Causes of late transplant failure in cyclosporine-treated kidney allograft recipients

Plasma high-sensitivity C-reactive protein measured prior to transplant is related to prediabetes in first-year kidney transplant recipients: A single-center cross-sectional study in Vietnam

AIM

To determine the rate of prediabetes among and the pre-transplant plasma high-sensitivity C-reactive protein (hs-CRP) value predictive of prediabetes in patients during their first year post-living donor kidney transplant.

METHODS

A total of 538 patients underwent living donor kidney transplantation between January 2018 and December 2020, 413 of whom met the inclusion criteria for this study. All patients underwent oral glucose tolerance tests (OGTTs) with 75 g glucose/200 mL solution, starting 3 months post-transplant and repeating the test every 3 months for the first year. Clinical and paraclinical indicators and plasma hs-CRP concentrations were quantified the day prior to the transplant. Prediabetes was diagnosed according to the American Diabetes Association 2018 criteria as a 2-h OGTT result between 140 mg/dL (7.8 mmol/L) and 199 mg/dL (11.0 mmol/L).

RESULTS

The rate of prediabetes among the study subjects was 38.3 % (158/413). Body mass index (BMI) and pre-transplant plasma triglycerides, high-density lipoprotein cholesterol (HDLC), and hs-CRP levels were related factors predictive of prediabetes in patients within the first year post-kidney transplant based on multivariate logistic regression and receiver operative characteristic curve models. Hs-CRP was the factor with the best predictive value (area under the curve = 0.89; p < 0.001).

CONCLUSIONS

Pre-transplant plasma hs-CRP levels were a good predictor of prediabetes in the first year post-living donor kidney transplant.

Longitudinal study of human polyomaviruses viruria in kidney transplant recipients

INTRODUCTION

Immunosuppression after kidney transplantation (KTx) exposes recipients to Human Polyomaviruses (HPyVs) infections, whose natural history is still misunderstood.

METHODS

Allograft biopsies, and urine from 58 donor-recipient pairs were collected before KTx (T0) and 1 (T1), 15 (T2), 30 (T3), 60 (T4), 90 (T5), 180 (T6), 270 (T7), 360 (T8), and 540 (T9) days after transplant. Specimens were tested for JC (JCPyV) and BK (BKPyV), by quantitative Real-Time PCR. The course of post-KTx HPyVs viruria, and the association between JCPyV viruria in recipients and donors, were evaluated.

RESULTS

HPyVs were detected in 3/58 (5.2%) allograft biopsies. HPyVs viruria was present in 29/58 (50%) donors and 41/58 (70.7%) recipients. JCPyV DNA was detected in 26/58 (44.8%) donors and 25/58 recipients (43.1%), 19 of whom received kidney from JCPyV positive donor, whereas BKPyV genome was detected in 3 (5.2%) donors and 22 (37.9%) recipients. The median time of JCPyV, and BKPyV first episode of replication was 1, and 171 days post KTx, respectively. At T0, JCPyV viruria of donors was associated with increased risk of JCPyV replication post-KTx; recipients with JCPyV positive donors showed lower risk of BKPyV replication post-KTx.

CONCLUSIONS

The results suggested that JCPyV may be transmitted by allograft, and that its replication post KTx might prevent BKPyV reactivation. Future investigation regarding correlation between chronic exposure to immunosuppressive agents and HPyVs urinary replication are warranted.

Diabetic Kidney Disease in Post-Transplant Diabetes Mellitus: Causes, Treatment and Outcomes

Kidney transplant recipients are a unique subgroup of chronic kidney disease patients due to their single functioning kidney, immunosuppressive agent usage, and long-term complications related to transplantation. Post-transplant diabetes mellitus (PTDM) has a significant adverse effect on renal outcomes in particular. As transplantations enable people to live longer, cardiovascular morbidity and mortality become more prevalent, and PTDM is a key risk factor for these complications. Although PTDM results from similar risk factors to those of type 2 diabetes, the conditions differ in their pathophysiology and clinical features. Transplantation itself is a risk factor for diabetes due to chronic exposure to immunosuppressive agents. Considering current evidence, this article describes the risk factors, pathogenesis, diagnostic criteria, prevention strategies, and management of PTDM. The therapeutic options are discussed regarding their safety and potential drug-drug interactions with immunosuppressive agents.

Prevalence and Risk Factors of Abnormal Glucose Metabolism and New-Onset Diabetes Mellitus after Kidney Transplantation: A Single-Center Retrospective Observational Cohort Study

