Tuberculosis (TB) of the genitourinary system is a rare form of extrapulmonary TB. Testicular TB is particularly uncommon among kidney transplantation (KT) recipients. Diagnosing testicular TB is challenging due to the nonspecific nature of clinical presentations and ambiguous imaging results. In this report, we describe a case involving a 36-year-old male KT recipient who presented with left scrotal pain. He had undergone a living donor KT 8 years prior and was receiving tacrolimus, mycophenolate mofetil, and prednisolone. Laboratory tests revealed anemia, leukocytosis, and elevated inflammatory markers. Computed tomography showed left scrotal wall thickening and enlargement, suggestive of a left testicular abscess. We discontinued mycophenolate mofetil and administered intravenous antibiotics. Additionally, we performed an incision and drainage of the abscess. However, there was no improvement in his clinical course. Consequently, we performed a radical left orchiectomy. The biopsy revealed extensive chronic granulomatous inflammation with caseous necrosis, consistent with tuberculous orchiepididymitis. A quadruple anti-TB regimen was administered, leading to an improvement in the patient's condition. To the best of our knowledge, this is the first reported case of testicular TB without other organ involvement in KT recipients. Including testicular TB in the differential diagnosis of testicular infections and masses is necessary to avoid unnecessary surgical procedures.

As a genetic disease, there has been a long-standing effort to identify therapeutic options for autosomal dominant polycystic kidney disease (ADPKD). Following the development of tolvaptan, a vasopressin 2 receptor antagonist, the treatment strategy for ADPKD patients with rapid disease progression has been changed with a disease-targeted approach. Tolvaptan showed significant efficacy in preserving kidney function and reducing the total kidney volume (TKV) growth rate. These effects were especially pronounced in patients with more severe clinical phenotypes, such as higher TKV and rapidly declining kidney function. Despite the therapeutic effects of tolvaptan, aquaretic symptoms are unavoidable side effects related to the mechanism of the drug and are also directly related to the quality of life. A shared decision-making process could be a valuable strategy for reducing the incidence of side effects and improving medication adherence. Herein, we aimed to review overall clinical trials for applying tolvaptan and suggest important factors during the shared decision-making process.

Generally, an induction agent is chosen based on the conditions of the deceased donor and the recipient. Antithymocyte globulin (ATG) is preferred in relatively high-risk conditions. No clear evidence indicates which induction agent is safer or more efficient for deceased donor kidney transplantation (DDKT). This study compares the efficacy and safety of basiliximab (BSX) and ATG according to donor characteristics in DDKT. Methods: A total of 724 kidney transplant recipients from three transplant centers were enrolled, and propensity score matching was performed. Based on a donor age of 60 years, donor kidney with acute kidney injury (AKI), and Kidney Donor Profile Index (KDPI) score of 65%, we investigated how the choice of induction therapy agent affected the posttransplant clinical outcomes of delayed graft function (DGF), acute rejection (AR), infectious complications, and allograft and patient survival. Results: AR and DGF did not differ significantly according to induction agent in elderly/young donor, AKIon-AKI, and high-KDPI/ low-KDPI subgroups. The infection rate did not show meaningful differences. The differences in death-censored allograft survival and patient survival rates between induction agents were not statistically significant. Conclusion: Our study suggests that BSX can produce clinical outcomes similarly favorable to those of ATG even in DDKT cases with relatively poor donor conditions. Nonetheless, the donor and recipient conditions, immunological risk, and infection risk must be all taken into consideration when choosing an induction agent. Therefore, clinicians should carefully select the induction therapy agent for DDKT based on the risks and benefits in each DDKT case.

