The importance of the clinical classification of adult T-cell leukemia/lymphoma (ATLL) in the prognosis.

BACKGROUND: Adult T-cell leukemia/lymphoma (ATLL), a peripheral T-cell leukemia/lymphoma associated with the human T-cell lymphotropic virus type-1 (HTLV-1), has been classified following the clinical forms defined by Shimoyama in 1991. A suggestion to modify Shimoyama's classification was proposed in 2007 to differentiate within the smoldering patients those who presented nodules or tumors in the skin without lung involvement, which was named the primary cutaneous tumoral (PCT) form of ATLL. In the present study, according to their clinicopathological characteristics, we estimated the mortality rates of 143 ATLL patients from Bahia, Brazil. We also evaluated the importance of classifying PCT/ATLL separately from the smoldering type on disease prognosis. METHODOLOGY/PRINCIPAL FINDINGS: Diagnosis of ATLL was established based on a positive serology for HTLV-1, histopathological and/or cytological diagnosis of peripheral T-cell leukemia/lymphoma. Patients were clinically grouped according to Shimoyama's classification, considering PCT variants separately from the smoldering cases. Bivariate and multivariable survival analyses were applied to identify factors associated with disease prognosis. Significant differences in the median survival time were observed between the clinical types, with the smoldering type presenting the longest median survival (109 months) compared to the other forms (<50 months); the median survival for PCT/ATLL was 20 months. Multivariable analysis confirmed that ATLL clinical types were associated with survival, with a better prognosis for patients with the smoldering and chronic types. Furthermore, skin involvement was related to a worse outcome in the multivariable analysis, regardless of the clinical form and presence of lymphadenopathy. CONCLUSIONS/SIGNIFICANCE: Our results reinforce the importance of considering the PCT/ATLL separately from the smoldering type when classifying ATLL to better define prognosis and treatment, given the significant difference in the survival of patients between the smoldering form and PCT/ATLL. Skin involvement should also be considered an independent prognostic factor in patients with ATLL.

Progression of Infective Dermatitis Associated with HTLV-1 to Adult T-Cell Leukemia/Lymphoma-Case Report and Literature Review.

ABSTRACT: The human T-cell lymphotropic virus type 1 is a retrovirus that may cause severe diseases such as infective dermatitis associated with HTLV-1 (IDH) and adult T-cell leukemia/lymphoma (ATL). IDH is a chronic relapsing infected eczema of childhood, and ATL is a distinct type of peripheral T-cell leukemia/lymphoma, which is classified into the following types: smoldering, primary cutaneous tumoral, chronic, lymphoma, and acute. Progression of IDH to ATL during the course of IDH has been previously reported in 3 young patients, two of them from Bahia (Brazil). We present the case of a 22-year-old man who had IDH since childhood and developed ATL 18 months ago. The lymphoma lesions were superimposed on previously existing IDH lesions (forehead, axillae, umbilical area, and neck) or in areas generally affected by IDH (external genitalia, hypogastrium, groin, and eyelid). Cutaneous lesions in ATL are very frequent, but in this patient, besides infiltrated plaques and papules presented vesicles on the skin corresponding histologically to dilated Pautrier abscesses. Vesicular ATL is a rare condition. This case constitutes a very demonstrative example of the close correlation between IDH and ATL.

Germinal epimutation of Fragile Histidine Triad (FHIT) gene is associated with progression to acute and chronic adult T-cell leukemia diseases.

BACKGROUND: Human T cell Leukemia virus type 1 (HTLV-I) is etiologically linked to adult T cell leukemia/lymphoma (ATL) and an inflammatory neurodegenerative disease called HTLV-I-associated myelopathy or tropical spastic paraparesis (HAM/TSP). The exact genetic or epigenetic events and/or environmental factors that influence the development of ATL, or HAM/TSP diseases are largely unknown. The tumor suppressor gene, Fragile Histidine Triad Diadenosine Triphosphatase (FHIT), is frequently lost in cancer through epigenetic modifications and/or deletion. FHIT is a tumor suppressor acting as genome caretaker by regulating cellular DNA repair. Indeed, FHIT loss leads to replicative stress and accumulation of double DNA strand breaks. Therefore, loss of FHIT expression plays a key role in cellular transformation. METHODS: Here, we studied over 400 samples from HTLV-I-infected individuals with ATL, TSP/HAM, or asymptomatic carriers (AC) for FHIT loss and expression. We examined the epigenetic status of FHIT through methylation specific PCR and bisulfite sequencing; and correlated these results to FHIT expression in patient samples. RESULTS: We found that epigenetic alteration of FHIT is specifically found in chronic and acute ATL but is absent in asymptomatic HTLV-I carriers and TSP/HAM patients' samples. Furthermore, the extent of FHIT methylation in ATL patients was quantitatively comparable in virus-infected and virus non-infected cells. We also found that longitudinal HTLV-I carriers that progressed to smoldering ATL and descendants of ATL patients harbor FHIT methylation. CONCLUSIONS: These results suggest that germinal epigenetic mutation of FHIT represents a preexisting mark predisposing to the development of ATL diseases. These findings have important clinical implications as patients with acute ATL are rarely cured. Our study suggests an alternative strategy to the current "wait and see approach" in that early screening of HTLV-I-infected individuals for germinal epimutation of FHIT and early treatment may offer significant clinical benefits.

