Positive donor and negative recipient cytomegalovirus status is a detrimental factor for long-term renal allograft survival

Low-Dose vs Standard-Dose Valganciclovir for Cytomegalovirus Prophylaxis After Kidney Transplantation: A Single-Center Retrospective Analysis

BACKGROUND

Prophylactic administration of valganciclovir (VG) is an accepted method for the prevention of cytomegalovirus (CMV) infection after kidney transplantation (KTx). The standard dosage of oral VG is 900 mg/day, adjusted to renal function. There is growing evidence that low-dose 450 mg/day VG might be safe and effective. We compared low-dose vs standard-dose prophylaxis after KTx in a single-center follow-up study.

METHODS

Data from 603 renal transplantations at a single center were retrospectively analyzed (2011-2014, 12-month follow-up). Recipients with donor IgG positive-recipient IgG positive (D+/R+), (D+/R-), and (D-/R+) CMV serostatus were routinely treated with 450 mg/day VG for 3 months. Based on the same prophylactic dose, patients could be categorized into two groups according to their postoperative renal function: those receiving standard-dose VG due to a lower estimated glomerular filtration rate (eGFR) (average eGFR<60 mL/min/1.73 m2) and those receiving low-dose VG due to higher eGFR (average eGFR>60 mL/min/1.73 m2).

RESULTS

Estimated glomerular filtration rate-based VG serum alterations significantly affected the risk of CMV infection with a higher incidence in higher VG levels (standard-dose: 357 patients, CMV: 33 cases (9.2 %); low-dose: 246 patients, CMV: 10 cases (4.1%). The occurrence of known risk factors: serologic risk distribution and rate of induction therapy were not statistically different between the 2 groups. Treatment of an acute rejection episode influenced the infection rate significantly in the standard-dose group. As a side effect of prophylaxis, leucopenia (<3G/L) was 2.46 times higher in standard-dose vs low-dose group.

CONCLUSION

Low-dose VG administration is safe and non-inferior to the standard dose in the prophylaxis of CMV infection after KTx.

HLA-E Polymorphism Determines Susceptibility to BK Virus Nephropathy after Living-Donor Kidney Transplant

Human leukocyte antigen (HLA)-E is important for the regulation of anti-viral immunity. BK polyomavirus (BKPyV) reactivation after kidney transplant is a serious complication that can result in BKPyV-associated nephropathy (PyVAN) and subsequent allograft loss. To elucidate whether HLA-E polymorphisms influence BKPyV replication and nephropathy, we determined the HLA-E genotype of 278 living donor and recipient pairs. A total of 44 recipients suffered from BKPyV replication, and 11 of these developed PyVAN. Homozygosity of the recipients for the HLA-E*01:01 genotype was associated with the protection against PyVAN after transplant (p = 0.025, OR 0.09, CI [95%] 0.83-4.89). Considering the time course of the occurrence of nephropathy, recipients with PyVAN were more likely to carry the HLA-E*01:03 allelic variant than those without PyVAN (Kaplan-Meier analysis p = 0.03; OR = 4.25; CI (95%) 1.11-16.23). Our findings suggest that a predisposition based on a defined HLA-E genotype is associated with an increased susceptibility to develop PyVAN. Thus, assessing HLA-E polymorphisms may enable physicians to identify patients being at an increased risk of this viral complication.

IL-23 plasma level is strongly associated with CMV status and reactivation of CMV in renal transplant recipients

Background

Cytomegalovirus seropositivity is an independent risk factor for atherosclerosis in patients with ESRD. Donor CMV seropositivity is associated with higher graft loss. Dendritic cells, macrophages and Th17 lymphocytes are defined as producers of IL-23. IL-23 is thought to be involved in the promotion of Th17 cell polarization. Latent CMV-induced Th17 might be involved in the pathogenesis of CMV infection in patients with ESRD. We aimed to evaluate associations of Th17-dependent cytokines with ESRD, CMV status and post-transplant outcome in kidney transplantation.

