Significance of Perivascular Aggregates in Kidney Allografts: Evaluation of 1-Year Protocol Biopsies Using Recent Banff Classification

BACKGROUND

Perivascular aggregates (PVAs) often occur in kidney allografts; however, their significance needs to be re-evaluated in light of changes in the concept and criteria of allograft rejection.

METHODS

We reviewed 1-year protocol biopsies in 258 patients with kidney transplants to identify PVAs and concurrent pathology based on the Banff 2017 classification, including revised criteria for chronic active T-cell mediated rejection (CA-TCMR). We investigated the incidence of PVA, concurrent allograft lesions, diagnosis, and graft survival. No prisoners were used in this study, and no participants were coerced or paid.

RESULTS

We identified PVA in 81 biopsies (31.4%). The incidence of previous rejection (32.1% vs 12.4%, P= .0003) and total inflammation (1.3 ± 0.8 vs 0.6 ± 0.8, P < .0001), inflammation (0.7 ± 0.8 vs 0.2 ± 0.5, P < .0001), inflammation in the area of interstitial fibrosis and tubular atrophy (1.3 ± 1.2 vs 0.7 ± 0.9, P < .0001), tubulitis (1.4 ± 1.1 vs 0.6 ± 0.9, P < .0001), and interstitial fibrosis scores (1.2 ± 0.9 vs 0.9 ± 0.9, P= .01) were higher in PVA-positive compared with patients with PVA-negative. Diagnoses in the PVA-positive group revealed no rejection in 49.4%, CA-TCMR in 21.0%, borderline changes in 18.5%, and acute TCMR in 6.2%. CA-TCMR was more frequent in patients with PVA-positive (21.0% vs 4.0%, P < .0001). Graft survival was similar in both groups among all patients, no-rejection, any type of rejection, and CA-TCMR subgroups.

CONCLUSIONS

PVAs occur heterogeneously and are associated with previous rejection or concurrent CA-TCMR. The prognostic significance of PVAs in kidney transplantation is inconclusive, and further investigations are needed.

Granzyme K- and amphiregulin-expressing cytotoxic T cells and activated extrafollicular B cells are potential drivers of IgG4-related disease

BACKGROUND

IgG4-related disease (IgG4-RD), an example of a type I immune disease, is an immune-mediated fibrotic disorder characterized by dysregulated resolution of severe inflammation and wound healing. However, truly dominant or pathognomonic autoantibodies related to IgG4-RD are not identified.

OBJECTIVE

We sought to perform single-cell RNA sequencing and T-cell receptor and B-cell receptor sequencing to obtain a comprehensive, unbiased view of tissue-infiltrating T and B cells.

METHODS

We performed unbiased single-cell RNA-sequencing analysis for the transcriptome and T-cell receptor sequencing and B-cell receptor sequencing on sorted CD3+ T or CD19+ B cells from affected tissues of patients with IgG4-RD. We also conducted quantitative analyses of CD3+ T-cell and CD19+ B-cell subsets in 68 patients with IgG4-RD and 30 patients with Sjögren syndrome.

RESULTS

Almost all clonally expanded T cells in these lesions were either Granzyme K (GZMK)-expressing CD4+ cytotoxic T cells or GZMK+CD8+ T cells. These GZMK-expressing cytotoxic T cells also expressed amphiregulin and TGF-β but did not express immune checkpoints, and the tissue-infiltrating CD8+ T cells were phenotypically heterogeneous. MKI67+ B cells and IgD-CD27-CD11c-CXCR5- double-negative 3 B cells were clonally expanded and infiltrated affected tissue lesions. GZMK+CD4+ cytotoxic T cells colocalized with MKI67+ B cells in the extrafollicular area from affected tissue sites.

CONCLUSIONS

The above-mentioned cells likely participate in T-B collaborative events, suggesting possible avenues for targeted therapies. Our findings were validated using orthogonal approaches, including multicolor immunofluorescence and the use of comparator disease groups, to support the central role of cytotoxic CD4+ and CD8+ T cells expressing GZMK, amphiregulin, and TGF-β in the pathogenesis of inflammatory fibrotic disorders.

A Single-Center Retrospective Study of Re-Transplantation After Allograft Failure in Kidney Transplant Recipients

BACKGROUND

This study aimed to examine the outcomes of kidney retransplantation in patients with allograft failure at Kyushu University.

METHODS

We reviewed data from 1043 consecutive patients (including 1001 in a first kidney transplantation [KT] group and 42 in a second KT group) who had undergone KT alone at our institution between January 2008 and September 2022. We also studied immunologic risks and outcomes of patients who had undergone preoperative testing for KT at Kyushu University during the same period.

RESULTS

No patient received more than 2 transplants. Donor-specific anti-HLA antibody (DSA) had been detected in a greater percentage of patients in the second KT group than in the first (31% vs 11%, respectively; P < .001). There were no significant differences in 5-year death-censored/overall graft survival rates, rates of surgical complications, or incidence of delayed graft function between the groups. During the study period, significantly more candidates for second than first KT were rejected for this procedure because of their high immunologic risk (20% vs 2%, P < 001). Seven of the 42 patients in the second KT group required the removal of the primary graft during the second transplantation.

CONCLUSION

There is a higher percentage of patients whose DSA has been detected among patients undergoing retransplantation after allograft failure than among those receiving first KTs, which often leads to remaining on the waiting list in the former group. However, if the immunologic risk is within acceptable limits, the graft survival for retransplantation is not inferior to that of a first KT.

Association between Hemoglobin A1c and Renal Arteriolar Sclerosis in Subjects Presenting without any Apparent Kidney Dysfunction

AIMS

Diabetic kidney disease is a major vascular complication in patients with diabetes mellitus (DM). However, the association between the hemoglobin (Hb)A1c levels, notably the prediabetic levels, and renal pathological changes remains unclear. We investigated the association between the HbA1c levels and renal arteriolar lesions in subjects without any apparent kidney dysfunction using a living kidney donor cohort.

