Background: Pneumonia accounts for the majority of infection-related deaths after kidney transplantation. We aimed to build a predictive model based on machine learning for severe pneumonia in recipients of deceased-donor transplants within the perioperative period after surgery. Methods: We collected the features of kidney transplant recipients and used a tree-based ensemble classification algorithm (Random Forest or AdaBoost) and a nonensemble classifier (support vector machine, Naïve Bayes, or logistic regression) to build the predictive models. We used the area under the precision-recall curve (AUPRC) and the area under the receiver operating characteristic curve (AUROC) to evaluate the predictive performance via ten-fold cross validation. Results: Five hundred nineteen patients who underwent transplantation from January 2015 to December 2018 were included. Forty-three severe pneumonia episodes (8.3%) occurred during hospitalization after surgery. Significant differences in the recipients’ age, diabetes status, HBsAg level, operation time, reoperation, usage of anti-fungal drugs, preoperative albumin and immunoglobulin levels, preoperative pulmonary lesions, and delayed graft function, as well as donor age, were observed between patients with and without severe pneumonia (P<0.05). We screened eight important features correlated with severe pneumonia using the recursive feature elimination method and then constructed a predictive model based on these features. The top three features were preoperative pulmonary lesions, reoperation and recipient age (with importance scores of 0.194, 0.124 and 0.078, respectively). Among the machine learning algorithms described above, the Random Forest algorithm displayed better predictive performance, with a sensitivity of 0.67, specificity of 0.97, positive likelihood ratio of 22.33, negative likelihood ratio of 0.34, AUROC of 0.91, and AUPRC of 0.72. Conclusions: The Random Forest model is potentially useful for predicting severe pneumonia in kidney transplant recipients. Recipients with a potential preoperative potential pulmonary infection, who are of older age and who require reoperation should be monitored carefully to prevent the occurrence of severe pneumonia.

Recipients of living donor renal transplantation are typically considered to have a relatively lower immunological risk. This retrospective study aimed to compare the therapeutic efficacy and safety between rabbit antithymocyte globulin (rATG) or interleukin-2 receptor antagonist (IL2-RA) induction therapies in Chinese population. A total of 188 patients receiving living donor renal transplantation between February 2004 and December 2013 were included and divided into the rATG group and based on their induction therapy. The primary outcome was clinically-suspected rejection. The incidences of de novo donor-specific antigen (dn-DSA), graft survival, and infection were also compared between groups. A multivariate Cox regression analysis was performed to investigate the influential factors associated with clinically-suspected acute rejection and graft survival. The rATG group had a higher panel reactive antibody (PRA) score and more complete HLA mismatches than the IL2-RA group (both P < 0.001). The incidences of clinically-suspected acute rejection (9.8% vs. 8.8%; P = 0.832) and dn-DSA formation (4.9% vs. 5.4%, P = 0.44) were not significantly different between groups. Kaplan-Meier curve analysis demonstrated that the graft survivals of two groups were comparable (P = 0.857). After adjusting for patients’ age, sex, PRA, HLA mismatch confounders, and the use of corticoids, the multivariate Cox regression analysis showed that methods of induction therapy were not associated with clinically-suspected acute rejection and graft survival (both P > 0.05). The incidences of complications (infections, pneumonia, liver injury and myelosuppression) were all comparable between groups (all P > 0.05). These results suggested that rATG could be a safe and efficient immunosuppressant when used in a Chinese recipient population with a higher immunological risk in living donor renal transplantation.

A retrospective statistical analysis of primary hyperoxaluria type 1 (PH1) in children from June 2016 to May 2019 was carried out to discover its clinical and molecular biological characteristics. Patients were divided into two groups (infant and noninfant) according to clinic type. There were 13 pediatric patients (male:female = 6:7) with PH1 in the cohort from 11 families (four of which were biological siblings from two families), whose median age of symptom onset was 12 months and median confirmed diagnosis age was 14 months. Infant type (6 patients) was the most common type. The infant type mortality rate (100%) was higher than the noninfant (14.3%) (p = 0.029). The incidence of renal failure in infant patients was 67%, while the noninfant was 14.3%. 8 of 10 patients with nephrocalcinosis (NC) (76.92%, 10/13) were diagnosed by radiological imaging examinations, including X-ray (3 patients), CT (4 patients) and MRI (1 patient). NC was an independent risk factor for renal insufficiency [OR 3.33, 95% CI (0.7–1.2)], p < 0.05). Nine types of AGXT gene mutations were found; 1 type, c.190A > T, were first reported here. The most common AGXT gene mutation was c.679_680del, which occurred in exon 6 (5 patients). The infant type is the most common type of pediatric PH, with a relatively higher ratio of renal failure at symptom onset and poor prognosis. NC is an independent risk factor leading to renal failure, and radiological imaging examination is recommended for patients with abnormal ultrasound examination to identify NC. AGXT gene detection is important for the diagnosis and treatment of PH1 in children.

