Impact and economic analysis of human T-cell lymphotropic virus type 1 (HTLV-1)-targeted antenatal screening, England and Wales, 2021.

BackgroundHuman T-cell lymphotropic virus type 1 (HTLV-1) is a neglected virus that can cause severe disease and be transmitted from mother to child through breastfeeding. Avoidance of breastfeeding prevents 80% of vertical transmission. The United Kingdom (UK) is currently assessing whether HTLV-1-targeted antenatal screening should be implemented.AimWe aimed to assess the impact and cost-effectiveness of a targeted programme to prevent HTLV-1 vertical transmission in England and Wales.MethodsWe estimated the number of pregnant women who have high risk of HTLV-1 infection based on their or their partner's country of birth. With data from 2021, we used a mathematical model to assess cost-effectiveness of HTLV-1 antenatal screening. We also estimated the annual number of infant infections and the number that could be prevented with screening and intervention.ResultsWe estimate that ca 99,000 pregnant women in England and Wales have high risk of HTLV-1 infection. In the absence of screening, 74 (range: 25-211) HTLV-1 infections in infants would be expected to occur every year in England and Wales. Implementation of targeted screening would prevent 58 (range: 19-164) infant infections annually. The intervention is effective (incremental 0.00333 quality-adjusted life years (QALY)) and cost-saving (GBP -57.56 (EUR -66.85)).ConclusionOur findings support implementation of HTLV-1 targeted antenatal screening to reduce vertical transmission from mothers to infants in the UK.

Period prevalence of uveitis in human T-lymphotropic virus 1 carriers versus noncarriers in a highly endemic area: The Nagasaki Islands Study.

The magnitude of the effect of human T-lymphotropic virus 1 (HTLV-1) infection on uveitis remains unclear. We conducted a cross-sectional study in a highly endemic area of HTLV-1 in Japan. The study included 4265 residents (men, 39.2%), mostly middle-aged and older individuals with a mean age of 69.9 years, who participated in our surveys between April 2016 and September 2022. We identified HTLV-1 carriers by screening using chemiluminescent enzyme immunoassays and confirmatory tests, and the proportion of carriers was 16.1%. Participants with uveitis were determined from the medical records of all hospitals and clinics where certified ophthalmologists practiced. We conducted logistic regression analyses in an age- and sex-adjusted model to compute the odds ratio (OR) and 95% confidence interval (CI) of uveitis according to HTLV-1 infection status. Thirty-two (0.8%) participants had uveitis. For HTLV-1 carriers, the age- and sex-adjusted OR (95% CI) of uveitis was 3.27 (1.57-6.72) compared with noncarriers. In conclusion, HTLV-1 infection was associated with a higher risk of uveitis among mostly middle-aged and older Japanese residents in a highly endemic HTLV-1 area. Our findings suggest that physicians who treat HTLV-1 carriers should assess ocular symptoms, and those who diagnose patients with uveitis should consider HTLV-1 infection.

Inflammatory progressive multifocal leukoencephalopathy with human T-cell lymphotropic virus-1 coinfection.

A middle-aged man with progressive multifocal leukoencephalopathy (PML) in a human T-cell lymphotropic virus type-1 (HTLV-1) carrier on haemodialysis presented with mild dysarthria and ataxia. Brain MRI revealed asymmetric T2-hyperintense lesions in the cerebral white matter, cerebellum and brainstem. A small amount of JC virus (JCV) genome in cerebrospinal fluid was detected by PCR and cerebellar biopsy demonstrated JCV-DNA presence. Pathological findings showed demyelinating lesions and glial cells with mildly enlarged nuclei, accompanied by T-lymphocytes, neutrophils and plasma cell infiltration. The CD4+/CD8+ratio was 0.83. High-dose corticosteroid therapy was effective for inflammatory PML lesions, and the administration of mefloquine combined with mirtazapine led to favourable outcome. The encephalitis in this case is considered to have occurred secondarily to JCV infection in the presence of HTLV-1 infection. Therefore, it is crucial to investigate the presence of HTLV-1 in order to understand the aetiology of this brain inflammation.

Case Report: Disseminated Paracoccidioidomycosis and Strongyloides Hyperinfection in a Patient with Human T-Lymphotropic Virus Type 1/2 Infection.