Background: Factors related to the development and severity of polycystic liver disease (PLD) have not been well established. We aimed to evaluate the genetic and epidemiologic risk factors of PLD in patients with autosomal dominant polycystic kidney disease (ADPKD). Methods: Adult patients with inherited cystic kidney disease were enrolled from May 2019 to May 2021. Demographic, clinical, and laboratory data were collected at the initial study visit. The severity of PLD was graded based on the height-adjusted total liver volume: < 1,000 mL/m (Gr1), 1,000–1,800 mL/m (Gr2), and > 1,800 mL/m (Gr3). Targeted exome sequencing was done by a gene panel including 89 ciliopathy-related genes. We searched out the relative factors to the presence and the severity of PLD using logistic regression analysis. Results: Of 602 patients with typical ADPKD, 461 (76.6%) patients had PLD. The patients with PLD showed female predominance and a higher frequency of other ADPKD-related complications. The genetic variants with truncating mutation of PKD1 (PKD1-proteintruncating [PT]) or PKD2 commonly affected the development and severity of PLD. An older age, female sex, and higher kidney volume with Mayo classification 1C-1E was significantly associated with the development of PLD, but not with the severity of PLD. On the other hand, higher body mass index, lower hemoglobin, and higher alkaline phosphatase (ALP) were the significant risk factors of severe PLD (≥ Gr2). Conclusion Hepatic involvement in ADPKD could be related to kidney manifestations and genetic variants including PKD1-PT or PKD2. Monitoring hemoglobin and ALP and evaluating the genetic variants might help predict severe PLD.

Tolvaptan reduces height-adjusted total kidney volume (htTKV) and renal function decline in autosomal dominant polycystic kidney disease (ADPKD). This study was aimed at investigating the efficacy and safety of tolvaptan in Korean patients with ADPKD during the titration period. Methods: This study is a multicenter, single-arm, open-label phase 4 study. We enrolled 108 patients with ADPKD (age, 19–50 years) with an estimated glomerular filtration rate (eGFR) of >30 mL/min/1.73 m2 and factors defined as indicative of rapid disease progression. After tolvaptan titration, we evaluated efficacy and side effects and assessed factors associated with the effects. Results: After titration for 4 weeks, eGFR and htTKV decreased by 6.4 ± 7.9 mL/min/1.73 m2 and 16 ± 45 mL/m, respectively. No serious adverse drug reactions were observed during the titration period. The greatest eGFR decline was observed in the first week, with a starting tolvaptan dose of 45 mg. Multivariate linear regression for htTKV decline showed that the greater the change in urine osmolality (Uosm), the greater the decrease in htTKV (β, 0.436; p = 0.009) in the 1D group stratified by the Mayo Clinic image classification. Higher baseline eGFR was related to a higher htTKV reduction rate in the 1E group (β, –0.642; p = 0.009). Conclusion: We observed short-term effects and safety during the tolvaptan titration period. The decline of htTKV can be predicted as a short-term effect of tolvaptan by observing Uosm changes from baseline to end of titration in 1D and baseline eGFR in 1E groups.

Identifying genetic mutations in individuals with inherited cystic kidney disease is necessary for precise treatment. We aimed to elucidate the genetic characteristics of cystic kidney disease in the Korean population. Methods: We conducted a 3-year prospective, multicenter cohort study at eight hospitals from May 2019 to May 2022. Patients with more than three renal cysts were enrolled and classified into two categories, typical autosomal dominant polycystic kidney disease (ADPKD) and atypical PKD. We identified the clinical characteristics and performed a genetic analysis using a targeted gene panel. Results: A total of 725 adult patients were included in the study, of which 560 (77.2%) were diagnosed with typical ADPKD and 165 (22.8%) had atypical PKD. Among the typical ADPKD cases, the Mayo imaging classification was as follows: 1A (55, 9.9%), 1B (149, 26.6%), 1C (198, 35.8%), 1D (90, 16.3%), and 1E (61, 11.0%). The atypical PKD cases were classified as bilateral cystic with bilateral atrophic (31, 37.3%), lopsided (27, 32.5%), unilateral (nine, 10.8%), segmental (eight, 9.6%), bilateral cystic with unilateral atrophic (seven, 8.4%), and asymmetric (one, 1.2%). Pathogenic variants were found in 64.3% of the patients using the ciliopathy-related targeted gene panel. The typical ADPKD group demonstrated a higher discovery rate (62.3%) than the atypical PKD group (41.8%). Conclusion: We present a nationwide genetic cohort’s baseline clinical and genetic characteristics for Korean cystic kidney disease.

