{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T15:51:20Z","timestamp":1782489080100,"version":"3.54.5"},"reference-count":13,"publisher":"BMJ","issue":"4","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2026,3,30]]},"published-print":{"date-parts":[[2026,4]]},"abstract":"<jats:p>\n                    Progressive multifocal leukoencephalopathy (PML), caused by reactivation of JC virus, typically develops in individuals with profound immunosuppression, but may also occur in those with more subtle immune dysregulation. We report the case of a woman in her 40s with autoimmune hepatitis-primary biliary cholangitis overlap syndrome who was receiving long-term low-dose corticosteroid therapy. Despite preserved CD4\n                    <jats:sup>+<\/jats:sup>\n                    and CD8\n                    <jats:sup>+<\/jats:sup>\n                    T-cell counts, she developed cerebellar symptoms with MRI findings consistent with PML, and JC viral DNA was detected in cerebrospinal fluid. Immunophenotyping revealed marked CD19\n                    <jats:sup>+<\/jats:sup>\n                    B-cell lymphopenia, polyclonal hypergammaglobulinaemia and raised free light chains, suggesting functional immunodeficiency despite numerically preserved T-cell subsets.\n                  <\/jats:p>\n                  <jats:p>This case is educationally important as it highlights the diagnostic challenge of recognising PML in patients with apparently preserved T-cell counts, the value of extended immune profiling (B-cell enumeration and immunoglobulin characterisation) in atypical presentations and the therapeutic dilemmas that arise when balancing immune recovery against control of autoimmune disease.<\/jats:p>","DOI":"10.1136\/bcr-2025-267787","type":"journal-article","created":{"date-parts":[[2026,4,10]],"date-time":"2026-04-10T17:30:24Z","timestamp":1775842224000},"page":"e267787","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":1,"title":["Progressive multifocal leukoencephalopathy associated with immune dysregulation"],"prefix":"10.1136","volume":"19","author":[{"given":"Odunayo","family":"Yusuf","sequence":"first","affiliation":[{"name":"Internal Medicine, Manchester University NHS Foundation Trust, Manchester, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-4599-7737","authenticated-orcid":false,"given":"Mai","family":"Elrayes","sequence":"additional","affiliation":[{"name":"Neurology, Salford Royal Hospital Manchester Centre for Clinical Neurosciences, Salford, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-1542-3841","authenticated-orcid":false,"given":"Khuloud","family":"Elsabbagh","sequence":"additional","affiliation":[{"name":"Neurology, Salford Royal Hospital Manchester Centre for Clinical Neurosciences, Salford, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amit","family":"Herwadkar","sequence":"additional","affiliation":[{"name":"Salford Royal Hospitals NHS Trust, Salford, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Phoebe","family":"Shellman","sequence":"additional","affiliation":[{"name":"Infectious Diseases, Manchester University NHS Foundation Trust, Manchester, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katie","family":"Hughes","sequence":"additional","affiliation":[{"name":"Infectious Diseases, Manchester University NHS Foundation Trust, Manchester, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alison","family":"Uriel","sequence":"additional","affiliation":[{"name":"Infectious Diseases, Manchester University NHS Foundation Trust, Manchester, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nazar","family":"Sharaf","sequence":"additional","affiliation":[{"name":"Neurology, Salford Royal NHS Foundation Trust Greater Manchester Neuroscience Centre, Salford, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,4,10]]},"reference":[{"key":"2026062608153558000_19.4.e267787.1","doi-asserted-by":"publisher","DOI":"10.1007\/s11910-007-0072-9"},{"key":"2026062608153558000_19.4.e267787.2","doi-asserted-by":"publisher","DOI":"10.1016\/S1474-4422(10)70040-5"},{"key":"2026062608153558000_19.4.e267787.3","doi-asserted-by":"publisher","DOI":"10.1002\/ana.22408"},{"key":"2026062608153558000_19.4.e267787.4","doi-asserted-by":"publisher","DOI":"10.1016\/S1474-4422(10)70040-5"},{"key":"2026062608153558000_19.4.e267787.5","doi-asserted-by":"publisher","DOI":"10.1038\/s41582-020-00427-y"},{"key":"2026062608153558000_19.4.e267787.6","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1093\/cid\/ciy030","article-title":"Diagnostic and Prognostic Value of JC Virus DNA in Plasma in Progressive Multifocal Leukoencephalopathy","volume":"67","author":"Ferretti","year":"2018","journal-title":"Clin Infect Dis"},{"key":"2026062608153558000_19.4.e267787.7","first-page":"28","article-title":"Expansion of atypical memory B cells is a prominent feature of autoimmune liver diseases","volume":"172","author":"Oliviero","year":"2013","journal-title":"Clin Exp Immunol"},{"key":"2026062608153558000_19.4.e267787.8","doi-asserted-by":"crossref","unstructured":"Czaja AJ . Autoantibodies as prognostic markers in autoimmune liver disease. Dig Dis Sci 2012;57. doi:10.1007\/s10620-012-2179-3","DOI":"10.1007\/s10620-012-2179-3"},{"key":"2026062608153558000_19.4.e267787.9","doi-asserted-by":"crossref","first-page":"1061","DOI":"10.1212\/WNL.0b013e31822e55e7","article-title":"Immune reconstitution inflammatory syndrome in natalizumab-associated PML","volume":"77","author":"Tan","year":"2011","journal-title":"Neurology (ECronicon)"},{"key":"2026062608153558000_19.4.e267787.10","first-page":"9","article-title":"Frequent infection of cerebellar granule cell neurons by JC virus in progressive multifocal leukoencephalopathy","volume":"83","author":"W\u00fcthrich","year":"2009","journal-title":"J Virol"},{"key":"2026062608153558000_19.4.e267787.11","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1212\/WNL.0b013e318225ab3f","article-title":"Progressive multifocal leukoencephalopathy in a patient without immunodeficiency","volume":"77","author":"Tan","year":"2011","journal-title":"Neurology (ECronicon)"},{"key":"2026062608153558000_19.4.e267787.12","doi-asserted-by":"publisher","DOI":"10.3389\/fmicb.2013.00115"},{"key":"2026062608153558000_19.4.e267787.13","doi-asserted-by":"crossref","unstructured":"RECOVERY Collaborative Group . Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial. Lancet 2021;2049\u201359. doi:10.1016\/S0140-6736(21)00897-7","DOI":"10.1016\/S0140-6736(21)00897-7"}],"container-title":["BMJ Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bcr-2025-267787","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T15:21:30Z","timestamp":1782487290000},"score":1,"resource":{"primary":{"URL":"https:\/\/casereports.bmj.com\/lookup\/doi\/10.1136\/bcr-2025-267787"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4]]},"references-count":13,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2026,4,10]]},"published-print":{"date-parts":[[2026,4]]}},"alternative-id":["10.1136\/bcr-2025-267787"],"URL":"https:\/\/doi.org\/10.1136\/bcr-2025-267787","relation":{},"ISSN":["1757-790X"],"issn-type":[{"value":"1757-790X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4]]}}}