Co-occurrence of paracoccidioidomycosis and strongyloidiasis in immunosuppressed patients, particularly those infected with human T-lymphotropic virus type 1/2, is infrequent. We describe the case of a Peruvian farmer from the central jungle with human T-lymphotropic virus type 1/2 infection, with 2 months of illness characterized by respiratory and gastrointestinal symptoms associated with fever, weight loss, and enlarged lymph nodes. Strongyloides stercoralis and Paracoccidioides brasiliensis were isolated in sputum and bronchoalveolar lavage samples, respectively. The clinical evolution was favorable after the patient received ivermectin and amphotericin B. We hypothesize that autoinfestation by S. stercoralis in human T-lymphotropic virus type 1/2-infected patients may contribute to the disseminated presentation of Paracoccidioides spp. Understanding epidemiological context is crucial for suspecting opportunistic regional infections, particularly those that may coexist in immunosuppressed patients.

Detecção pré-natal de infecção pelo vírus T-linfotrópico humano (HTLV) 1/2 em gestantes / Prenatal detection of human T-lymphotropic virus (HTLV) 1/2 infection in pregnant women

INTRODUÇÃO: O vírus T-linfotrópico humano HTLV-1 e HTLV-2 são retrovírus com potencial oncogênico, sendo particularmente associados à gênese da leucemia de células T do adulto (ATL). Além disso, estes se relacionam a diversas doenças não-neoplásicas de natureza inflamatória, sendo a mielopatia associada ao HTLV/paraparesia espástica tropical (HAM/TSP) e uveíte pelo HTLV-1 (HU) as mais conhecidas. A infecção pelo HTLV-1/2 tem distribuição mundial, com uma estimativa de até 15 a 20 milhões de pessoas afetadas e, uma vez estabelecida, permanece por toda a vida do indivíduo e na maioria dos casos permanece assintomática, tornando estes indivíduos reservatórios virais. Cerca de 4% dos portadores de HTLV-1 desenvolverão ATL, uma malignidade de células T CD4+ altamente agressiva. Por sua vez, a incapacitante HAM, afeta 2 a 3% das pessoas infectadas. As principais formas de transmissão do HTLV-1e 2 são a relação sexual desprotegida, a transmissão vertical, a amamentação e a exposição direta a sangue ou tecidos infectados. Independentemente da região do mundo, a soroprevalência aumenta com a idade, particularmente nas mulheres, tendo em vista a facilidade da transmissão sexual

Clonality of HIV-1- and HTLV-1-Infected Cells in Naturally Coinfected Individuals.

BACKGROUND: Coinfection with human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus type 1 (HTLV-1) diminishes the value of the CD4+ T-cell count in diagnosing AIDS, and increases the rate of HTLV-1-associated myelopathy. It remains elusive how HIV-1/HTLV-1 coinfection is related to such characteristics. We investigated the mutual effect of HIV-1/HTLV-1 coinfection on their integration sites (ISs) and clonal expansion. METHODS: We extracted DNA from longitudinal peripheral blood samples from 7 HIV-1/HTLV-1 coinfected, and 12 HIV-1 and 13 HTLV-1 monoinfected individuals. Proviral loads (PVL) were quantified using real-time polymerase chain reaction (PCR). Viral ISs and clonality were quantified by ligation-mediated PCR followed by high-throughput sequencing. RESULTS: PVL of both HIV-1 and HTLV-1 in coinfected individuals was significantly higher than that of the respective virus in monoinfected individuals. The degree of oligoclonality of both HIV-1- and HTLV-1-infected cells in coinfected individuals was also greater than in monoinfected subjects. ISs of HIV-1 in cases of coinfection were more frequently located in intergenic regions and transcriptionally silent regions, compared with HIV-1 monoinfected individuals. CONCLUSIONS: HIV-1/HTLV-1 coinfection makes an impact on the distribution of viral ISs and clonality of virus-infected cells and thus may alter the risks of both HTLV-1- and HIV-1-associated disease.

ORP4L is a prerequisite for the induction of T-cell leukemogenesis associated with human T-cell leukemia virus 1.

Human T-cell leukemia virus 1 (HTLV-1) causes adult T-cell leukemia (ATL), but the mechanism underlying its initiation remains elusive. In this study, ORP4L was expressed in ATL cells but not in normal T-cells. ORP4L ablation completely blocked T-cell leukemogenesis induced by the HTLV-1 oncoprotein Tax in mice, whereas engineering ORP4L expression in T-cells resulted in T-cell leukemia in mice, suggesting the oncogenic properties and prerequisite of ORP4L promote the initiation of T-cell leukemogenesis. For molecular insight, we found that loss of miR-31 caused by HTLV-1 induced ORP4L expression in T-cells. ORP4L interacts with PI3Kδ to promote PI(3,4,5)P3 generation, contributing to AKT hyperactivation; NF-κB-dependent, p53 inactivation-induced pro-oncogene expression; and T-cell leukemogenesis. Consistently, ORP4L ablation eliminates human ATL cells in patient-derived xenograft ATL models. These results reveal a plausible mechanism of T-cell deterioration by HTLV-1 that can be therapeutically targeted.

