The coronavirus disease 2019 (COVID-19) vaccination campaign has progressed worldwide. Rare but severe adverse events of COVID-19 vaccination such as anaphylaxis and myocarditis have begun to be noticed. Of note, several cases of new-onset antineutrophil cytoplasmic antibody-associated vasculitis (AAV) after COVID-19 mRNA vaccination have been reported. In contrast, relapse of AAV in remission has not been recognized enough as an adverse outcome of COVID-19 vaccination. We report, to the best of our knowledge, a first case of renal-limited AAV in remission using every 6-month rituximab administration that relapsed with pulmonary hemorrhage, but not glomerulonephritis, following the first dose of the COVID-19 vaccine. Notably, the patient received the COVID-19 vaccine more than 6 months after the last dose of rituximab according to the recommendations. Ironically, his CD19 positive B cell counts were found to be increased after admission, indicating that our case might have been prone to relapse after COVID-19 vaccination. Although our case cannot establish causality between AAV relapse and COVID-19 mRNA vaccination, a clinical vigilance for relapse of AAV especially in patients undergoing rituximab maintenance therapy following COVID-19 vaccination should be maintained. Furthermore, the elapsed time between rituximab administration and COVID-19 mRNA vaccination should be carefully adjusted based on AAV disease-activity (Nishioka et al. Front Med 2022. in press).

Background: Transcatheter aortic valve implantation (TAVI) has evolved to be a treatment of choice in high-risk patients with aortic stenosis (AS). However, it is not known whether TAVI is safe and beneficial for the creation of arteriovenous fistula for maintenance hemodialysis in high-risk patients with severe AS. Case presentation: A 91-year-old woman was referred to our hospital due to oligoanuria and progressive renal dysfunction. She was diagnosed with anti-glomerular basement membrane (GBM) disease. She had hypertension, chronic kidney disease stage G3b, and AS. We chose not to perform immunosuppressive therapy and plasmapheresis for anti-GBM disease because the risk of death outweighed the benefit of treatment. Hemodialysis with a venous catheter was initiated for the renal indication. As she showed severe AS, she had a risk of cardiac decompensation after arteriovenous fistula creation for dialysis. Following the clinical decision-making process, she underwent TAVI. Although she required the implantation of a cardiac pacemaker for an advanced atrioventricular block that occurred 11 days after TAVI, arteriovenous fistula was successfully created thereafter. She could undergo maintenance hemodialysis using arteriovenous fistula. Conclusions: TAVI is safe and beneficial for the creation of arteriovenous fistula shortly after initiating acute hemodialysis using a catheter in a very old patient with anti-GBM disease.

Background and Aim: Pendrin is a Cl/HCO3 exchanger that is selectively present at the apical membrane in non-α intercalated cells of the renal tubules in the kidney. Besides its role in acid/base homeostasis, accumulating studies provided evidence that pendrin regulates extracellular fluid volume and electrolyte balance. Experimental studies using animal models also indicate that pendrin is upregulated in a high aldosterone state, along with the induction of NaCl cotransporter and epithelial Na channel. However, the regulation of pendrin in human is unclear. The present study was conducted to examine the levels of pendrin in subjects with primary aldosteronism. Methods: Sixteen patients who were diagnosed as primary aldosteronism at Teikyo University Hospital and Yokohama Rosai Hospital were enrolled in this study. We isolated exosomes from pre- and post-treatment urine samples by the ultracentrifugation method, and the levels of pendrin was evaluated by Western blotting. The loading amount was adjusted by creatinine concentration. Purification of exosomal fraction was confirmed by electron microscopy and also by the presence of alix, a marker of exosome. Results and Discussion: Among 16 patients, six received unilateral adrenalectomy and 10 received MR antagonist as the treatment. Mean aldosterone-to renin ratio was 1085. We excluded two subjects because alix was not detected in the pre-treatment samples, and the analysis was done in 14 subjects. In human urine, pendrin was detected at ~110kDa and ~220kDa, the latter likely representing a dimer. We found that pendrin abundance was significantly reduced by 49.8% (P<0.01) in post-treatment samples compared with pre-treatment samples. Therefore, pendrin is altered in primary aldosteronism, likely contributing to the pathophysiology of aldosterone excess in humans.