Clinicopathological aspects and proviral load of adulthood infective dermatitis associated with HTLV-1: Comparison between juvenile and adulthood forms.

BACKGROUND: Infective dermatitis associated with human T-cell lymphotropic virus type-1 (HTLV-1), (IDH), is a chronic eczema occurring in HTLV-1 infected children. Rare cases of adulthood IDH have been reported and no study until now aimed to compare juvenile and adulthood IDH. METHODOLOGY/PRINCIPAL FINDINGS: Twelve cases of adulthood IDH followed for a mean time of 7.5 years were analyzed according to clinicopathological and molecular aspects, comparing them to juvenile IDH cases. Diagnosis was based on the modified major criteria used for juvenile IDH. Proviral load (PVL) assessment was performed by real-time PCR technique. Adulthood IDH presented similar clinicopathological and molecular aspects compared to juvenile IDH. The morphology of lesions and areas of involvement were similar, except for the involvement of the ankles and inframammary folds in the adulthood form. HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) occurred in six adulthood IDH patients, with almost equal frequency. However, at least in two patients, HAM/TSP appeared prior to IDH, differently from what was observed in juvenile IDH. CONCLUSIONS/SIGNIFICANCE: Adulthood IDH is similar to juvenile IDH according to clinicopathological aspects and PVL levels. Therefore, the same modified major diagnostic criteria for juvenile IDH can be applied to both forms.

Complete genome sequence of human T-cell lymphotropic type 1 from patients with different clinical profiles, including infective dermatitis.

The HTLV-1 is the first human retrovirus and is associated with several clinical syndromes, however, the pathogenesis of these clinical manifestations is still not fully understood. Furthermore, there are few complete genomes publicly available, about 0.12 complete genomes per 10,000 infected individuals and the databases have a major deficiency of sequences information. This study generated and characterized 31 HTLV-1 complete genomes sequences derived from individuals with Tropical Spastic Paraparesis/HTLV-1-Associated Myelopathy (TSP/HAM), Adult T-cell leukemia/lymphoma (ATL), infective dermatitis associated to HTLV-1 (IDH) and asymptomatic patients. These sequences are associated to clinical and epidemiological information about the patients. The sequencing data generated on Ion Torrent PGM platform were assembled and mapped against the reference HTLV-1 genome. These sequences were genotyped as Cosmopolitan subtype, Transcontinental subgroup. We identified the variants in the coding regions of the genome of the different clinical profiles, however, no statistical relation was detected. This study contributed to increase of HTLV-1 complete genomes in the world. Furthermore, to better investigate the contribution of HTLV-1 mutations for the disease outcome it is necessary to evaluate the interaction of the viral genome and characteristics of the human host.

HTLV-1 proviral load in infective dermatitis associated with HTLV-1 does not increase after the development of HTLV-1-associated myelopathy/tropical spastic paraparesis and does not decrease after IDH remission.

INTRODUCTION: Infective dermatitis associated with HTLV-1 (IDH) is a recurrent eczema which affects children vertically infected with HTLV-1. In Bahia, Brazil, we recently reported that 47% of IDH patients also develop juvenile HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a progressive disabling disorder which is typically reported in adult HTLV-1 carriers. IDH may also predispose to adult T-cell leukemia/lymphoma, a neoplasm associated with HTLV-1. The factors relating to the development of HTLV-1-associated juvenile diseases have not yet been defined. HTLV-1 proviral load (PVL) is one of the main parameters related to the development of HTLV-1 associated diseases in adults. In the current study, we investigated the role of PVL in IDH and juvenile HAM/TSP. METHODOLOGY/PRINCIPAL FINDINGS: This is a cohort study that included fifty-nine HTLV-1 infected children and adolescents, comprising 16 asymptomatic carriers, 18 IDH patients, 20 patients with IDH and HAM/TSP (IDH/HAM/TSP) and five with HAM/TSP. These patients were followed-up for up to 14 years (median of 8 years). We found that PVL in IDH and IDH/HAM/TSP patients were similarly higher than PVL in juvenile asymptomatic carriers (p<0.0001). In those IDH patients who developed HAM/TSP during follow-up, PVL levels did not vary significantly. HAM/TSP development did not occur in those IDH patients who presented high levels of PVL. IDH remission was associated with an increase of PVL. Inter-individual differences in PVL were observed within all groups. However, intra-individual PVL did not fluctuate significantly during follow-up. CONCLUSIONS/SIGNIFICANCE: High PVL in IDH patients was not necessary indicative of progression to HAM/TSP. PVL did not decrease after IDH remission. The maintenance of high PVL after remission could favor early development of ATL. Therefore, IDH patients would have to be followed-up even after remission of IDH and for a long period of time.

