Molecular and Phylogenetic Characterization of HTLV-1 Infection in Patients With Hematological Malignancies in the State of Para, Northern Brazil

by | Jul 9, 2026 | Publications

J Med Virol. 2026 Jul;98(7):e71024. doi: 10.1002/jmv.71024.

ABSTRACT

Human T-lymphotropic viruses 1 and 2 (HTLV-1 and HTLV-2) were first isolated from patients with hematological malignancies. This study was the first to investigate the frequency of HTLV-1 and its molecular diversity among patients with hematolymphoid cancers who were treated at a leading reference hospital in Pará, northern Brazil. For this purpose, information from the International Classification of Diseases (ICD), laboratory test records, and peripheral blood samples were obtained. Patients with confirmed diagnosis of leukemia/lymphoma, myeloma, other hematological malignancies, and those under diagnostic investigation were included in the study. Serological screening for anti-HTLV-1/2 antibodies was carried out by ELISA, and infection was confirmed by real-time PCR. PCR-positive samples were sequenced for phylogenetic analysis. Of 329 people assessed, 47.7% were men (157) and 52.3% were women (172). The overall prevalence of HTLV-1 was 1.82% (6/329), with 2.5% (n = 4) in men and 1.2% (n = 2) in women. Phylogenetic analysis of the 5’LTR region (715 bp) of HTLV-1 indicated that the isolates belonged to the Cosmopolitan subtype, Transcontinental subgroup. Positivity among patients with lymphoma was 6.56% (4/61), with one patient diagnosed with Hodgkin lymphoma. Among patients under clinical investigation and with other types of cancer, the prevalence of infection was 1.19% (1/84) and 2.38% (1/42), respectively. A decrease in red blood cell count, hemoglobin, and hematocrit was identified in cancer patients with a negative HTLV diagnosis compared to HTLV-positive patients. Our results highlight the importance of including HTLV-1/2 testing in the routine follow-up of cancer patients, for the sake of existing successful treatment protocols.

PMID:42423354 | DOI:10.1002/jmv.71024

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