Background: The extent and depth of BK polyomavirus (BKPyV) infection in renal allograft correlate with prognosis. This study was designed to evaluate the value of urinary sediment double-immunostaining for predicting BKPyV infection in proximal tubular epithelium. Materials and methods: A total of 76 urine sediment cell blocks, as well as the corresponding transplanted kidney tissues with BK polyomavirus associated-nephropathy (BKPyVAN), were evaluated by automatic double-immunostaining with anti-58-kDa Golgi protein (58K, a proximal renal tubular marker) + anti-SV40-T and anti-homogentisate 1, 2-dioxygenase (HGD, a renal tubular marker) + anti-SV40-T. Results: Immunohistochemical staining demonstrated that 58K was expressed in proximal tubular epithelium but not in distal tubular epithelium or transitional epithelium. Of the 76 patients, 28 (36.8%) had urinary 58K(+)/SV40-T(+) cells and HGD(+)/SV40-T(+) cells, 41 (53.9%) had only HGD(+)/SV40-T(+) cells, one (1.3%) had only 58K(+)/SV40-T(+) cells, and six (7.9%) had only 58K(−)/HGD(−)/SV40-T(+) cells. The presence of urinary 58K(+)/SV40-T(+) cells was correlated with BKPyV infection in proximal tubular epithelium (P < 0.001, r = 0.806). The mean extent of SV40-T staining was significantly more extensive in patients with urinary 58K(+)/SV40-T(+) cells than those without urinary 58K(+)/SV40-T(+) cells (21.4 vs. 12.0%, P < 0.001). The positive predictive value, negative predictive value, sensitivity, and specificity of urinary 58K(+)/SV40-T(+) cells for predicting BKPyV infection in proximal tubular epithelium were 89.7% (95% CI: 71.5–97.3%), 91.5% (95% CI: 78.7–97.2%), 86.7% (95% CI: 68.4–95.6%), and 93.5% (95% CI: 81.1–98.3%), respectively. Conclusion: Urinary sediment double-immunostaining with anti-58K and anti-SV40-T is valuable for predicting the extent and depth of BKPyV infection in renal allograft.

Aim: The aim of this study is to investigate the clinical features of graft dysfunction following living kidney transplantation and to assess its causes. Methods: We retrospectively analyzed a series of 366 living kidney transplantation indication biopsies with a clear etiology and diagnosis from July 2003 to June 2016 at our center. The classifications and diagnoses were performed based on clinical and pathological characteristics. All biopsies were evaluated according to the Banff 2007 schema. Results: Acute rejection (AR) occurred in 85 cases (22.0%), chronic rejection (CR) in 62 cases (16.1%), borderline rejection (BR) in 12 cases (3.1%), calcineurin inhibitor (CNI) toxicity damage in 41 cases (10.6%), BK virus-associated nephropathy (BKVAN) in 43 cases (11.1%), de novo or recurrent renal diseases in 134 cases (34.7%), and other causes in nine cases (2.3%); additionally, 20 cases had two simultaneous causes. The 80 cases with IgA nephropathy (IgAN) had the highest incidence (59.7%) of de novo or recurrent renal diseases. After a mean ± SD follow up of 3.7 ± 2.3 years, the 5-year graft cumulative survival rates of AR, CR, CNI toxicity, BKVAN, and de novo or recurrent renal diseases were 60.1%, 31.2%, 66.6%, 66.9%, and 67.1%, respectively. Conclusions: A biopsy is helpful for the diagnosis of graft dysfunction. De novo or recurrent renal disease, represented by IgAN, is a major cause of graft dysfunction following living kidney transplantation.