METHODS

Between January 2006 and May 2016, 393 living kidney donors underwent a "zero-time" biopsy at Kyushu University Hospital. The patients were divided into four groups (HbA1c levels ＜5.6%, 5.6%-5.7%, 5.8%-6.4%, and ≥ 6.5%, or diagnosed with DM [DM group]). Renal arteriolar hyalinization and wall thickening were assessed using semi-quantitative grading. We then investigated the association between the HbA1c levels and renal pathological changes.

RESULTS

158 (40.2%) patients had arteriolar hyalinization and 148 (37.6%) showed wall thickening. A significant correlation was observed between the HbA1c levels and wall thickening (p for trend ＜0.001). An elevated HbA1c level was significantly associated with wall thickening according to a multivariable logistic analysis in subjects with HbA1c levels of 5.6%-5.7% and 5.8%-6.4%, and the DM group, compared with those with HbA1c levels of ＜5.6% (odds ratio [OR], 1.91; 95% confidence interval [CI]: [1.03-3.54] for 5.6%-5.7%, OR, 1.96; 95% CI: [1.09-3.53] for 5.8%-6.4%, and OR, 2.86; 95% CI: [0.91-9.01] for the DM group), whereas arteriolar hyalinization did not increase within the nondiabetic HbA1c levels.

CONCLUSIONS

Elevated high-normal HbA1c levels are considered to be independent risk factors for arteriolar wall thickening. Subclinical renal arteriolar sclerosis may develop in patients with prediabetic HbA1c levels.

Cumulative smoking dose is associated with subclinical renal injury: a pathological study in individuals without chronic kidney disease

BACKGROUND

Epidemiological studies have identified smoking as an independent risk factor for development of chronic kidney disease. However, the early renal pathological lesions have not been clearly elucidated.

METHODS

We investigated time-zero biopsy specimens from 547 living kidney donors and evaluated the relationships between smoking and renal histological changes, including arteriolar hyalinization, intimal thickening of small-medium arteries, global glomerulosclerosis, and interstitial fibrosis and tubular atrophy (IF/TA).

RESULTS

A total of 199 subjects (36.4%) had smoking history; 92 (16.8%) and 107 (19.6%) subjects had <20 pack-years and ≥20 pack-years of smoking, respectively. Cumulative smoking dose was significantly associated with prevalence of arteriolar hyalinization: the multivariable-adjusted odds ratio (OR) per 20 pack-year increase was 1.50 (95% confidence interval 1.15-1.97). The ORs for smokers with <20 pack-years and ≥20 pack-years versus never-smokers were 1.76 (1.01-3.09) and 2.56 (1.48-4.44), respectively. Smoking was also associated with prevalence of >10% global glomerulosclerosis: the OR per 20 pack-year increase was 1.24 (0.96-1.59). The ORs for smokers with <20 pack-years and ≥20 pack-years versus never-smokers were 1.50 (0.98-2.78) and 2.11 (1.18-3.79), respectively. The ORs for these pathological changes increased significantly depending on cumulative smoking dose. Intimal thickening of small-medium arteries and IF/TA were not associated with smoking status. The prevalence of arteriolar hyalinization remained higher in patients with ≥10 years since smoking cessation than in never-smokers [OR 2.23 (1.03-4.83)].

CONCLUSIONS

Subclinical pathological injury caused by smoking is potentially associated with renal arteriolar hyalinization and glomerular ischaemia.

Design and methods of an open-label, randomized controlled trial to evaluate the effect of pemafibrate on proteinuria in CKD patients (PROFIT-CKD)

BACKGROUND

Hypertriglyceridemia is increasingly considered a residual risk of cardiovascular disease in patients with chronic kidney disease (CKD). Pemafibrate-a novel selective peroxisome proliferator-activated receptor alpha modulator and a new treatment for hypertriglyceridemia in CKD patients-is reported to have fewer side effects in CKD patients than other fibrates. Appropriate control of hypertriglyceridemia can be expected to improve renal prognosis. However, data on the renal protective effect of pemafibrate are limited. This study aims to evaluate the effectiveness of pemafibrate on urinary protein excretion in CKD patients.

METHODS

The Pemafibrate, open-label, Randomized cOntrolled study to evaluate the renal protective eFfect In hyperTriglyceridemia patients with Chronic Kidney Disease (PROFIT-CKD) study is an investigator-initiated, multi-center, open-label, parallel-group, randomized controlled trial. Participants are outpatients with hypertriglyceridemia aged 20 years and over, who have received the care of a nephrologist or a diabetologist for more than 3 months. Inclusion criteria include the following: proteinuria (urine protein/creatinine ratio of ≥ 0.15 g/gCr) within three months before allocation, and hypertriglyceridemia (triglycerides ≥ 150 mg/dL and < 1,000 mg/dL) at allocation. In the treatment group, pemafibrate is added to conventional treatment, while conventional treatment is continued with no additional treatment in the control group. Target patient enrollment is 140 patients. The primary endpoint is the change from baseline in the logarithmic urine protein/creatinine ratio at 12 months after study start.

CONCLUSION

This study will provide new findings on the renal protective effect of pemafibrate in CKD patients.

CLINICAL TRIAL REGISTRATION

This clinical trial was registered at the University Hospital Medical Information Network (UMIN) Center (UMIN-CTR: UMIN000042284).

Treatment of chronic active T cell-mediated rejection after kidney transplantation: A retrospective cohort study of 37 transplants

AIM

Data on the treatment of chronic active T cell-mediated rejection (CA-TCMR) are scarce, and therapeutical strategies for CA-TCMR have not been established. We retrospectively evaluated the outcomes and effects of treatment on pathological and clinical findings in patients with CA-TCMR.

METHODS

This study comprised 37 patients who underwent kidney transplantation at our institute who were diagnosed with CA-TCMR between January 2018 and December 2020. Patients were followed until October 2021.

RESULTS

Thirty-two of the 37 patients were treated. During the observation period, two patients died (5%), and five patients developed allograft loss (13%). A univariate Cox proportional hazards model showed that indication biopsy, higher spot urine protein/creatinine ratio (UPCR), and Banff ci/ct scores were risk factors for allograft loss. Of the treated patients, 23 underwent follow-up biopsies. The Wilcoxon signed-rank test showed significant improvement in the Baff scores for "ti", "i-IFTA", "t", and "t-IFTA" after treatment. On pathology, 13 (57%) of the patients who underwent follow-up biopsy improved to "no evidence of rejection" or "borderline change". Assuming that improvement in pathology to "borderline change" or "no evidence of rejection" on follow-up biopsy indicates response to treatment, multivariate logistic analysis showed that lower UPCR was a predictive factor for response to treatment. No specific effect of treatment type was observed.

