{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T09:16:53Z","timestamp":1788513413719,"version":"build-2803163510"},"reference-count":5,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T00:00:00Z","timestamp":1788480000000},"content-version":"vor","delay-in-days":246,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,1,1]],"date-time":"2026-01-01T00:00:00Z","timestamp":1767225600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Case Reports in Hematology"],"published-print":{"date-parts":[[2026,1]]},"abstract":"<jats:p>Hypereosinophilic syndrome (HES) comprises a heterogeneous group of disorders characterized by persistent eosinophilia and eosinophil\u2010mediated organ involvement. Although interleukin\u20105 (IL\u20105) inhibition is an established treatment strategy, some patients experience persistent or recurrent disease despite therapy. Janus kinase (JAK) inhibition has emerged as a potential therapeutic option in refractory cases. We report a 63\u2010year\u2010old White male who presented with a diffuse pruritic erythematous rash, marked leukocytosis with eosinophils comprising approximately 83% of circulating leukocytes, and markedly elevated serum IgE levels. Bone marrow biopsy demonstrated a hypercellular marrow (approximately 89%) with eosinophils accounting for approximately 75% of nucleated cells. Extensive evaluation, including cytogenetic, fluorescence in situ hybridization, and molecular testing for myeloid neoplasms, was unrevealing, while peripheral blood polymerase chain reaction demonstrated a clonal T\u2010cell receptor gene rearrangement. Despite prior hydroxyurea therapy, prolonged treatment with mepolizumab, and repeated corticosteroid courses, the patient developed recurrent disease with an absolute eosinophil count of 2760\/\u03bcL. Ruxolitinib was initiated while IL\u20105 inhibition was continued. Following JAK inhibition, leukocyte and eosinophil counts normalized, corticosteroids were discontinued, and disease control was maintained at 3\u2010month follow\u2010up. This case highlights the potential role of JAK inhibition as adjunctive therapy in refractory HES with clonal T\u2010cell receptor rearrangement. Further studies are needed to define the safety, durability, and optimal integration of JAK inhibition in patients with refractory eosinophilic disorders.<\/jats:p>","DOI":"10.1155\/crh\/9477679","type":"journal-article","created":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T08:57:56Z","timestamp":1788512276000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Refractory Hypereosinophilic Syndrome With Clonal T\u2010Cell Receptor Rearrangement Treated With JAK Inhibition Following Incomplete Response to IL\u20105 Blockade"],"prefix":"10.1155","volume":"2026","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-6133-5698","authenticated-orcid":false,"given":"Kevin Wayne","family":"McKaughan","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-6563-9131","authenticated-orcid":false,"given":"Phu V.","family":"Truong","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-9849-6389","authenticated-orcid":false,"given":"Gregory","family":"Bongers","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,9,4]]},"reference":[{"key":"e_1_2_12_1_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jaci.2012.02.019"},{"key":"e_1_2_12_2_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jaci.2010.04.011"},{"key":"e_1_2_12_3_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.jaci.2020.08.037"},{"key":"e_1_2_12_4_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.immuni.2012.03.014"},{"key":"e_1_2_12_5_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.clim.2023.109275"}],"container-title":["Case Reports in Hematology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1155\/crh\/9477679","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1155\/crh\/9477679","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1155\/crh\/9477679","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T08:57:57Z","timestamp":1788512277000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1155\/crh\/9477679"}},"subtitle":[],"editor":[{"given":"Kalyani","family":"Sen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2026,1]]},"references-count":5,"journal-issue":{"issue":"1","published-print":{"date-parts":[[2026,1]]}},"alternative-id":["10.1155\/crh\/9477679"],"URL":"https:\/\/doi.org\/10.1155\/crh\/9477679","archive":["Portico"],"relation":{},"ISSN":["2090-6560","2090-6579"],"issn-type":[{"value":"2090-6560","type":"print"},{"value":"2090-6579","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1]]},"assertion":[{"value":"2026-04-21","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-08-17","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-09-04","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"9477679"}}