Cytopenia Occurrence in Kidney Transplant Recipients Within Early Post-transplant Period

Pitfalls in Valganciclovir Prophylaxis Dose Adjustment Based on Renal Function in Kidney Transplant Recipients

Valganciclovir (VGC) is administered as prophylaxis to kidney transplant recipients (KTR) CMV donor (D)+/recipient (R)- and CMV R+ after thymoglobulin-induction (R+/TG). Although VGC dose adjustments based on renal function are recommended, there is paucity of real-life data on VGC dosing and associations with clinical outcomes. This is a retrospective Swiss Transplant Cohort Study-embedded observational study, including all adult D+/R- and R+/TG KTR between 2010 and 2020, who received prophylaxis with VGC. The primary objective was to describe the proportion of inappropriately (under- or over-) dosed VGC week-entries. Secondary objectives included breakthrough clinically significant CMV infection (csCMVi) and potential associations between breakthrough-csCMVi and cytopenias with VGC dosing. Among 178 KTR, 131 (73.6%) patients had ≥2 week-entries for the longitudinal data of interest and were included in the outcome analysis, with 1,032 VGC dose week-entries. Overall, 460/1,032 (44.6%) were appropriately dosed, while 234/1,032 (22.7%) and 338/1,032 (32.8%) were under- and over-dosed, respectively. Nineteen (14.5%) patients had a breakthrough-csCMVi, without any associations identified with VCG dosing (p = 0.44). Unlike other cytopenias, a significant association between VGC overdosing and lymphopenia (OR 5.27, 95% CI 1.71-16.22, p = 0.004) was shown. VGC prophylaxis in KTR is frequently inappropriately dosed, albeit without meaningful clinical associations, neither in terms of efficacy nor safety.

Cytopenias in pediatric kidney transplant recipients: preceding factors and clinical consequences

BACKGROUND

Kidney trans plantation is associated with secondary complications, including the risk of developing posttransplant cytopenias. This study aimed to evaluate the characteristics, identify predictors, and assess the management and consequences of cytopenias in the pediatric kidney transplant population.

METHODS

This is a single-center retrospective analysis of 89 pediatric kidney transplant recipients. Possible factors preceding cytopenias were compared with the goal of recognizing predictors for posttransplant cytopenias. Posttransplant neutropenias were analyzed for the total study period and separately for the period beyond 6 months posttransplant (late neutropenias), to rule out confounding influences of induction and initial intensive therapy.

RESULTS

Sixty patients (67%) developed at least one episode of posttransplant cytopenia. All episodes of posttransplant thrombocytopenias were mild or moderate. Posttransplant infections and graft rejection were found to be significant predictors for thrombocytopenia (HR 6.06, 95% CI 1.6-22.9, and HR 5.82, 95% CI 1.27-26.6, respectively). A total of 30% of posttransplant neutropenias were severe (ANC ≤ 500). Pretransplant dialysis and posttransplant infections were significant predictors for late neutropenias (HR 11.2, 95% CI 1.45-86.4, and HR 3.32, 95% CI 1.46-7.57, respectively). Graft rejection occurred in 10% of patients with cytopenia, all following neutropenia, within 3 months from cytopenia appearance. In all such cases, mycophenolate mofetil dosing had been held or reduced prior to rejection.

CONCLUSIONS

Posttransplant infections are substantial contributors to developing posttransplant cytopenias. Preemptive transplantation appears to reduce risk of late neutropenia, the accompanying reduction in immunosuppressive therapy, and the ensuing risk of graft rejection. An alternative response to neutropenia, possibly using granulocyte colony stimulating factor, may diminish graft rejection. A higher resolution version of the Graphical abstract is available as Supplementary information.

Effects of Induction Therapy on Graft Functions in Terms of Immunologic Risk

BACKGROUND

Advances in immunosuppressive therapies and surgical techniques have led to a significant reduction in the incidence of rejection within 1 year after kidney transplantation. Immunologic risk is an important factor affecting graft functions and guiding the clinician in the selection of induction therapy. The aim of this study was to investigate graft functions based on serum creatinine levels, Chronic Kidney Disease Epidemiology Collaboration (CKD- EPI) and proteinuria levels, frequency of leukopenia, cytomegalovirus (CMV) and BK virus polymerase chain reaction (PCR) positivity in patients with low and high immunologic risk.