CONCLUSIONS

Our results indicate that treatment could improve the pathological findings in CA-TCMR. This article is protected by copyright. All rights reserved.

Subclinical hypothyroidism is independently associated with poor renal outcomes in patients with chronic kidney disease

PURPOSE

It remains unclear whether subclinical hypothyroidism (SCH) is associated with renal prognosis in patients with chronic kidney disease (CKD). Therefore, we prospectively investigated the association of SCH with renal outcomes in CKD.

METHODS

We conducted a prospective observational study of 480 euthyroid patients and 89 patients with SCH. The endpoints were defined as a composite of doubling of serum creatinine (SCr), end-stage renal disease (ESRD), or death, and a composite of doubling of SCr or ESRD was added as an alternative outcome. Logistic regression analyses were used to identify the factors associated with SCH. In addition, a Cox proportional hazards model was performed to determine whether SCH was associated with poor renal outcomes.

RESULTS

During a median follow-up period of 26.1 months, doubling of SCr, ESRD, or death and doubling of SCr or ESRD occurred in 244 and 213 patients, respectively. In univariable logistic regression analyses, SCH was significantly associated with older age, lower hemoglobin, higher proteinuria, lower estimated glomerular filtration rate (eGFR), and higher log B-type natriuretic peptide (BNP). Multivariable Cox analyses showed that SCH was associated with poorer renal outcomes after adjustment for covariates, including eGFR and log BNP [doubling of SCr, ESRD, or death: hazard ratio (HR) 1.61, 95% confidence interval (CI), 1.16-2.23; doubling of SCr or ESRD: HR 1.53, 95% CI 1.07-2.20], compared with euthyroidism.

CONCLUSIONS

In CKD, SCH is independently associated with poor renal outcomes, suggesting that screening for SCH might be needed to accurately predict renal prognosis.

Development and validation of a risk score for the prediction of cardiovascular disease in living donor kidney transplant recipients

BACKGROUND

Cardiovascular disease (CVD) is a major cause of death in kidney transplant (KT) recipients. To improve their long-term survival, it is clinically important to estimate the risk of CVD after living donor KT via adequate pre-transplant CVD screening.

METHODS

A derivation cohort containing 331 KT recipients underwent living donor KT at Kyushu University Hospital from January 2006 to December 2012. A prediction model was retrospectively developed and risk scores were investigated via a Cox proportional hazards regression model. The discrimination and calibration capacities of the prediction model were estimated via the c-statistic and the Hosmer-Lemeshow goodness of fit test. External validation was estimated via the same statistical methods by applying the model to a validation cohort of 300 KT recipients who underwent living donor KT at Tokyo Women's Medical University Hospital.

RESULTS

In the derivation cohort, 28 patients (8.5%) had CVD events during the observation period. Recipient age, CVD history, diabetic nephropathy, dialysis vintage, serum albumin and proteinuria at 12 months after KT were significant predictors of CVD. A prediction model consisting of integer risk scores demonstrated good discrimination (c-statistic 0.88) and goodness of fit (Hosmer-Lemeshow test P = 0.18). In a validation cohort, the model demonstrated moderate discrimination (c-statistic 0.77) and goodness of fit (Hosmer-Lemeshow test P = 0.15), suggesting external validity.

CONCLUSIONS

The above-described simple model for predicting CVD after living donor KT was accurate and useful in clinical situations.

Association between geriatric nutritional risk index and stroke risk in hemodialysis patients: 10-Years outcome of the Q-Cohort study

BACKGROUNDS AND AIMS

The geriatric nutritional risk index (GNRI), which is calculated using the serum albumin level and body mass index, is a nutritional marker associated with an increased risk of cardiovascular events in patients who are receiving hemodialysis. However, no studies have examined the association between the GNRI level and the incidence of stroke in this population.

METHODS

Three thousand forty-five patients were registered in the Q-Cohort Study, which is a multicenter, observational cohort of hemodialysis patients. The main outcomes were brain infarction and brain hemorrhage. The main exposure was GNRI levels at baseline. Patients were divided into quartiles on the basis of baseline GNRI levels: Q1, <90.7; Q2, 90.7-95.5; Q3, 95.6-99.8; Q4, >99.8. The risk of brain infarction or hemorrhage was estimated using the multivariable-adjusted Cox proportional hazard risk models and restricted cubic spline analyses.

RESULTS

During the 10-year follow-up period, 326 patients developed brain infarction and 149 patients developed brain hemorrhage. Cox proportional hazard risk models showed that the risk of brain infarction and hemorrhage in Q1 was significantly higher than that in Q4 group. The hazard ratios [95% confidence intervals] were 1.49 [1.05-2.12] and 1.89 [1.11-3.20], respectively. Restricted cubic spline curves showed that a lower GNRI was incrementally associated with an increased risk for both brain infarction and brain hemorrhage.

CONCLUSIONS

Our results suggest that a lower GNRI is an independent risk factor for both brain infarction and hemorrhage in patients who are receiving maintenance hemodialysis.

Significance of revised criteria for chronic active T cell-mediated rejection in the 2017 Banff classification: Surveillance by 1-year protocol biopsies for kidney transplantation

Diagnostic criteria for chronic active T cell-mediated rejection (CA-TCMR) were revised in the Banff 2017 consensus, but it is unknown whether the new criteria predict graft prognosis of kidney transplantation. We enrolled 406 kidney allograft recipients who underwent a 1-year protocol biopsy (PB) and investigated the diagnostic significance of Banff 2017. Interobserver reproducibility of the 3 diagnosticians showed a substantial agreement rate of 0.68 in Fleiss's kappa coefficient. Thirty-three patients (8%) were classified as CA-TCMR according to Banff 2017, and 6 were previously diagnosed as normal, 12 as acute TCMR, 10 with borderline changes, and 5 as CA-TCMR according to Banff 2015 criteria. Determinant factors of CA-TCMR were cyclosporine use (vs tacrolimus), previous acute rejection, and BK polyomavirus-associated nephropathy. In survival analysis, the new diagnosis of CA-TCMR predicted a composite graft endpoint defined as doubling serum creatinine or death-censored graft loss (log-rank test, P < .001). In multivariate analysis, CA-TCMR was associated with the second highest risk of the composite endpoint (hazard ratio: 5.42; 95% confidence interval, 2.02-14.61; P < .001 vs normal) behind antibody-mediated rejection. In conclusion, diagnosis of CA-TCMR in Banff 2017 may facilitate detecting an unfavorable prognosis of kidney allograft recipients who undergo a 1-year PB.

