{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T04:53:52Z","timestamp":1791262432277,"version":"4.1.0"},"reference-count":21,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T00:00:00Z","timestamp":1791244800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Nephrol."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>C4d deposition is common after ABO-incompatible (ABOi) kidney transplantation and, unlike ABO-compatible grafts, is not necessarily indicative of antibody-mediated injury.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Between 2015 and 2022, 254 ABOi kidney transplantations were performed at our center, and 69 recipients with paired 3-month and 1-year protocol biopsies were classified as persistently C4d-positive (n = 54) or C4d-negative\/nonpersistent (n = 15). Pre-transplant background, cellular infiltration, chronic Banff lesions according to the Banff 2019 classification, graft function, and graft survival were compared.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Baseline anti-A\/B titers, ABO combination, donor age, and donor relationship did not differ between the groups, whereas donor sex differed significantly (P = 0.014). Microvascular inflammation, defined as glomerulitis plus peritubular capillaritis \u22652, was observed in 6\/54 recipients (11.1%) versus 1\/15 (6.7%), and chronic changes, defined as interstitial fibrosis score \u22651, were observed in 27\/54 (50.0%) versus 6\/15 (40.0%); none of these differences reached statistical significance. Graft function and survival also did not differ significantly, although all four graft losses occurred in the persistent C4d-positive group. Three of these losses were attributable to chronic active antibody-mediated rejection, diagnosed at the 1-year biopsy in one recipient and later in two recipients.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>Given the selected cohort and limited statistical power, these findings represent a failure to detect an association rather than evidence of equivalence. They are consistent with accommodation but require confirmation in larger, less-selected cohorts.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fneph.2026.1940137","type":"journal-article","created":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T04:25:08Z","timestamp":1791260708000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Clinical significance of persistent C4d deposition on sequential protocol biopsies in ABO-incompatible kidney transplantation"],"prefix":"10.3389","volume":"6","author":[{"given":"Yu","family":"Kijima","sequence":"first","affiliation":[{"name":"Department of Urology, Tokyo Women\u2019s Medical University Hospital","place":["Shinjuku-ku, Tokyo, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hideki","family":"Ishida","sequence":"additional","affiliation":[{"name":"Department of Urology, Tokyo Women\u2019s Medical University 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Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tomokazu","family":"Shimizu","sequence":"additional","affiliation":[{"name":"Department of Urology, Tokyo Women\u2019s Medical University Hospital","place":["Shinjuku-ku, Tokyo, Japan"]},{"name":"Department of Organ Transplant Medicine, Tokyo Women\u2019s Medical University Hospital","place":["Shinjuku-ku, Tokyo, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Toshio","family":"Takagi","sequence":"additional","affiliation":[{"name":"Department of Urology, Tokyo Women\u2019s Medical University Hospital","place":["Shinjuku-ku, Tokyo, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,10,6]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1600-6143.2004.00464.x","article-title":"Excellent long-term outcome of ABO-incompatible living kidney transplantation in 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