doi:10.1016/j.jcv.2023.105578engde Mendoza, CarmenRando, AriadnaMiró, ElisendaPena, María JoséRodríguez-Avial, IciarOrtega, DiegoGonzález-Praetorius, AlejandroReina, GabrielPintos, IlduaraPozuelo, María JoséSoriano, VicenteCalderón, E.Rodríguez-Iglesias, M.Montiel, N.Trujillo, T.Viciana, I.Cabezas, T.Lozano, A.Fernández-Fuertes, E.Fernández, J.M.García, F.Benito, R.Algarate, S.Ducons, M.Roc, L.Cifuentes, C.Fernández-Baca, V.Fernández-Montero, J.VMaciá, MD.Hernández-Betancor, A.Martín, A.M.Hernández, M.López-Lirola, A.M.Gómez-Sirvent, J.L.Copado, R.Cano, M.E.Rojo, S.Eirós, J.M.Rodríguez, M.Gómez-Hernando, C.Force, L.Cebollero, A.Delgado, J.F.Rodríguez, G.Fernández-Pereira, L.Aguilera, A.Pereira, S.García, J.Trigo, M.Diz, J.García-Campello, M.Cortizo, S.Pérez, S.Morano, L.Arazamendi, M.Salicio, Y.Ugalde, E.Nieto, M.C.Liendo, P.Goikoetxea, A.J.Ocete, M.D.Ramos, J.M.Escribano, I.Sauleda, S.Pirón, M.González, R.Richart, A.Barea, L.Jiménez, A.Blanco, L.Navarro, L.Ayerdi, O.Baza, B.Rodriguez, C.del Romero, J.Galar, A.Aldamiz, T.Valeiro, M.Pérez, L.Martín-Carbonero, L.Fernández-Ruiz, M.Parra, P.Redondo, N.Ruiz-Merlo, T.Barreiro, P.Treviño, A.Corral, O.Moreno-Torres, V.Carrizo, P.Huertas, A.Vargas-Núñez, J.A.Adult T-cell leukemia/lymphoma in HTLV-1 non-endemic regionsART-2023-137162Background HTLV-1 infection is a neglected disease, despite producing neurological and lymphoproliferative severe illnesses and affect over 10 million people worldwide. Roughly 5% of HTLV-1 carriers develop Adult T-cell leukemia/lymphoma (ATLL), one of the most aggressive hematological malignancies. Methods A national HTLV-1 register exists since 1989 in Spain, a non-endemic country with a large migrant flow from Latin America and Equatorial Africa, where HTLV-1 is endemic. The main features of all patients diagnosed with ATLL in Spain up to date are reported. Results A total of 451 cases of HTLV-1 infection had been reported in Spain until the end of year 2022. ATLL had been diagnosed in 35 (7.8%). The current average incidence of ATLL in Spain is of two cases per year. Women represent 57% of ATLL patients. Mean age at diagnosis was 47 years-old. Roughly 57% were Latin Americans and 26% Africans. At diagnosis, the majority presented with acute or lymphoma clinical forms. Survival was shorter than one year in most of them. Mean HTLV-1 proviral load was significantly greater in ATLL patients than in asymptomatic HTLV-1 carriers (2,305 vs 104 copies/104 PBMC). HTLV-1 subtyping in 6 ATLL patients found the 1a transcontinental variant (n = 4) and the Japanese variant (n = 2). All ATLL patients were negative for HIV-1, did not develop HTLV-1-associated myelopathy and were not transplant recipients. Conclusion The rate of ATLL is very low in Spain and mostly associated to migrants from HTLV-1 endemic regions. Given the poor clinical outcome of ATLL, HTLV-1 testing should be performed at least once in all migrants coming from HTLV-1 endemic countries and in natives who have lived in or had sex partners from such regions.2023http://zaguan.unizar.es/record/13169710.1016/j.jcv.2023.105578http://zaguan.unizar.es/record/131697oai:zaguan.unizar.es:131697info:eu-repo/grantAgreement/ES/ISCIII/FIS/PI21-1717JOURNAL OF CLINICAL VIROLOGY 167 (2023), 105578 [5 pp.]All rights reservedhttp://www.europeana.eu/rights/rr-f/info:eu-repo/semantics/closedAccess