Assessment of Genetic Diversity of HTLV-1 ORF-I Sequences Collected from Patients with Different Clinical Profiles.

The human T cell lymphotropic virus type 1 (HTLV-1) infects 5 to 10 million individuals and remains without specific treatment. This retrovirus genome is composed of the genes gag, pol, env, and a region known as pX. This region contains four open reading frames (ORFs) that encode specific proteins. The ORF-I produces the protein p12 and its cleavage product, p8. In this study, we analyzed the genetic diversity of 32 ORF-I sequences from patients with different clinical profiles. Seven amino acid changes with frequency over 5% were identified: G29S, P34L, L55F, F61L, S63P, F78L, and S91P. The identification of regions where the posttranslational sites were identified showed a high identity among the sequences and the amino acid changes exclusive of specific clinical profile were found in less than 5% of the samples. We compare the findings with 2.406 sequences available in GenBank. The low overall genetic diversity found suggested that this region could be used in the HTLV-1 vaccine development.

Revised Adult T-Cell Leukemia-Lymphoma International Consensus Meeting Report.

PURPOSE: Adult T-cell leukemia-lymphoma (ATL) is a distinct mature T-cell malignancy caused by chronic infection with human T-lymphotropic virus type 1 with diverse clinical features and prognosis. ATL remains a challenging disease as a result of its diverse clinical features, multidrug resistance of malignant cells, frequent large tumor burden, hypercalcemia, and/or frequent opportunistic infection. In 2009, we published a consensus report to define prognostic factors, clinical subclassifications, treatment strategies, and response criteria. The 2009 consensus report has become the standard reference for clinical trials in ATL and a guide for clinical management. Since the last consensus there has been progress in the understanding of the molecular pathophysiology of ATL and risk-adapted treatment approaches. METHODS: Reflecting these advances, ATL researchers and clinicians joined together at the 18th International Conference on Human Retrovirology-Human T-Lymphotropic Virus and Related Retroviruses-in Tokyo, Japan, March, 2017, to review evidence for current clinical practice and to update the consensus with a new focus on the subtype classification of cutaneous ATL, CNS lesions in aggressive ATL, management of elderly or transplantation-ineligible patients, and treatment strategies that incorporate up-front allogeneic hematopoietic stem-cell transplantation and novel agents. RESULTS: As a result of lower-quality clinical evidence, a best practice approach was adopted and consensus statements agreed on by coauthors (> 90% agreement). CONCLUSION: This expert consensus highlights the need for additional clinical trials to develop novel standard therapies for the treatment of ATL.

Decreased RORC expression and downstream signaling in HTLV-1-associated adult T-cell lymphoma/leukemia uncovers an antiproliferative IL17 link: A potential target for immunotherapy?

Retinoic acid-related drugs have shown promising pre-clinical activity in Adult T-cell Leukemia/Lymphoma, but RORC signaling has not been explored. Therefore, we investigated transcriptome-wide interactions of the RORC pathway in HTLV-1 and ATL, using our own and publicly available gene expression data for ATL and other leukemias. Gene expression data from ATL patients were analyzed using WGCNA to determine gene modules and their correlation to clinical and molecular data. Both PBMCs and CD4+ T-Cells exhibited decreased RORC expression in four different ATL cohorts. A small subset of RORChi ATL patients was identified with significantly lower pathognomonic CADM1 and HBZ levels but similar levels of other ATL markers (CD4/CD25/CCR4), hinting at a less aggressive ATL subtype. An age-dependent decrease in RORC expression was found in HTLV-1-infected individuals, but not in healthy controls, suggesting an early molecular event predisposing to leukemogenesis. Genes upstream of RORC signaling were members of a proliferative gene module (containing proliferation markers PCNA/Ki67), whereas downstream members clustered in an anti-proliferative gene module. IL17C transcripts showed the strongest negative correlation to PCNA in both ATL cohorts, which was replicated in two large cohorts of T- and B-cell acute lymphoid leukemia (ALL). Finally, IL17C expression in purified CD4 + CCR4 + CD26-CD7- "ATL-like" cells from HTLV-1-infected individuals and ATL patients was negatively correlated with clonality, underscoring a possible antileukemic/antiproliferative role. In conclusion, decreased RORC expression and downstream signaling might represent an early event in ATL pathogenesis. An antiproliferative IL17C/PCNA link is shared between ATL, T-ALL and B-ALL, suggesting (immuno)therapeutic benefit of boosting RORC/IL17 signaling.

