (P = .685 by log-rank test).

CONCLUSION

The identification of factors related to positive parvovirus B19 PCR results may promote the early detection of parvovirus B19 infection. Further studies are needed to elucidate the characteristics of parvovirus B19 infection in kidney transplantation.