Results

IL-21 plasma levels were similar in patients and healthy controls (p = 0.47), whereas IL-9 (p = 0.02) and IL-23 (p < 0.0001) levels were significantly higher in ESRD patients. CMV-seronegative (p = 0.002) and –seropositive (p < 0.001) patients had significantly higher IL-23 plasma levels than controls. CMV-seropositive patients showed excessively higher IL-23 (p < 0.001) plasma levels than CMV-seronegative patients. Patients with post-transplant CMV reactivation had higher IL-23 plasma levels than patients without CMV reactivation (p = 0.025).

Conclusions

Our results indicate that latent CMV induces IL-23. IL-23 might be an inflammatory mediator of latent CMV infection in patients with ESRD and predisposes patients for post-transplant CMV reactivation.

Post-transplant infections now exceed acute rejection as cause for hospitalization: a report of the NAPRTCS

Newer immunosuppressive agents have dramatically reduced the rates of acute graft rejection (AR) over the last decade but may have exacerbated the problem of post-transplant infections (PTI). We analyzed data from the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) to determine the risks of hospitalization from PTI vs. AR in the years 1987-2000. For patients transplanted in 1987, the AR-associated hospitalization rate exceeded the equivalent hospitalization rate for PTI at both early (1-6 months) and later time points (6-24 months). In contrast, for patients transplanted in the year 2000, the PTI-associated hospitalization rate was twice that for AR-associated hospitalization during each time period. During the first two years post-transplant, rates of AR hospitalization trended significantly downwards (p < 0.001) while rates of PTI-associated hospitalization stayed constant. In the 6-24-month time period post-transplant, the risk of bacterial and viral infection-related hospitalization rose significantly from 1987 to 2000 (p < 0.001 for trend by transplant year). We conclude that the causes of hospitalization at all times up to 24 months post-transplant, including the critical early 6 months, have shifted away from AR to PTI.

Resource utilization among kidney transplant recipients

BACKGROUND

Hospitalization consumes a significant portion of the end-stage renal disease (ESRD) program, which includes kidney transplant recipients. Identification of kidney transplant recipients at risk of increased resource utilization could lead to appropriate interventions to attenuate the complications related to kidney transplant, which may reduce resource utilization.

METHODS

This retrospective cohort study of kidney transplant recipients was performed to identify risk factors for hospital utilization. The study population consisted of patients who received kidney transplant at our center between October 1990 and September 1999 and were followed in the outpatient clinic.

RESULTS

Of the 220 patients, 171 (78%) were hospitalized during a median follow-up of 36 months. The number of hospitalizations, hospital days, and outpatient visits per patient-year at risk were 1.1, 6.3, and 21.6, respectively. Infection episodes were the leading cause of hospitalization. In a multivariate regression analysis, cytomegalovirus (CMV)-positive status of donor (RR 1.58; 95% CI 1.15, 2.18) and a higher number of hospital days during the transplant hospitalization (RR 1.10 per 7 days increase; 95% CI 1.03, 1.19) were associated with a higher risk of hospitalization, while higher serum albumin (RR 0.84 per 0.5 g/dL increase; 95% CI 0.73, 0.97), higher hematocrit (RR 0.95 per 1% increase; 95% CI 0.92, 0.98), higher glomerular filtration rate (GFR) (RR 0.91 per 10 mL/min/1.73 m2; 95% CI 0.85, 0.99), and an increased interval since transplant (RR 0.84 per 6 months increase; 95% CI 0.75, 0.93) were associated with a lower risk of hospitalization. CMV-positive status of the donor (RR 1.11; 95% CI 1.00, 1.21) and presence of cardiovascular disease (RR 1.12; 95% CI 1.00, 1.24) were associated with a higher risk of outpatient visits, while Caucasian race (RR 0.82; 95% CI 0.73, 0.94), higher serum albumin (RR 0.88 per 0.5 g/dL increase; 95% CI 0.84, 0.93), higher hematocrit (RR 0.96 per 1% increase; 95% CI 0.95, 0.97), and an increased interval since transplant (RR 0.79 per 6 months increase; 95% CI 0.76, 0.83) were associated with a lower risk of outpatient visits.

CONCLUSION

Identification of risk factors associated with increase resource utilization among kidney transplant recipients could aid in the development of targeted interventions to improve clinical and economic outcomes.