Utility of Columbia classification in focal segmental glomerulosclerosis: renal prognosis and treatment response among the pathological variants

BACKGROUND

The utility of the Columbia classification (Col-class) for focal segmental glomerulosclerosis (FSGS) has not yet been fully proven.

METHODS

We extracted 201 FSGS patients from 10 nephrology centers in Japan and investigated the difference of a composite renal endpoint, defined as doubling of serum creatinine and/or development of end-stage renal disease, in pathological variants. Sensitivity analysis was used to prove the utility of the Col-class to predict renal outcomes. Additionally, the renal protective effects of steroids and/or immunosuppression (steroid/IS) were investigated in patients stratified according to the Col-class.

RESULTS

The patients were classified into the following variants: not otherwise specified [NOS; n = 121 (60.1%)], perihilar [n = 31 (15.4%)], cellular [n = 19 (9.5%)], tip [n = 17 (8.5%)] and collapsing [n = 13 (6.5%)]. No tip variant patients reached the renal endpoint. The renal outcome in the collapsing variant was significantly poorer than that in the NOS [hazard ratio (HR) 3.71; P = 0.005]. In the sensitivity analysis, the area under the receiver operating characteristic curve for the renal endpoint was increased by adding Col-class to a model including common risk factors (P = 0.021). In a subgroup treated without steroid/IS, the outcome in the cellular variant was worse than that in the NOS (HR 5.10; P = 0.040) but the difference was not observed in the subgroup with steroid/IS (HR 0.54; P = 0.539).

CONCLUSIONS

The Col-class is useful to predict renal prognosis in Japanese patients with FSGS. In addition to good prognosis in the tip variant and poor in the collapsing variant, good clinical course in the cellular variant treated with steroid/IS was suggested.

Comparison of Immunohistochemical Staining for Large T Antigen and Capsid Protein VP1 in BK Polyomavirus-Associated Nephropathy

AIM

Most transplant centres use SV40 large T antigen (TAg) staining for the diagnosis and assessment of BK polyomavirus-associated nephropathy (BKPyVAN). This study was performed to evaluate the significance of capsid protein VP1 expression in BKPyVAN.

METHODS

We performed immunohistochemical staining using anti-SV40 TAg and anti-BKPyV VP1 antibodies in 16 index biopsies and 12 re-biopsies of BKPyVAN and compared the patterns of positivity and the percentage of positive tubules by counting whole specimens. We investigated the correlation between serum creatinine increase from baseline and the percentage of positive tubules for both markers in 16 index biopsies.

RESULTS

In VP1 staining, positive findings were observed not only in the nuclei of tubular epithelial cells but also in the cytoplasm, cells shedding into the lumen, intra-tubular casts, and in the interstitium. Two of 28 biopsies (7.1%) showed TAg-positive and VP1-negative results, in which TAg-positive cells were detected only in a single tubule. The median (interquartile range) percentage of positive tubules was 2.8% (0.7-9.8%) for TAg and 1.4% (0.5-3.9%) for VP1 staining (p = 0.2). In 16 index biopsies, serum creatinine increases significantly correlated with the percentage of VP1-positive tubules (r = 0.49, p = 0.02), while this correlation revealed borderline significance with TAg-positive tubules.

CONCLUSIONS

VP1 expression showed various patterns, but was detected in half as many tubules as TAg staining, which might lead to false negatives in the samples with minimal viral replication. However, increased VP1-positive tubules indicate advanced tubular damage and possible association with graft dysfunction.

Neurological Disorders Identified during Treatment of a SARS-CoV-2 Infection

A 69-year-old man was admitted to our hospital under diagnosis of pneumonia due to severe acute respiratory syndrome-corona virus 2 (SARS-CoV-2) (Day 0). He underwent endotracheal intubation from Day 3. Although his respiratory condition improved and anesthetic drugs were discontinued, no cough reflex was observed despite intubation having been performed until Day 17. His tendon reflexes were also diminished. We suspected that he had developed Guillain-Barré syndrome (GBS), and administered intravenous immunoglobulin from Day 18. The absence of cough reflex improved and extubation was successfully performed on Day 23. Neurological disorders including GBS should be considered when intubated SARS-CoV-2 patients present with a loss of cough reflex during the treatment period.

High low-density lipoprotein cholesterol as an independent risk factor for coronary restenosis in hemodialysis patients undergoing percutaneous coronary interventions

HD patients have been reported to have a higher risk of restenosis after percutaneous coronary intervention (PCI). The aim of this study was to investigate the risk factors of coronary restenosis in HD patients. We enrolled 54 HD patients (mean age: 66.5 ± 10.1 years; 72.2% men; mean HD duration: 3.7 years), who received PCI and follow-up coronary angiography. Of the patients, 22 (40.7%) had restenosis within 3 to 12 months of PCI. Univariate logistic analysis showed low-density lipoprotein cholesterol (LDL-C)/high-density lipoprotein cholesterol (HDL-C) ratio, LDL-C, non-HDL-C, and history of major adverse cardiovascular events were significantly associated with coronary restenosis (OR]: 1.89, 1.27, 1.22, and 5.79, respectively). Multivariate analysis showed that LDL-C was significantly associated with coronary restenosis (OR: 1.43). These data suggest that LDL-C is an independent risk factor for coronary restenosis in HD patients undergoing PCI, and strict lipid management may be required.