A novel high performing multiplex immunoassay Multi-HTLV for serological confirmation and typing of HTLV infections.

BACKGROUND: Human T-Cell Lymphotropic Viruses (HTLV) type 1 and type 2 account for an estimated 5 to 10 million infections worldwide and are transmitted through breast feeding, sexual contacts and contaminated cellular blood components. HTLV-associated syndromes are considered as neglected diseases for which there are no vaccines or therapies available, making it particularly important to ensure the best possible diagnosis to enable proper counselling of infected persons and avoid secondary transmission. Although high quality antibody screening assays are available, currently available confirmatory tests are costly and have variable performance, with high rates of indeterminate and non-typable results reported in many regions of the world. The objective of this project was to develop and validate a new high-performance multiplex immunoassay for confirmation and discrimination of HTLV-1 and HTLV-2 strains. METHODOLOGY/PRINCIPAL FINDINGS: The multiplex platform was used first as a tool to identify suitable antigens and in a second step for assay development. With data generated on over 400 HTLV-positive blood donors sourced from USA and French blood banks, we developed and validated a high-precision interpretation algorithm. The Multi-HTLV assay demonstrated very high performance for confirmation and strain discrimination with 100% sensitivity, 98.1% specificity and 100% of typing accuracy in validation samples. The assay can be interpreted either visually or automatically with a colorimetric image reader and custom algorithm, providing highly reliable results. CONCLUSIONS/SIGNIFICANCE: The newly developed Multi-HTLV is very competitive with currently used confirmatory assays and reduces considerably the number of indeterminate results. The multiparametric nature of the assay opens new avenues to study specific serological signatures of each patient, follow the evolution of infection, and explore utility for HTLV disease prognosis. Improving HTLV diagnostic testing will be critical to reduce transmission and to improve monitoring of seropositive patients.

A refractory human T-cell leukemia virus type 1-associated myelopathy/tropical spastic paraparesis patient with lymphoma-type adult T-cell leukemia/lymphoma: A case report and review of the literature.

RATIONALE: Adult T-cell leukemia/lymphoma (ATL) and human T-cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) are caused by HTLV-1, but the coexistence of both disorders is rare. The estimated incidence is approximately 3%. PATIENT CONCERNS: A 54-year-old man was unable to stand up because of spastic paraparesis 1 month after the onset. He developed lymphadenopathy in the left supraclavicular fossa 5 months after the onset. The spastic paraplegia and sensory symptoms below the thoracic spinal cord level worsened. DIAGNOSES: Both blood and cerebrospinal fluid (CSF) tests were positive for anti-HTLV-1 antibodies. The patient was diagnosed with rapidly progressive HAM/TSP. He was also diagnosed with lymphoma-type ATL by the biopsy specimen of the lymph node. CSF examination at the time of symptom exacerbation showed abnormal lymphocytes, suggesting central infiltration of the ATL in the central nervous system. INTERVENTIONS: Methylprednisolone pulse therapy and oral prednisolone maintenance therapy were administered for rapidly progressive HAM/TSP. Intrathecal injection of methotrexate was administered for the suggested central infiltration of the ATL. OUTCOMES: Methylprednisolone pulse therapy and intrathecal injection of methotrexate did not improve the patient's exacerbated symptoms. Five months later, clumsiness and mild muscle weakness of the fingers appeared, and magnetic resonance imaging showed swelling of the cervical spinal cord. Clonality analysis showed monoclonal proliferation only in the DNA of a lymph node lesion, but not in the CSF and peripheral blood cells. LESSONS: This was a case of rapidly progressive HAM/TSP associated with lymphoma-type ATL that was refractory to steroids and chemotherapy. The pathogenesis was presumed to involve ATL cells in the brain and spinal cord because of the presence of abnormal lymphocytes in the CSF, but DNA analysis could not prove direct invasion. This case suggests that when we encounter cases with refractory HAM/TSP, it should be needed to suspect the presence of ATL in the background.

