{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T12:59:54Z","timestamp":1785157194369,"version":"3.55.0"},"reference-count":19,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T00:00:00Z","timestamp":1785110400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibodies"],"abstract":"<jats:p>Background\/Objectives: Acute interstitial nephritis (AIN) is a cause of acute kidney injury (AKI) during immune checkpoint inhibitor (ICI) therapy, but biopsy-confirmed data are limited. We estimated institutional proportions of biopsy-confirmed AIN clinically attributed to ICI exposure (ICI-AIN) and characterized its presentation, pathology, treatment, and renal outcomes. Methods: We retrospectively reviewed native renal biopsies performed at Attikon University Hospital from February 2021 through December 2025. Cases were included when ICI exposure preceded AKI and the treating nephrology team documented clinicopathologic attribution to ICI exposure. Results: AIN was identified in 15 of 339 native renal biopsies; 12 cases were attributed to ICI exposure, representing 3.5% of native renal biopsies and 0.8% of 1472 unique ICI-treated patients. Median serum creatinine increased from 1.05 mg\/dL at baseline to 3.50 mg\/dL at biopsy assessment. During the AKI episode, 10 patients (83.3%) met Kidney Disease: Improving Global Outcomes (KDIGO) criteria for stage 3 AKI. All patients had pyuria, negative urine cultures, and subnephrotic proteinuria. Hematuria and peripheral eosinophilia occurred in four and two patients, respectively. All patients received corticosteroids, and none required kidney replacement therapy. Complete, partial, and absent recovery occurred in eight, two, and two patients, respectively; under the stricter baseline-relative definition, the corresponding numbers were five, five, and two. Conclusions: Biopsy-confirmed ICI-AIN was infrequently detected. Severe AKI was common, urinary findings were nonspecific, and residual renal dysfunction frequently persisted after corticosteroid treatment.<\/jats:p>","DOI":"10.3390\/antib15040065","type":"journal-article","created":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T11:54:26Z","timestamp":1785153266000},"page":"65","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Biopsy-Confirmed Acute Interstitial Nephritis in Patients Treated with Immune Checkpoint Inhibitors: A Single-Center Retrospective Case Series"],"prefix":"10.3390","volume":"15","author":[{"given":"Ioannis","family":"Ogrotis","sequence":"first","affiliation":[{"name":"Department of Clinical & Interventional Nephrology, 2nd Propaedeutic Clinic of Internal Medicine, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Rimini 1, Chaidari, 12461 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Konstantinos","family":"Drouzas","sequence":"additional","affiliation":[{"name":"Department of Clinical & Interventional Nephrology, 2nd Propaedeutic Clinic of Internal Medicine, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Rimini 1, Chaidari, 12461 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Evangelia","family":"Pantzopoulou","sequence":"additional","affiliation":[{"name":"Department of Clinical & Interventional Nephrology, 2nd Propaedeutic Clinic of Internal Medicine, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Rimini 1, Chaidari, 12461 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8994-5267","authenticated-orcid":false,"given":"Petros","family":"Nikolopoulos","sequence":"additional","affiliation":[{"name":"Department of Clinical & Interventional Nephrology, 2nd Propaedeutic Clinic of Internal Medicine, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Rimini 1, Chaidari, 12461 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ioannis","family":"Kotsantis","sequence":"additional","affiliation":[{"name":"Oncology Department, 2nd Propaedeutic Clinic of Internal Medicine, Attikon University Hospital, National and Kapodistrian University of Athens, Rimini 1, Chaidari, 12461 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amanda","family":"Psyrri","sequence":"additional","affiliation":[{"name":"Oncology Department, 2nd Propaedeutic Clinic of Internal Medicine, Attikon University Hospital, National and Kapodistrian University of Athens, Rimini 1, Chaidari, 12461 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"George","family":"Liapis","sequence":"additional","affiliation":[{"name":"1st Department of Pathology, Medical School, National and Kapodistrian University of Athens and Laikon Hospital, 11527 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1643-8923","authenticated-orcid":false,"given":"Sophia","family":"Lionaki","sequence":"additional","affiliation":[{"name":"Department of Clinical & Interventional Nephrology, 2nd Propaedeutic Clinic of Internal Medicine, Attikon University Hospital, School of Medicine, National and Kapodistrian University of Athens, Rimini 1, Chaidari, 12461 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1350","DOI":"10.1126\/science.aar4060","article-title":"Cancer immunotherapy using checkpoint blockade","volume":"359","author":"Ribas","year":"2018","journal-title":"Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1056\/NEJMra1703481","article-title":"Immune-related adverse events associated with immune checkpoint blockade","volume":"378","author":"Postow","year":"2018","journal-title":"N. 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