COVID-19 and renal allograft rejection: insight from controlled and non-controlled studies.

AIM: Kidney transplant recipients (KTRs), due to their immunosuppressed status, are potentially more susceptible to both the severe effects of COVID-19 and complications in their transplanted organ. The aim of this study is to investigate whether COVID-19 infection increases the risk of rejection in kidney transplant recipients (KTRs). METHODS: This study involved a detailed literature review, conducted using PubMed, with the search being completed by September 7th, 2023. The search strategy incorporated a combination of relevant keywords: 'COVID', 'Renal', 'Kidney', 'Transplant', and 'Rejection'. The results from controlled and uncontrolled studies were separately collated and analyzed. RESULTS: A total of 11 studies were identified, encompassing 1,179 patients. Among these, two controlled studies reported the incidence of rejection in KTRs infected with COVID-19. Pooling data from these studies revealed no significant statistical correlation between COVID-19 infection and biopsy-proven rejection (p = 0.26). In addition, nine non-controlled studies were found, with rejection incidences ranging from 0% to 66.7%. The majority of these studies (eight out of nine) had small sample sizes, ranging from 3 to 75 KTRs, while the largest included 372 KTRs. The combined rejection rate across these studies was calculated to be 11.8%. CONCLUSION: In conclusion, the limited number of published controlled studies revealed no statistically significant association between COVID-19 infection and biopsy-proven rejection among KTRs. However, the broader analysis of non-controlled studies showed a variable rejection incidence with a pooled rejection rate of 11.8%. There is insufficient high-quality data to explore the association of COVID-19 infection and rejection.

Intravenous Tranexamic Acid in Percutaneous Kidney Biopsy: A Randomized Controlled Trial.

BACKGROUND: Tranexamic acid is frequently reported to reduce bleeding-related complications in major surgery and trauma. We aimed to investigate whether tranexamic acid reduced hematoma size after percutaneous kidney biopsy. METHODS: We conducted a double-blind, parallel three-group, randomized placebo-controlled trial at a teaching hospital in Japan between January 2016 and July 2018. Adult patients with clinical indication for ultrasound-guided percutaneous biopsy of a native kidney were included. Participants were randomly assigned into three groups: high-dose tranexamic acid (1,000 mg in total), low-dose tranexamic acid (500 mg in total), or placebo (counterpart saline). Intervention drugs were intravenously administered twice, as a bolus just before the biopsy and as a continuous infusion initiated just after the biopsy. Primary outcome was post-biopsy perirenal hematoma size as measured by ultrasound on the morning after the biopsy. RESULTS: We assessed 90 adult patients for study eligibility, of whom 56 were randomly allocated into the three groups: 20 for high-dose tranexamic acid, 19 for low-dose tranexamic acid, and 17 for placebo. The median size of perirenal hematoma was 200 mm2 (interquartile range, 21-650) in the high-dose tranexamic acid group, 52 mm2 (0-139) in the low-dose tranexamic acid group, and 0 mm2 (0-339) in the placebo group (p = 0.048 for high-dose tranexamic acid vs. placebo). CONCLUSION: In this trial, the median size of post-kidney biopsy hematoma was unexpectedly larger in the high-dose tranexamic acid group than in the placebo group. Although our results do not support the routine use of tranexamic acid in percutaneous kidney biopsy at present, further studies are needed to confirm the results.

BK viral infection: A review of management and treatment.

BK viral infection remains to be a challenging post-transplant infection, which can result in kidney dysfunction. The mainstay approach to BK infection is reduction of immunosuppression. Alterations in immunosuppressive regimen with minimization of calcineurin inhibitors, use of mechanistic target of rapamycin inhibitors, and leflunomide have been attempted with variable outcomes. Over the past few years, investigators have explored potential therapeutic options for BK infection. Fluoroquinolone prophylaxis and treatment was found to have no benefit in kidney transplant recipients. The utility of cidofovir is limited by its nephrotoxicity. Intravenous immunoglobulin is becoming a popular option for treatment and prophylaxis for BK infection, as it increases the neutralizing antibody titers against the most common BK virus serotypes. Virus-specific T cell therapy is an emerging treatment option for BK viremia. In this review, we will explore management and therapeutic options for BK infection and recent evidence available in literature.

[A case of right femoral artery thromboembolism in steroid-dependent nephrotic syndrome].

A 37-year-old man diagnosed with minimal change nephrotic syndrome at the age of 17, was admitted to hospital with leg pain. He had relapsed nephrotic syndrome and thromboembolism of the right femoral and middle cerebral arteries. He was treated with steroid pulse therapy and thrombectomy. Right lower extremity necrosis developed and a below-knee amputation was performed. His nephrotic syndrome and the amputated lower extremity necrosis subsequently improved. Arterial thrombosis is a rare complication of nephrotic syndrome; however, it is a severe complication. Prophylactic anticoagulation should be considered in patients with an increased risk of thrombosis.

Carotid thromboembolism associated with nephrotic syndrome treated with dabigatran.

Nephrotic syndrome (NS) may be complicated by thromboembolism, which occasionally manifests as stroke. Although the optimal, standardized approach to the prophylaxis and management of thromboembolic complications associated with NS has not been established, anticoagulation with heparin and subsequent warfarin is the de facto standard of treatment. Dabigatran, a novel direct thrombin inhibitor, has become a substitute for warfarin and heparin for many indications, including the prophylaxis of stroke associated with nonvalvular atrial fibrillation and postoperative thromboprophylaxis in orthopedic patients. We report a 35-year-old male with NS due to membranous nephropathy (MN) that presented with carotid thromboembolism. Because the patient developed drug-induced hepatitis due to warfarin, we attempted treatment with dabigatran and were successful in continuing the medication without any complications. We also reviewed the literature on stroke associated with NS. Twenty-one prior cases have been reported, and the review of these cases revealed some interesting points. The age of onset ranged from 19 to 59 years. Most of the reported cases sustained a stroke at earlier ages than patients with atherosclerosis and atrial fibrillation, which suggests that NS may independently predispose individuals to arterial and venous thromboses. MN was the most common underlying pathology. Given that a standardized approach to the prophylaxis and management of thrombotic complications associated with NS has not been established, our experience suggests that dabigatran is a valid new treatment option for thrombotic complications of NS.

Rate acceleration of organic reaction by immediate solvent evaporation.

Several types of organic reactions were accelerated by immediate evaporation of solvents because of remarkable enhancement of molecule-to-molecule contacts between reactants.