The N93D mutation of the human T-cell leukemia virus type 1 envelope glycoprotein found in symptomatic patients enhances neuropilin-1 b1 domain binding.

Human T-cell leukemia virus type 1 (HTLV-1) infection of host cells is mainly mediated by interactions with the viral envelope glycoprotein surface unit (SU) and three host receptors: heparan sulfate proteoglycan, neuropilin-1 (Nrp1), and glucose transporter type 1. Residues 90-94 of SU are considered as a Nrp1 binding site, and our previous results show that an SU peptide consisting of residues 85-94 can bind directly to the Nrp1 b1 domain with a binding affinity of 7.4 µM. Therefore, the SU peptide is expected to be a good model to investigate the SU-Nrp1 interaction. Recently, the N93D mutation in the Nrp1 b1 binding region of the SU was identified in symptomatic patients with HTLV-1 infections in the Brazilian Amazon. However, it remains unclear how the SU-N93D mutation affects Nrp1 b1 binding. To elucidate the impact of the substituted Asp93 of SU on Nrp1 b1 binding, we analyzed the interaction between the SU-N93D peptide and Nrp1 b1 using isothermal titration calorimetry and nuclear magnetic resonance. The SU-N93D peptide binds directly to Nrp1 b1 with a binding affinity of 3.5 µM, which is approximately two-fold stronger than wild-type. This stronger binding is likely a result of the interaction between the substituted residue Asp93 of the N93D peptide and the four residues Trp301, Lys347, Glu348, and Thr349 of Nrp1 b1. Our results suggest that the interaction of SU Asp93 with the four residues of Nrp1 b1 renders the high affinity of the N93D mutant for Nrp1 b1 binding during HTLV-1 entry.

Tumorigenesis and diagnostic practice applied in two oncogenic viruses: Epstein Barr virus and T-cell lymphotropic virus-1-Mini review.

To date, seven viruses have been reliably connected to various forms of human cancer: Epstein Barr Virus (EBV), Kaposi's sarcoma-associated herpesvirus (KSHV), high-risk Human papillomavirus (HPV), Merkel Cell Polyomavirus (MCPV), Hepatitis B virus (HBV), hepatitis C virus (HCV), and Human T-cell leukemia virus type 1 (HTLV1). This mini-review summarizes two of these viruses, EPV and HTLV-1, in terms of their general pathway of infection, the key mechanism of cancer induction, and the prominent technologies used to detect the infections. EBV is the first discovered human oncovirus and HTLV - I is the first human retrovirus and both were discovered from patient with distinct lymphoma clinical condition. Both the viruses can immortalize lymphocytes invitro and lymphomas are common manifestation of majority oncogenic viruses. Lymphomagenesis are discovered in associated with EBV, HTLV-I, Human Immunodeficiency virus (HIV), Kaposi sarcoma - associated herpes virus and hepatitis c virus. Later the undefined mechanism behind the induction of cancer by these viruses was unveiled gradually along with the responsible cofactors and mimicry mechanism. These two viruses contrast in their genetic structure, location of the infection, and latency, yet clinically, they generate similar cancer disorders. The major focus of this study is to brief the mechanism of these two unrelated viral cancer promoting agents on how they simulate a condition similar to lymphoma which may or may not undergo mimicry and cofactor utilization process, handpicked and vital genes behind the transformation mechanism are given accordingly.

Quantification of T cell clonality in human T cell leukaemia virus type-1 carriers can detect the development of adult T cell leukaemia early.

Adult T cell leukaemia/lymphoma (ATL) arises from clonally expanded T cells that are infected with human T cell leukaemia virus type-1 (HTLV-1). Here, we show that ATL can be detected early in HTLV-1-carriers through quantification of T-cell receptor (TCR)Vß subunit diversity on T-cells infected with HTLV-1 (CD3+ CCR4+ CD26- T-cells) using an 'oligoclonality index' (OCI-flow). We established a reference range for OCI-flow by analysing peripheral blood mononuclear cells (PBMCs) from HTLV-1-carriers who had not developed ATL in a median of 10.5 years follow up (n = 38) and patients with ATL (n = 30). In the third cohort of HTLV-1-carriers with no history or clinical evidence of ATL (n = 106), 19% of high proviral load (PVL, ≥4 copies of HTLV-1/100 PBMCs) carriers had an OCI-flow in the ATL range, >0.770. Carriers with an OCI-flow >0.770 (n = 14) had higher lymphocyte counts and PVLs and were more likely to have a family history of ATL than carriers with OCI-flow ≤0.770. ATL subsequently developed in two of these 14 carriers but no carriers with OCI-flow ≤0.770 (p = 0.03, cumulative follow-up 129 person-years). This method can be used to identify a subset of high-PVL HTLV-1-carriers at increased risk of developing ATL who may benefit from intervention therapy, prior to the detection of disease.