Survival comparison between superficialization of the brachial artery and tunneled central venous catheter placement in hemodialysis patients with heart failure: A retrospective study

It remains unclear which vascular access provides better survival in hemodialysis patients with heart failure, superficialization of the brachial artery (SBA), or tunneled central venous catheter (TCVC). We retrospectively followed up 60 hemodialysis patients with heart failure who underwent SBA (n = 36) or TCVC placement (n = 24). During the median 2.2-year follow-up period, 36 patients died. The median survival time was significantly longer for the SBA group than for the TCVC group (5.7 vs 1.7 years; P < .05, log-rank test). A multivariate-adjusted Cox regression analysis showed that SBA was associated with a reduced risk of all-cause death (hazard ratio [HR] 0.30; 95% confidence interval [CI] 0.14-0.65). In the cohort of propensity score-matched 15 pairs, patients with SBA experienced fewer all-cause deaths (HR 0.29; 95% CI 0.10-0.77). Our study suggests that SBA is an alternative option in hemodialysis patients with heart failure.

Development and validation of a new prediction model for graft function using preoperative marginal factors in living-donor kidney transplantation

BACKGROUND

Recently, living-donor kidney transplantation from marginal donors has been increasing. However, a simple prediction model for graft function including preoperative marginal factors is limited. Here, we developed and validated a new prediction model for graft function using preoperative marginal factors in living-donor kidney transplantation.

METHODS

We retrospectively investigated 343 patients who underwent living-donor kidney transplantation at Kyushu University Hospital (derivation cohort). Low graft function was defined as an estimated glomerular filtration rate of < 45 mL/min/1.73 m² at 1 year. A prediction model was developed using a multivariable logistic regression model, and verified using data from 232 patients who underwent living-donor kidney transplantation at Tokyo Women's Medical University Hospital (validation cohort).

RESULTS

In the derivation cohort, 89 patients (25.9%) had low graft function at 1 year. Donor age, donor-estimated glomerular filtration rate, donor hypertension, and donor/recipient body weight ratio were selected as predictive factors. This model demonstrated modest discrimination (c-statistic = 0.77) and calibration (Hosmer-Lemeshow test, P = 0.83). Furthermore, this model demonstrated good discrimination (c-statistic = 0.76) and calibration (Hosmer-Lemeshow test, P = 0.54) in the validation cohort. Furthermore, donor age, donor-estimated glomerular filtration rate, and donor hypertension were strongly associated with glomerulosclerosis and atherosclerotic vascular changes in the "zero-time" biopsy.

CONCLUSIONS

This model using four pre-operative variables will be a simple, but useful guide to estimate graft function at 1 year after kidney transplantation, especially in marginal donors, in the clinical setting.

Association of Lower Serum Bilirubin With Loss of Residual Kidney Function in Peritoneal Dialysis Patients

Bilirubin is recognized as an endogenous antioxidant, and low serum bilirubin is reported to be associated with the progression of kidney disease. However, it is unclear whether serum bilirubin levels are associated with the loss of residual kidney function (RKF) in peritoneal dialysis (PD) patients. This study investigated the relationship between serum total bilirubin and loss of RKF. We prospectively followed 94 PD patients who started PD in our hospital between June 2006 and May 2016. Ten patients who had chronic liver disease or cirrhosis were excluded. Patients were divided into three groups based on serum total bilirubin concentration tertiles: tertile 1 (T1) < 0.3, T2 = 0.3, and T3 ≥ 0.4 mg/dL. We estimated the relationship between serum bilirubin and loss of RKF, defined as daily urine volume (<100 mL) within 3 years after starting PD, using a Cox proportional hazards model. During the 3-year observation period, 22 patients lost RKF. The incidence rate of loss of RKF increased linearly with the decrease in serum total bilirubin levels (P for trend < 0.05). After adjusting for confounding factors, low serum total bilirubin level was shown to be an independent predictor of loss of RKF (hazard ratio [HR] for every 0.1 mg/dL decrease, 1.50; 95% confidence interval [CI], 1.01-2.51; HR [95%CI] for T2 and T1 [vs. T3] 2.03 [0.65-7.88] and 3.70 [1.00-15.9]). This study suggests that low serum total bilirubin levels are associated with the loss of RKF in PD patients.

Rapidly Progressive Glomerulonephritis with Delayed Appearance of Anti-Glomerular Basement Membrane Antibody Successfully Treated with Multiple Courses of Steroid Pulse Therapy

Patients with anti-glomerular basement membrane (GBM) antibody glomerulonephritis typically exhibit rapidly progressive glomerulonephritis (RPGN). The renal outcome as well as the prognosis of this disease is worse than other forms of RPGN such as those from microscopic polyangiitis. Therefore, early therapeutic intervention is essential to improve its prognosis. One month before referral to our hospital, a 54-year-old female attended another hospital because of macrohematuria. At that time, she had proteinuria and macrohematuria with normal renal function, was negative for anti-GBM antibodies, and was diagnosed with chronic glomerulonephritis. A month later when she was admitted to our hospital, she showed renal insufficiency and was positive for anti-GBM antibodies. Immediately after recognizing the anti-GBM antibody status, plasma exchange and the first course of steroid pulse therapy was started. After 5 days of therapy, renal biopsy confirmed severe crescentic glomerulonephritis in which all the observed glomeruli were involved with cellular crescents. Despite this, she survived without end-stage renal disease after three courses of steroid pulse therapy and seven sessions of plasma exchange. This favorable outcome reflects the repeated analysis of anti-GBM antibodies within a very short period and the rapid therapeutic intervention in addition to the intensive immunosuppressive therapies.

Development of a risk prediction model for infection-related mortality in patients undergoing peritoneal dialysis

Background

Assessment of infection-related mortality remains inadequate in patients undergoing peritoneal dialysis. This study was performed to develop a risk model for predicting the 2-year infection-related mortality risk in patients undergoing peritoneal dialysis.

Methods

The study cohort comprised 606 patients who started and continued peritoneal dialysis for 90 at least days and was drawn from the Fukuoka Peritoneal Dialysis Database Registry Study in Japan. The patients were registered from 1 January 2006 to 31 December 2016 and followed up until 31 December 2017. To generate a prediction rule, the score for each variable was weighted by the regression coefficients calculated using a Cox proportional hazard model adjusted by risk factors for infection-related mortality, including patient characteristics, comorbidities, and laboratory data.