MATERIAL AND METHODS

This retrospective study included 80 renal recipients. Recipients were divided into 2 groups: patients at low immunologic risk who received basiliximab only and those with high immunologic risk who received low-dose (1.5 mg/kg for 3 days) antithymocyte globulin and basiliximab.

RESULTS

No significant differences were observed between the 2 risk groups in terms of first, third, sixth, and 12th-month creatinine levels, CKD-EPI, proteinuria levels, leukopenia frequency, and CMV and BK virus PCR positivity.

CONCLUSION

One-year graft survivals did not differ significantly between these 2 treatment modalities. The combined use of low-dose antithymocyte globulin and basiliximab in the induction treatment of patients with high immunologic risk seems promising in terms of graft survival, leukopenia frequency, and CMV and BK virus PCR positivity.

Neutropenia in pediatric solid organ transplant

Neutropenia is generally defined as an absolute neutrophil count in the circulation of less than 1500/mm³ and occurs in up to 25%-30% of pediatric solid organ transplant recipients (SOT) within the first year after transplantation. In the SOT population, neutropenia is most often a result of drug-induced bone marrow suppression but can also be secondary to viral infection, nutritional deficiencies, lymphoproliferative infiltrate, and inherited causes. Outcomes for patients with neutropenia vary by degree of neutropenia and type of solid organ transplant. Management of neutropenia should begin by addressing the underlying cause, including reducing or removing medications when appropriate, treating infections, and addressing nutrient deficiencies; however, consultation with an experienced pediatric hematologist and use of granulocyte colony-stimulating factor (G-CSF) may be helpful in some cases. Overall, data on clinical outcomes for G-CSF use remain limited, but observational studies may support its use in patients with infections or severe neutropenia.

Transplant of Kidneys From Hepatitis C Virus-Positive Donors To Hepatitis C Virus-Negative Recipients: A Retrospective Study and Systematic Review

OBJECTIVES

Kidneys from hepatitis C virus-positive donors were often discarded due to the lack of an effective treatment for hepatitis C virus. However, the advent of direct-acting antivirals has facilitated great progress for treatment of hepatitis C virus, providing additional opportunities for patients waiting for kidney transplant. We explored the feasibility and safety of kidney transplant from hepatitis C virus- positive donors to hepatitis C virus-negative recipients in combination with direct-acting antiviral therapy.

MATERIALS AND METHODS

This was a single-center retrospective study of 7 recipients of hepatitis C virus- positive kidneys from June 2018 to June 2021. All recipients were treated with sofosbuvir/velpatasvir for 12 weeks after kidney transplant. The primary recipients' outcome was achievement of sustained viral eradication at 12 weeks after treatment, and follow-up secondary outcomes were kidney function recovery, liver function, and adverse drug reactions. We reviewed previous studies, from 2017 to 2022, to analyze achievement of sustained viral eradication at 12 weeks after treatment, recipient and graft survival, and adverse event of kidney transplant from a hepatitis C virus-positive donor to a hepatitis C virus-negative recipient.

RESULTS

Median follow-up time was 71 weeks (range, 56-183 weeks). All recipients achieved sustained viral eradication at 12 weeks after treatment, and their kidney function recovered without severe liver damage or adverse drug reactions. Previous studies suggested that transplant of hepatitis C virus-positive donor kidneys is safe and feasible when combined with direct-acting antiviral therapy. However, details regarding optimal duration of treatment and directacting antiviral regimen remain undetermined, so prospective randomized studies are warranted.

CONCLUSIONS

Our study further confirms that kidney transplant from hepatitis C virus-positive donors to hepatitis C virus-negative recipients is safe and feasible with direct-acting antiviral treatment. Grafts from hepatitis C virus-infected donors may be effective to resolve the problem of kidney shortage.