Genome wide association study of HTLV-1-associated myelopathy/tropical spastic paraparesis in the Japanese population.

HTLV-1-associated myelopathy (HAM/TSP) is a chronic and progressive inflammatory disease of the central nervous system. The aim of our study was to identify genetic determinants related to the onset of HAM/TSP in the Japanese population. We conducted a genome-wide association study comprising 753 HAM/TSP patients and 899 asymptomatic HTLV-1 carriers. We also performed comprehensive genotyping of HLA-A, -B, -C, -DPB1, -DQB1, and -DRB1 genes using next-generation sequencing technology for 651 HAM/TSP patients and 804 carriers. A strong association was observed in HLA class I (P = 1.54 × 10-9) and class II (P = 1.21 × 10-8) loci with HAM/TSP. Association analysis using HLA genotyping results showed that HLA-C*07:02 (P = 2.61 × 10-5), HLA-B*07:02 (P = 4.97 × 10-10), HLA-DRB1*01:01 (P = 1.15 × 10-9) and HLA-DQB1*05:01 (P = 2.30 × 10-9) were associated with disease risk, while HLA-B*40:06 (P = 3.03 × 10-5), HLA-DRB1*15:01 (P = 1.06 × 10-5) and HLA-DQB1*06:02 (P = 1.78 × 10-6) worked protectively. Logistic regression analysis identified amino acid position 7 in the G-BETA domain of HLA-DRB1 as strongly associated with HAM/TSP (P = 9.52 × 10-10); individuals homozygous for leucine had an associated increased risk of HAM/TSP (odds ratio, 9.57), and proline was protective (odds ratio, 0.65). Both associations were independent of the known risk associated with proviral load. DRB1-GB-7-Leu was not significantly associated with proviral load. We have identified DRB1-GB-7-Leu as a genetic risk factor for HAM/TSP development independent of proviral load. This suggests that the amino acid residue may serve as a specific marker to identify the risk of HAM/TSP even without knowledge of proviral load. In light of its allele frequency worldwide, this biomarker will likely prove useful in HTLV-1 endemic areas across the globe.

Low Annexin A1 level in HTLV-1 infected patients is a potential biomarker for the clinical progression and diagnosis of HAM/TSP.

BACKGROUND: Human T-lymphotropic virus 1 (HTLV-1) is etiologically associated with the chronic inflammatory neurodegenerative disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) Annexin A1 (AnxA1) is an anti-inflammatory protein with proposed neuroprotective and anti-neuroinflammatory functions. We hypothesized that ANXA1 gene expression may be dysregulated in HTLV-1-infected HAM/TSP patients. METHODS: This study involved 37 individuals infected with HTLV-1, including 21 asymptomatic (AS) carriers and 16 with HAM/TSP, and a control group of 30 individuals negative for HTLV-1 and HTLV-2. For AS HTLV-1-positive and HAM/TSP patients, ANXA1 and formyl peptide receptor (FPR1, FPR2 and FPR3) expression and HTLV-1 proviral load (PVL) in peripheral blood cells were evaluated by real-time quantitative PCR (qPCR), and plasma AnxA1 levels were determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: ANXA1 gene expression was increased in the AS group compared with the HAM/TSP and control groups, but the differences were not statistically significant. FPR1 gene expression was higher in patients with HTLV-1 than in controls (AS, p = 0.0032; HAM/TSP, p < 0.0001). Plasma AnxA1 levels were higher in the AS group than in the HAM/TSP group (p = 0.0045), and PVL was higher in patients with HAM/TSP than in AS individuals (p = 0.0162). The use of a combined ROC curve using Annexin 1 levels and proviral load significantly increased the sensitivity and specificity to predict progression to HAM/TSP (AUC = 0.851 and AUC = 0.937, respectively, to AUC = 1000). CONCLUSIONS: Our results suggest that AnxA1 may be dysregulated in HAM/TSP patients. Serological detection of AnxA1 in association with proviral load may provide a prognostic biomarker for HTLV-1-associated neurodegenerative disease.

Human T-Lymphotropic virus type 1 infection in absence of tax gene: A challenge for molecular diagnosis.