Results

During the follow-up period (median, 2.2 years), 138 patients died; 58 of them of infectious disease. The final model for infection-related mortality comprises six factors: age, sex, serum albumin, serum creatinine, total cholesterol, and weekly renal Kt/V. The incidence of infection-related mortality increased linearly with increasing total risk score (P for trend <0.001). Furthermore, the prediction model showed adequate discrimination (c-statistic = 0.79 [0.72–0.86]) and calibration (Hosmer–Lemeshow test, P = 0.47).

Conclusion

In this study, we developed a new model using clinical measures for predicting infection-related mortality in patients undergoing peritoneal dialysis.

Effect of steroid pulse therapy on post-transplant immunoglobulin A nephropathy

AIM

Recent studies have suggested that patients with post-transplant immunoglobulin A nephropathy have poor graft survival. There is limited research on the therapeutic effectiveness for post-transplant immunoglobulin A nephropathy, especially steroid pulse therapy. The present study evaluated the efficacy of steroid pulse therapy on post-transplant immunoglobulin A nephropathy.

METHODS

We retrospectively analyzed patients diagnosed with de novo or recurrent immunoglobulin A nephropathy at Kyushu University Hospital between January 2013 and August 2015. Patients with moderate proteinuria (≥0.5 g/g creatinine) and/or cellular or fibrocellular crescents on a graft biopsy were treated with steroid pulse therapy. Steroid pulse therapy was 500 mg/day for 3 days in weeks 1 and 2, followed by 20 mg of oral prednisolone that was tapered after 6 months. Patients were followed for 2 years, and the estimated glomerular filtration rate, urinary findings, and adverse events were recorded.

RESULTS

Seven patients received steroid pulse therapy. The mean duration after kidney transplantation was 6.6 ± 4.7 years. After 2 years of treatment, 85.7% of patients reached complete remission of proteinuria, urinary protein excretion declined (0.82 ± 0.51 to 0.26 ± 0.22 g/g creatinine, P = 0.007), and the estimated glomerular filtration rate was maintained (48.7 ± 12.8 to 47.4 ± 14.0 mL/min per 1.73 m² , P = 0.98). Adverse events were observed in one patient who developed herpes zoster infection.

CONCLUSION

Steroid pulse therapy for post-transplant immunoglobulin A nephropathy effectively reduces proteinuria over 2 years. However, comparison of steroid pulse therapy and other regimens with a high-quality design is required.

Thrombotic microangiopathy associated with anticardiolipin antibody in a kidney transplant recipient with polycythemia

Thrombotic microangiopathy (TMA) develops from various etiologies, and it is often difficult to distinguish the etiology of TMA in kidney transplantation. Antiphospholipid syndrome (APS) is one of the differential diagnoses for TMA that may cause acute loss of graft function or fatal thrombotic complications. This report details a 66-year-old male patient with polycythemia after ABO-incompatible kidney transplantation. Antibody screening tests were negative before transplant. Despite administration of an adequate desensitization therapy including plasmapheresis and rituximab, he developed acute graft dysfunction on postoperative day 112 and graft biopsy revealed prominent microvascular inflammation in the glomerular capillaries without immunoglobulin deposits. Flow cytometric panel-reactive antibody screening failed to detect donor-specific antibodies at both pre-transplant and episode biopsies. Anticardiolipin antibody was repeatedly positive, but neither thrombosis nor previous thrombotic episodes were detected. After excluding several differential diagnoses, the graft dysfunction with unexplained TMA was treated with steroid pulse, plasmapheresis and rituximab re-induction. Anticardiolipin antibody disappeared after this intensive treatment and graft function recovered gradually and stabilized for 52 months. This report suggests that asymptomatic anticardiolipin antibody may be associated with acute graft dysfunction. Even if thrombotic episodes are not observed, an exist of anticardiolipin antibody may be one of the risk factors of renal TMA after kidney transplantation.

Association of geriatric nutritional risk index with infection-related mortality in patients undergoing hemodialysis: The Q-Cohort Study

BACKGROUND & AIMS

The geriatric nutritional risk index (GNRI) is a simple but useful nutritional marker for all-cause mortality and cardiovascular mortality in patients undergoing hemodialysis (HD). However, whether the GNRI can predict infection-related mortality in patients undergoing HD remains unclear, and there is insufficient evidence regarding whether the GNRI improves the predictive value for risk assessment beyond the existing conventional nutritional markers. Here, we investigated the association between the GNRI and infection-related mortality in patients undergoing HD and evaluated the predictive value of GNRI.

METHODS

A prospective cohort study was performed on a total of 3436 Japanese HD patients aged ≥18 years. Patients were divided into four groups by quartiles of GNRI: (Quartile 1 [Q1], >100.2; Q2, 95.9-100.2; Q3, 90.8-95.8; Q4, <90.8). We estimated the relationship between GNRI and all-cause mortality and infection-related mortality using a Cox proportional hazards model. To assess the additional predictive value of the GNRI in risk assessment, we compared the c-statistic, net reclassification improvement, and integrated discrimination improvement among serum albumin, serum creatinine, and the GNRI.

RESULTS

During follow-up period (median, 4.0 years), a total of 564 patients died; 120 of these patients died of infectious disease. All-cause mortality and infection-related mortality increased linearly with lower GNRI levels. After adjusting for confounding risk factors, the GNRI was an independent predictor of infection-related mortality as well as all-cause mortality (hazard ratio [HR], 5.89; 95% confidence interval [CI], 2.85-13.8; P < 0.001 for Q4 vs. Q1, HR, 2.62; 95% CI, 1.23-6.24; P = 0.01 for Q3 vs. Q1). Additionally, when the GNRI was incorporated into a model with potential risk factors instead of serum albumin, the c-statistic increased significantly (0.811 vs. 0.821, P = 0.03), and the net reclassification improvement and integrated discrimination improvement was 0.26 (P = 0.005) and 0.005 (P = 0.01). This association was more apparent in the older patients (0.739 vs. 0.760, P = 0.02) than in the younger patients (0.916 vs. 0.912, P = 0.35). Similar results were observed between serum creatinine and the GNRI, but the difference did not reach statistical significance.