Background and objectives: New-onset diabetes after transplantation (NODAT) represents a primary cause of morbidity and allograft loss. We assessed prevalence and risk factors for NODAT in a population of Italian kidney transplant (KT) recipients. Methods: Data from 522 KT performed between January 2004 and December 2014 were analyzed. Participants underwent clinical examination; blood and urine laboratory tests were obtained at baseline, one, six, and 12-month of follow-up to detect glucose homeostasis abnormalities and associated metabolic disorders. An oral glucose tolerance test (OGTT) was performed at six months in 303 subjects. Results: Most patients were Caucasian (82.4%) with a mean age of 48 ± 12 years. The prevalence of abnormal glucose metabolism (AGM) and NODAT was 12.6% and 10.7%, respectively. Comparing characteristics of patients with normal glucose metabolism (NGM) to those with NODAT, we found a significant difference in living donation (16.6% vs. 6.1%; p = 0.03) and age at transplant (46 ± 12 vs. 56 ± 9 years; p = 0.0001). Also, we observed that patients developing NODAT had received higher cumulative steroid doses (1-month: 1165 ± 593 mg vs. 904 ± 427 mg; p = 0.002; 6-month:2194 ± 1159 mg vs. 1940 ± 744 mg; p = 0.002). The NODAT group showed inferior allograft function compared to patients with NGM (1-year eGFR: 50.1 ± 16.5 vs. 57 ± 20 mL/min/1.73 m2; p = 0.02). NODAT patients were more likely to exhibit elevated systolic blood pressure and higher total cholesterol and triglyceride levels than controls. Conclusions: The prevalence of NODAT in our cohort was relatively high. Patient age and early post-transplant events such as steroid abuse are associated with NODAT development.

Case Report: Splenic Irradiation for the Treatment of Chronic Active Antibody-Mediated Rejection in Kidney Allograft Recipients With De Novo Donor-Specific Antibodies

Chronic active antibody-mediated rejection (AMR) in renal transplantation is usually refractory to current conventional treatment with rituximab, plasmapheresis (PP), and intravenous immunoglobulins (IVIG). Splenic irradiation has been reported to be effective in the rescue of early severe acute AMR after kidney transplantation; however, its effect in chronic active AMR has not been reported to date. In order to reduce donor-specific antibody (DSA) and prevent the progression of chronic AMR, we used repetitive low-dose splenic irradiation, together with rituximab and PP/IVIG, in two living-related kidney transplant recipients with pathologically diagnosed chronic active AMR and the presence of long-term class II-de novo DSA. DSA monitoring and repeated renal biopsy revealed significantly reduced DSA levels as well as alleviated glomerulitis and peritubular capillaritis in both patients after treatment, and these therapies may have played a role in delaying the progression of chronic AMR. Although DSA levels in both patients eventually rebounded to some extent after treatment, serum creatinine increased slowly in one patient during the 16-month follow-up period and remained stable in the other during the 12-month follow-up period. Given the poor efficacy of conventional treatment at present, splenic irradiation may still be one of the treatment options for chronic active AMR.

New-Onset Diabetes after Kidney Transplantation

New-onset diabetes mellitus after transplantation (NODAT) is a frequent complication in kidney allograft recipients. It may be caused by modifiable and non-modifiable factors. The non-modifiable factors are the same that may lead to the development of type 2 diabetes in the general population, whilst the modifiable factors include peri-operative stress, hepatitis C or cytomegalovirus infection, vitamin D deficiency, hypomagnesemia, and immunosuppressive medications such as glucocorticoids, calcineurin inhibitors (tacrolimus more than cyclosporine), and mTOR inhibitors. The most worrying complication of NODAT are major adverse cardiovascular events which represent a leading cause of morbidity and mortality in transplanted patients. However, NODAT may also result in progressive diabetic kidney disease and is frequently associated with microvascular complications, eventually determining blindness or amputation. Preventive measures for NODAT include a careful assessment of glucose tolerance before transplantation, loss of over-weight, lifestyle modification, reduced caloric intake, and physical exercise. Concomitant measures include aggressive control of systemic blood pressure and lipids levels to reduce the risk of cardiovascular events. Hypomagnesemia and low levels of vitamin D should be corrected. Immunosuppressive strategies limiting the use of diabetogenic drugs are encouraged. Many hypoglycemic drugs are available and may be used in combination with metformin in difficult cases. In patients requiring insulin treatment, the dose and type of insulin should be decided on an individual basis as insulin requirements depend on the patient's diet, amount of exercise, and renal function.

Viral Genomic Characterization and Replication Pattern of Human Polyomaviruses in Kidney Transplant Recipients

Human Polyomavirus (HPyV) infections are common, ranging from 60% to 100%. In kidney transplant (KTx) recipients, HPyVs have been associated with allograft nephropathy, progressive multifocal leukoencephalopathy, and skin cancer. Whether such complications are caused by viral reactivation or primary infection transmitted by the donor remains debated. This study aimed to investigate the replication pattern and genomic characterization of BK Polyomavirus (BKPyV), JC Polyomavirus (JCPyV), and Merkel Cell Polyomavirus (MCPyV) infections in KTx. Urine samples from 57 KTx donor/recipient pairs were collected immediately before organ retrieval/transplant and periodically up to post-operative day 540. Specimens were tested for the presence of BKPyV, JCPyV, and MCPyV genome by virus-specific Real-Time PCR and molecularly characterized. HPyVs genome was detected in 49.1% of donors and 77.2% of recipients. Sequences analysis revealed the archetypal strain for JCPyV, TU and Dunlop strains for BKPyV, and IIa-2 strain for MCPyV. VP1 genotyping showed a high frequency for JCPyV genotype 1 and BKPyV genotype I. Our experience demonstrates that after KTx, HPyVs genome remains stable over time with no emergence of quasi-species. HPyVs strains isolated in donor/recipient pairs are mostly identical, suggesting that viruses detected in the recipient may be transmitted by the allograft.