Tolvaptan, a non-peptide arginine vasopressin V2 receptor antagonist, is a newly developed drug to reduce kidney volume and preserve kidney function in autosomal dominant polycystic kidney disease (ADPKD) patients. We aimed to evaluate the descriptive characteristics of patients according to the use of tolvaptan. Also, we tried to find the efficacy of tolvaptan on kidney volume and kidney function. We included patients with ADPKD who visited a tertiary hospital in South Korea during Sep. 2018 and Apr. 2022. The data was acquired from the Electric Medical Records system. A total of 64 patients were included in the study, and there were 33 (51.6%) patients taking tolvaptan during follow-up periods. During 17.8 ± 13.1 months of follow-up periods, estimated glomerular filtration rate (eGFR) changes were 89.4% compared to the baseline eGFR. Although the latest eGFR was lower in patients with tolvaptan (55.9 ± 24.7 mL/min/1.73 m2) than without tolvaptan (68.4 ± 35.1 mL/min/1.73 m2), there was no statistical significance (p = 0.108). We found that the mean change of height-adjusted total kidney volume (HtTKV) was -2.7% based on the baseline HtTKV in patients taking tolvaptan for more than 1-year. Although there was no statistical significance, the mean change of HtTKV was the highest in patients with 1E of Mayo classification (-4.3%). To anticipate the solid data on the efficacy of tolvaptan in the Asian population, more aggressive efforts are needed to search for suitable patients accompanied by appropriate monitoring over a more extended period.

Chronic kidney disease (CKD) is a common condition leading to renal dysfunction and is closely related to increased cardiovascular and mortality risk. CKD is an important public health issue, and recent genetic studies have verified common CKD susceptibility variants. This research examines the interrelationship between candidate genes polymorphisms of interferon lambda (IFNL) induction, its signaling pathway, and CKD. Methods: Seventy-five patients with advanced CKD and 312 healthy subjects (as controls) participated in this research. A replication set composed of 172 patients with advanced CKD and 365 controls was used for additional analysis. The genotype of single nucleotide polymorphisms (SNPs) was determined by the Axiom Genome-Wide Human Assay and SNaPshot assay. Results: The SNP of IFNL3 was significantly associated with CKD in the codominant (p = 0.02) and dominant models (p = 0.02). In addition, the SNPs of IFNL2 were significantly associated with CKD in the dominant model (p = 0.03), and the SNP of interferon alpha receptor 2 (IFNAR2) was significantly associated with CKD in the log-additive model (p = 0.03). Concerning rs148543092, in the IFNL3 gene, a significant association was observed after pooling the original and replication sets. Conclusion: These results indicate that SNPs in the IFNL induction and signal pathway may be associated with CKD risk in the Korean population. Finally, our results also show that the IFNL3 gene variant may be associated with CKD risk.

Background/Aims: Renal recovery of a kidney donor after undergoing nephrectomy though challenging is essential. We aimed to examine the effect of estimated glomerular filtration rate (eGFR) percent change at 1-month post-donation on insufficient kidney function after kidney donation. Methods: A total of 3,952 living kidney donors who underwent donor nephrectomy from 1982 to 2019 from eight different tertiary hospitals in Korea were initially screened. Percent changes in the eGFR from baseline to 1-month post-donation were calculated. The degree of percent changes was categorized by quartile, and the 1st quartile was regarded as the group with the lowest decreased eGFR at 1-month after donation. The remaining eGFR less than 60 mL/min/1.73 m2 was the end-point. The Cox proportional hazard model was used for evaluating the impact of initial eGFR and eGFR percent change at 1-month post-donation on the condition with remaining eGFR < 60 mL/ min/1.73 m2. In the multivariate analysis, we used variables with a p < 0.1 in the univariate analysis. Results: A total of 1,585 donors were included in the analysis. During 62.2 ± 49.3 months, 13.7% of donors showed renal insufficiency. The 4th (adjusted hazard ratio [aHR], 10.41; 95% confidence interval [CI], 5.15 to 21.04) and the 3rd (aHR, 4.29; 95% CI, 2.15 to 8.56) quartiles of percent change in eGFR and the pre-donation eGFR (aHR, 0.90; 95% CI, 0.88 to 0.92) were associated with the development of renal insufficiency. Conclusions The impact of worse initial renal recovery on renal insufficiency was pronounced in donors with lower pre-donation eGFRs. Additionally, worse initial renal recovery of remaining kidney affected the long-term development of renal insufficiency in kidney donors.