CONCLUSIONS

Lower GNRI levels are an independent risk factor for infection-related mortality in patients undergoing HD. Moreover, addition of the GNRI to models with standard risk factors significantly improves the predictive ability of infection-related mortality, especially in older patients.

Study on Dialysis Session Length and Mortality in Maintenance Hemodialysis Patients: The Q-Cohort Study

<b><i>Objectives:</i></b> Hemodialysis (HD) time has been recognized as an important factor in dialysis adequacy. However, few studies have reported on associations between HD time and prognosis among maintenance HD patients. We present some findings from a prospective cohort study, the ­Q-Cohort Study, which was set up to explore risk factors for mortality in Japanese HD patients. We hypothesized that HD ≥5 h was associated with a significant survival advantage compared with HD &#x3c; 5 h. The present study examined association between HD time and mortality in Japanese HD patients. <b><i>Methods:</i></b> The prospective multicenter Q-Cohort Study was conducted between December 2006 and December 2010, following 3,456 Japanese HD patients for 4 years. We examined the association between HD time and prognosis using Cox proportional hazards modeling. Propensity scores were calculated using logistic regression. <b><i>Results:</i></b> During follow-up, 566 patients died from any cause. Patients with HD ≥5 h (<i>n</i> = 2,141) showed ­significantly lower risk of all-cause death (hazards ratio = 0.82; 95% CI 0.68–0.99) than those with HD &#x3c; 5 h (<i>n</i> = 1,315), after adjusting for confounding risk factors. This ­association remained significant using a propensity score-based approach. After stratifying the analysis by patient age in 10-year increments, this finding remained ­significant only in patients who were ≥80 years of age. <b><i>Conclusion:</i></b> Our results suggest that HD ≥5 h has a more favorable effect on mortality than HD &#x3c; 5 h.

Association between serum uric acid level and renal arteriolar hyalinization in individuals without chronic kidney disease

BACKGROUND AND AIMS

Recent studies have reported an association between serum uric acid (SUA) and renal arteriolar changes in patients with chronic kidney disease (CKD). However, the association in individuals without CKD remains unclear. In this study, we investigated the relationship between SUA and renal arteriolar lesions in individuals without CKD from our living kidney donor cohort.

METHODS

Between January 2006 and May 2016, 393 living kidney donors underwent "time-zero" biopsy at Kyushu University Hospital. Patients were divided into sex-specific quartiles of SUA before donation: Q1, Q2, Q3, and Q4 (male: <5.2,5.2-5.8,5.9-6.4, and ≥6.5 mg/dL, female: <3.8,3.8-4.3,4.4-5.0, and ≥5.1 mg/dL). Renal arteriolar hyalinization and wall thickening were assessed using a semiquantitative grading system. Predictive performance was compared between models with and without SUA by calculating the net reclassification improvement (NRI).

RESULTS

In total, 158 (40.2%) patients had arteriolar hyalinization, and 148 (37.6%) had wall thickening. High SUA was significantly associated with arteriolar hyalinization in multivariable logistic analysis (odds ratio [OR] per 1-mg/dL increase in SUA, 1.24; 95% confidence interval [CI], 1.00-1.53; p = 0.048. OR for Q4 vs. Q2, 2.22; 95% CI, 1.17-4.21; p = 0.01). We found no association between SUA and wall thickening. When SUA was incorporated into a predictive model with conventional atherosclerotic factors, the NRI was 0.21 (p = 0.04).

CONCLUSIONS

High SUA was an independent risk factor for arteriolar hyalinization in individuals without CKD. SUA provided additional predictive value beyond conventional atherosclerotic factors in predicting arteriolar hyalinization.

The potential role of perivascular lymphatic vessels in preservation of kidney allograft function

BACKGROUND

Lymphangiogenesis occurs in diseased native kidneys and kidney allografts, and correlates with histological injury; however, the clinical significance of lymphatic vessels in kidney allografts is unclear.

METHODS

This study retrospectively reviewed 63 kidney transplant patients who underwent protocol biopsies. Lymphatic vessels were identified by immunohistochemical staining for podoplanin, and were classified according to their location as perivascular or interstitial lymphatic vessels. The associations between perivascular lymphatic density and kidney allograft function and pathological findings were analyzed.

RESULTS

There were no significant differences in perivascular lymphatic densities in kidney allograft biopsy specimens obtained at 0 h, 3 months and 12 months. The groups with higher perivascular lymphatic density showed a lower proportion of progression of interstitial fibrosis/tubular atrophy grade from 3 to 12 months (P for trend = 0.039). Perivascular lymphatic density was significantly associated with annual decline of estimated glomerular filtration rate after 12 months (r = -0.31, P = 0.017), even after adjusting for multiple confounders (standardized β = -0.30, P = 0.019).

CONCLUSIONS

High perivascular lymphatic density is associated with favourable kidney allograft function. The perivascular lymphatic network may be involved in inhibition of allograft fibrosis and stabilization of graft function.

Light Chain Deposition Disease in an Older Adult Patient Successfully Treated with Long-term Administration of Bortezomib, Melphalan and Prednisone

A 70-year-old woman was admitted to our hospital because of fatigue and renal dysfunction and was diagnosed with light chain deposition disease (LCDD) with multiple organ involvement (kidney, thyroid gland, heart and eyes). After chemotherapy with bortezomib, cyclophosphamide and dexamethasone, hepatobiliary enzyme levels increased abruptly. A liver biopsy showed light chain deposition in Disse spaces. After two years of treatment with bortezomib, melphalan and prednisone (VMP) administered at shorter intervals relative to regular cycles, the patient showed a hematological and organ response. This case indicates that a relatively low dose intensity VMP regimen is preferable for elderly patients with LCDD with multiple organ involvement.

Membranoproliferative glomerulonephritis with predominant IgG2 and IgG3 deposition in a patient with IgG4-related disease

Background

IgG4-related disease is a novel disease entity characterized by elevated serum IgG4 and tissue infiltration by IgG4-positive plasma cells. Typical renal pathology is tubulointerstitial nephritis with storiform fibrosis, although the co-existence of various glomerular lesions has been described. Here, we present the first report of a case of IgG4-related kidney disease and membranoproliferative glomerulonephritis showing the discrepancy in IgG subclasses between the kidney interstitium and glomeruli.