This is the first report of HTLV-1 infection without detectable tax gene. Even though the tax gene of HTLV-1 presents high genetic stability, in the case presented here no sequence of tax was detected by three different and widely used molecular assays targeting several sequences of the gene. Nevertheless, HTLV-1 pol and env genes and LTR region were properly detectable. Several PCRs targeting tax sequences have been developed and largely used for molecular diagnosis of HTLV infection since the tax gene of HTLV-1 is known to be well preserved and intolerant to changes or mutations. In the case reported here, molecular detection of the virus was challenging. HTLV prevalence is complex and in many regions remains unknown. The identification of HTLV-infected individuals is important to determine its actual prevalence and design strategies to reduce viral spread. The finding and communication of HTLV-1 defective-provirus strains is important and necessary to guide the selection of representative target sequences on HTLV genome to design molecular assays, highlighting that different sequences should be combined to ensure adequate diagnosis. The latter is especially relevant in cases when discordant results between serological and molecular assays. This report contributes to the knowledge of the overall molecular epidemiology of HTLV-1 and encourages the need of surveillance of HTLV-1 "missed tax gene profiles" and the evaluation of the impact of these defective viral variants on molecular diagnosis and human health.

Genetic profile of adult T-cell leukemia/lymphoma in Okinawa: Association with prognosis, ethnicity, and HTLV-1 strains.

Genetic alterations in adult T-cell leukemia/lymphoma (ATLL), a T-cell malignancy associated with HTLV-1, and their clinical impacts, especially from the perspective of viral strains, are not fully elucidated. We employed targeted next-generation sequencing and single nucleotide polymorphism array for 89 patients with ATLL in Okinawa, the southernmost islands in Japan, where the frequency of HTLV-1 tax subgroup-A (HTLV-1-taxA) is notably higher than that in mainland Japan, where most ATLL cases have HTLV-1-taxB, and compared the results with previously reported genomic landscapes of ATLL in mainland Japan and the USA. Okinawan patients exhibited similar mutation profiles to mainland Japanese patients, with frequent alterations in TCR/NF-ĸB (eg, PRKCB, PLCG1, and CARD11) and T-cell trafficking pathways (CCR4 and CCR7), in contrast with North American patients who exhibited a predominance of epigenome-associated gene mutations. Some mutations, especially GATA3 and RHOA, were detected more frequently in Okinawan patients than in mainland Japanese patients. Compared to HTLV-1-taxB, HTLV-1-taxA was significantly dominant in Okinawan patients with these mutations (GATA3, 34.1% vs 14.6%, P = .044; RHOA, 24.4% vs 6.3%, P = .032), suggesting the contribution of viral strains to these mutation frequencies. From a clinical viewpoint, we identified a significant negative impact of biallelic inactivation of PRDM1 (P = .027) in addition to the previously reported PRKCB mutations, indicating the importance of integrated genetic analysis. This study suggests that heterogeneous genetic abnormalities in ATLL depend on the viral strain as well as on the ethnic background. This warrants the need to develop therapeutic interventions considering regional characteristics.

Allogeneic hematopoietic stem cell transplantation for adult T-cell leukemia/lymphoma with HTLV-1-associated myelopathy.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) can be curative for adult T-cell leukemia/lymphoma (ATL), but comorbidities increase transplant-related mortality. Here we report the outcome of allo-HSCT in a patient with ATL with human T-cell leukemia virus type I (HTLV-1)-associated myelopathy-tropical spastic paraparesis (HAM/TSP). A 48-year-old man was diagnosed with HAM/TSP and started prednisolone therapy. Ten years later, he developed lymphoma-type ATL. At the diagnosis of ATL, Osame's Motor Disability Score (OMDS) was 4. When prednisolone was gradually tapered and stopped following chemotherapy for ATL, HAM/TSP symptoms recurred (OMDS 7). Bone marrow transplantation from a human leukocyte antigen allele 8/8 matched unrelated donor was performed while ATL was in partial remission. Neutrophil engraftment with complete donor chimerism was achieved on day 19 after allo-HSCT. Mild gait improvement (OMDS 5) was observed on day 30. Although ATL relapsed on day 275, progression of HAM/TSP symptoms was not observed. Furthermore, there was no clear progression of HAM/TSP symptoms after donor lymphocyte infusions. The outcome of this case suggests that ATL patients with HAM/TSP tolerate allo-HSCT and donor lymphocyte infusions.