Kidney Transplantation From Deceased Donors With Vaccine-induced Immune Thrombocytopenia and Thrombosis: An Updated Analysis of the UK Experience

BACKGROUND

The emergence and attendant mortality of vaccine-induced immune thrombocytopenia and thrombosis (VITT) as a consequence of vaccination against severe acute respiratory syndrome coronavirus 2 have resulted in some patients with VITT being considered as deceased organ donors. Outcomes after kidney transplantation in this context are poorly described. Because the disease seems to be mediated by antiplatelet factor 4 antibodies, there is a theoretical risk of transmission via passenger leukocytes within the allograft.

METHODS

We analyzed the experience of kidney transplantation from donors with VITT in the United Kingdom between January and June 2021. We followed-up all recipients of kidney-only transplants from donors with VITT to detect major postoperative complications or features of disease transmission and assess graft survival and function.

RESULTS

There were 16 kidney donors and 30 single kidney transplant recipients in our study period. Of 11 preimplantation biopsies, 4 showed widespread glomerular microthrombi. After a median of 5 mo, patient and graft survival were 97% and 90%, respectively. The median 3-mo estimated glomerular filtration rate was 51 mL/min/1.73 m 2 . Two recipients had detectable antiplatelet factor 4 antibodies but no evidence of clinical disease after transplantation. Major hemorrhagic complications occurred in 3 recipients, all of whom had independent risk factors for bleeding, resulting in the loss of 2 grafts. The involvement of VITT could not be completely excluded in one of these cases.

CONCLUSIONS

The UK experience to date shows that favorable outcomes are possible after kidney transplantation from donors with VITT but highlights the need for ongoing vigilance for donor-related complications in these patients.

Predictors and Complications of Post Kidney Transplant Leukopenia

BACKGROUND

Leukopenia occurs frequently following kidney transplantation and is associated with adverse clinical outcomes including increased infectious risk. In this study we sought to characterize the causes and complications of leukopenia following kidney transplantation.

METHODS

In a cohort of adult patients (≥18 years) who underwent kidney transplant from Jan 2006-Dec 2017, we used univariable Cox proportional Hazards models to identify predictors of post-transplant leukopenia (WBC < 3500 mm³). Factors associated with post-transplant leukopenia were then included in a multivariable backwards stepwise selection process to create a prediction model for the outcome of interest. Cox regression analyses were subsequently used to determine if post-transplant leukopenia was associated with complications.

RESULTS

Of 388 recipients, 152 (39%) developed posttransplant leukopenia. Factors associated with leukopenia included antithymocyte globulin as induction therapy (HR 3.32, 95% CI 2.25-4.91), valganciclovir (HR 1.84, 95% CI 1.25-2.70), tacrolimus (HR 3.05, 95% CI 1.08-8.55), prior blood transfusion (HR 1.17 per unit, 95% CI 1.09- 1.25), and donor age (HR 1.02 per year, 95% CI 1.00-1.03). Cytomegalovirus infection occurred in 26 patients with leukopenia (17.1%). Other than cytomegalovirus, leukopenia was not associated with posttransplant complications.

CONCLUSION

Leukopenia commonly occurred posttransplant and was associated with modifiable and non-modifiable pretransplant factors.

Drug-Induced Hematological Cytopenia in Kidney Transplantation and the Challenges It Poses for Kidney Transplant Physicians

Drug-induced hematological cytopenia is common in kidney transplantation. Various cytopenia including leucopenia (neutropenia), thrombocytopenia, and anemia can occur in kidney transplant recipients. Persistent severe leucopenia or neutropenia can lead to opportunistic infections of various etiologies. On the contrary, reducing or stopping immunosuppressive medications in these events can provoke a rejection. Transplant clinicians are often faced with the delicate dilemma of balancing cytopenia and rejection from adjustments of immunosuppressive regimen. Differentials of drug-induced cytopenia are wide. Identification of culprit medication and subsequent modification is also challenging. In this review, we will discuss individual drug implicated in causing cytopenia and correlate it with corresponding literature evidence.