Case presentation

A 70-year-old Japanese woman was diagnosed with membranoproliferative glomerulonephritis and focal tubulointerstitial nephritis with IgG4-positive plasma cells. Immunofluorescence studies revealed predominant deposition of IgG3 and IgG2, but not IgG4 in the glomeruli. We administered oral prednisolone at 30 mg/day, and the abnormalities in urine and blood tests gradually resolved.

Conclusion

In this case, different patterns of IgG subclasses detected in the glomeruli and interstitial plasma cells suggest overlapping immunologic abnormalities. The favorable clinical course in our patient suggests that steroid therapy is promising in cases of IgG4-related kidney disease accompanied by glomerulonephritis.

A case of bacterial peritonitis caused by Roseomonas mucosa in a patient undergoing continuous ambulatory peritoneal dialysis

Bacterial peritonitis remains a life-threatening complication of peritoneal dialysis (PD). Roseomonas is a bacterial genus of pink-pigmented, oxidized, gram-negative coccobacilli that was first named in 1993. Importantly, Roseomonas mucosa exhibits antibiotic resistance, with significant resistance to cephalosporin, which is often selected as an empirical antibiotic regimen for peritonitis in PD patients. We herein report the case of a PD patient with bacterial peritonitis caused by Roseomonas mucosa that was fortunately identified using 16S rRNA gene sequencing and successfully treated with ciprofloxacin. Given that Roseomonas demonstrates resistance to a variety of antibiotics. The administration of empiric antibiotic therapy based on the recommendation of the International Society of Peritoneal Dialysis guidelines occasionally fails, leading to the aggravation of bacterial peritonitis. Hence, nephrologists should consider Roseomonas as one of the potential causative organisms of peritonitis, especially when gram-negative bacilli are resistant to cephalosporin and cannot be identified using standard laboratory methods.

Hepatitis C virus RNA present in saliva but absent in breast-milk of the hepatitis C carrier mother

In order to examine whether saliva and breast-milk are mediators of the vertical transmission of hepatitis C virus (HCV) from an HCV carrier mother, serum, saliva, and breast-milk samples from 11 HCV carrier mothers were collected at the time of delivery, and at approximately 1- to 3-months intervals for as long as 30 months postpartum. Serum was also sampled from their children. All samples were analysed for the presence of HCV RNA, using the nested polymerase chain reaction method. No HCV RNA was detected in any breast-milk samples. In saliva, HCV RNA was detected in four of the 11 mothers (36%). These four mothers also had liver function abnormalities. Hepatitis C virus RNA was not detected in any serum samples of the children, and all children had normal liver function. The children were monitored for periods from 2 to 44 months. During this period, there was no evidence of virus transmission. Breast-milk is not likely to be a source of mother-to-child transmission of HCV. Maternal saliva may harbour HCV, but it may not result in infant infection.

A case of siblings with Meckel's diverticulum diagnosed before operation

The authors encountered a sibling case of Meckel's diverticulum in 9 and 11 year old Japanese boys. They were diagnosed using contrast examination and 99mTc-pertechnetate scintigraphy before operation. The familial tendency is one in every 2500 families. Only 15 cases of familial occurrence have been reported by five authors.

[Clinical studies on cefprozil granules in pediatric skin soft tissues infections]

Cefprozil (CFPZ), a newly developed cephalosporin in fine granular form, was administered to pediatric patients with skin and soft tissue infections. MICs were determined for 6 drugs including CFPZ, cephalexin (CEX), cefaclor (CCL), ampicillin (ABPC), methicillin (DMPPC), cloxacillin (MCIPC) against 53 clinical isolates of Staphylococcus aureus from these patients. An inoculum size of 10(6) CFU/ml was used in the MIC-determinations. CFPZ was given to 73 patients with ages ranging from 6 months to 10 years and 8 months and 71 cases were evaluable for clinical effects as follows; impetigo (65), Staphylococcal scalded skin syndrome (1), furuncle (1), subcutaneous abscess (3), and periproctal abscess (1). To study clinical efficacy, bacteriological effects and safety of this drug, a mean dose of 8.4 mg/kg with 3-4 daily dosages (57 cases of t.i.d. and 14 cases of q.i.d.) was administered for an average of 6 days. The results obtained are summarized as follows. 1. With regard to the 53 isolates of S. aureus, MICs of CFPZ against 52 strains (98.1%) ranged from 0.78 to 3.13 micrograms/ml. 45 strains (84.9%) were inhibited at 0.78 micrograms/ml. MIC90 of CFPZ was 1.56 micrograms/ml, but MIC against 1 strain of Methicillin-resistant S. aureus (MRSA) was 100 micrograms/ml. The MIC90 of CEX and CCL were 6.25 micrograms/ml and MIC of CEX and CCL against 1 MRSA strain were 200 and 100 micrograms/ml, respectively. The MIC90 of ABPC, DMPPC and MCIPC were 6.25, 3.13 and 0.39 micrograms/ml, respectively. CFPZ showed the second highest activity after MCIPC against S. aureus. 2. CFPZ showed very good clinical responses and clinical effects in 71 patients all of whom judged by doctors in charge as having "good" or better responses. 3. For impetigo patients, the evaluable cases by score 3, 5 and 7 days after administration of the drug were 52, 39 and 20 patients, respectively. The efficacy rates on these days were 90.4, 100 and 100%, respectively. The efficacy rate at a daily dose of 30.1-45.0 mg/kg on day 3 was 17.2% higher than that at 22.5-30.0 mg/kg, and the "excellent" response rate of 30.1-45.0 mg/kg group was 45.3% greater. Because of these results, it is expected that good clinical effects can be obtained at a daily dose of 22.5-30.0 mg/kg of CFPZ, but better responses can be expected at 30.1-45.0 mg/kg in 3-4 divided doses given for 5 days. 4. Bacteriological effects of CFPZ were determined against 60 strains of S. aureus.(ABSTRACT TRUNCATED AT 400 WORDS)