{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T13:07:51Z","timestamp":1780664871960,"version":"3.54.1"},"reference-count":18,"publisher":"BMJ","issue":"6","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2026,4,17]]},"published-print":{"date-parts":[[2026,6]]},"abstract":"<jats:p>\n                    T-cell large granular lymphocyte leukaemia (T-LGLL) is a chronic lymphoproliferative disorder often associated with pure red cell aplasia (PRCA). We report a unique case of a woman in her 50s presenting with PRCA secondary to T-LGLL, in which targeted next-generation sequencing identified a somatic\n                    <jats:italic>STAT3<\/jats:italic>\n                    P715L mutation. This variant, previously described only in germline mutation in\n                    <jats:italic>STAT3<\/jats:italic>\n                    gain-of-function syndrome, has not been reported as a somatic mutation in T-LGLL. Immunohistochemical analysis revealed constitutive STAT3 (signal transducer and activator of transcription 3) activation in clonal CD8\n                    <jats:sup>+<\/jats:sup>\n                    T cells, suggesting a pathogenic role for the P715L mutation. The patient responded to ciclosporin therapy with gradual haematological improvement and became transfusion-independent within 6\u2009months. This case highlights the importance of molecular profiling in T-LGLL presentations and expands the known mutational spectrum of\n                    <jats:italic>STAT3<\/jats:italic>\n                    . It also raises the possibility that non-SH2 (Src homology 2) domain\n                    <jats:italic>STAT3<\/jats:italic>\n                    mutations may contribute to disease pathogenesis and influence treatment response in T-LGLL.\n                  <\/jats:p>","DOI":"10.1136\/bcr-2025-268958","type":"journal-article","created":{"date-parts":[[2026,6,5]],"date-time":"2026-06-05T12:25:17Z","timestamp":1780662317000},"page":"e268958","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["T-cell large granular lymphocyte leukaemia with pure red cell aplasia harbouring a somatic\n                    <i>STAT3<\/i>\n                    P715L mutation"],"prefix":"10.1136","volume":"19","author":[{"given":"Yusuke","family":"Okamoto","sequence":"first","affiliation":[{"name":"Department of Hematology, Kyoto University Graduate School of Medicine Faculty of Medicine, Kyoto, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9377-2098","authenticated-orcid":false,"given":"Kenichi","family":"Ishiyama","sequence":"additional","affiliation":[{"name":"Department of Hematology, Kyoto University Graduate School of Medicine Faculty of Medicine, Kyoto, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kazuhisa","family":"Chonabayashi","sequence":"additional","affiliation":[{"name":"Department of Hematology, Kyoto University Graduate School of Medicine Faculty of Medicine, Kyoto, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Junya","family":"Kanda","sequence":"additional","affiliation":[{"name":"Department of Hematology, Kyoto University Graduate School of Medicine Faculty of Medicine, Kyoto, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9784-1487","authenticated-orcid":false,"given":"Munenori","family":"Kawai","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine Faculty of Medicine, Kyoto, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Akihisa","family":"Fukuda","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology and Hepatology, Kyoto University Graduate School of Medicine Faculty of Medicine, Kyoto, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yasuhito","family":"Nannya","sequence":"additional","affiliation":[{"name":"Department of Pathology and Tumor Biology, Kyoto University, Kyoto, Japan"},{"name":"Division of Hematopoietic Disease Control, The University of Tokyo, Tokyo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Seishi","family":"Ogawa","sequence":"additional","affiliation":[{"name":"Department of Pathology and Tumor Biology, Kyoto University, Kyoto, Japan"},{"name":"Institute for the Advanced Study of Human Biology (WPI-ASHBi), Kyoto University, Kyoto, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kouhei","family":"Yamashita","sequence":"additional","affiliation":[{"name":"Department of Hematology, Kyoto University Graduate School of Medicine Faculty of Medicine, Kyoto, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Akifumi","family":"Takaori","sequence":"additional","affiliation":[{"name":"Department of Hematology, Kyoto University Graduate School of Medicine Faculty of Medicine, Kyoto, 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