Early Juvenile Human T-cell Lymphotropic Virus Type-1-Associated Myelopathy/Tropical Spastic Paraparesis: Study of 25 Patients.

Background: Human T-cell lymphotropic virus type-1 (HTLV-1) may cause severe diseases such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and infective dermatitis associated with HTLV-1 (IDH). The clinical characteristics and progression of 25 early onset HAM/TSP associated or not to IDH were described. Methods: Following-up 37 IDH patients with neurological examinations, 54% developed HAM/TSP. To these cases were added 5 cases of juvenile HAM/TSP. The patients were HTLV-1+ and were submitted to dermatological and neurological examinations. Diagnosis of HAM/TSP was performed according to Osame et al (1990) and Castro-Costa et al (2006) criteria. Results: Twenty-one patients were classified as definite HAM/TSP by both criteria, 3 as probable HAM/TSP by Osame et al, and another as probable HAM/TSP according to Castro-Costa et al Median age at onset of neurological manifestations was 9 years for the IDH/HAM/TSP group and 16 years for the HAM/TSP group (P = .045). In 12 patients, the onset of neurological manifestations occurred when they were less than 10 years of age. In the group IDH/HAM/TSP, the neurological symptoms always begun during the period of activity of IDH. The progression of HAM/TSP evaluated in 17 cases was heterogeneous, and 3 had rapid progressive course. Conclusions: The juvenile HAM/TSP may occur very early and also presents marked female predominance. Progression of IDH to HAM/TSP before 19 years of age is frequent (54%). Rapid progressive form may also occur in early HAM/TSP. As juvenile IDH and HAM/TSP are due to vertical transmission through breastfeeding, it is very important to avoid this pathway of infection.

A genetic IFN/STAT1/FAS axis determines CD4 T stem cell memory levels and apoptosis in healthy controls and Adult T-cell Leukemia patients.

Adult T-cell leukemia (ATL) is an aggressive, chemotherapy-resistant CD4+CD25+ leukemia caused by HTLV-1 infection, which usually develops in a minority of patients several decades after infection. IFN + AZT combination therapy has shown clinical benefit in ATL, although its mechanism of action remains unclear. We have previously shown that an IFN-responsive FAS promoter polymorphism in a STAT1 binding site (rs1800682) is associated to ATL susceptibility and survival. Recently, CD4 T stem cell memory (TSCM) Fashi cells have been identified as the hierarchical cellular apex of ATL, but a possible link between FAS, apoptosis, proliferation and IFN response in ATL has not been studied. In this study, we found significant ex vivo antiproliferative, antiviral and immunomodulatory effects of IFN-α treatment in short-term culture of primary mononuclear cells from ATL patients (n = 25). Bayesian Network analysis allowed us to integrate ex vivo IFN-α response with clinical, genetic and immunological data from ATL patients, thereby revealing a central role for FAS -670 polymorphism and apoptosis in the coordinated mechanism of action of IFN-α. FAS genotype-dependence of IFN-induced apoptosis was experimentally validated in an independent cohort of healthy controls (n = 20). The same FAS -670 polymorphism also determined CD4 TSCM levels in a genome-wide twin study (p = 7 × 10-11, n = 460), confirming a genetic link between apoptosis and TSCM levels. Transcriptomic analysis and cell type deconvolution confirmed the FAS genotype/TSCM link and IFN-α-induced downregulation of CD4 TSCM-specific genes in ATL patient cells. In conclusion, ex vivo IFN-α treatment exerts a pleiotropic effect on primary ATL cells, with a genetic IFN/STAT1/Fas axis determining apoptosis vs. proliferation and underscoring the CD4 TSCM model of ATL leukemogenesis.

Early Onset of HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) and Adult T-cell Leukemia/Lymphoma (ATL): Systematic Search and Review.

Human T-cell lymphotropic virus type 1 (HTLV-1) is endemic in some regions and its vertical transmission occurs mainly through breastfeeding. About 10% of carriers develop associated diseases including HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), adult T-cell leukemia/lymphoma (ATL) and infectious dermatitis associated with HTLV-1 (IDH). We searched for available case reports of early-onset HAM/TSP and ATL to evaluate demographic and disease aspects in infantile-juvenile patients. In the reviewed literature, 27 HAM/TSP and 31 ATL cases were found. In almost all of them, the most likely route of transmission was through breastfeeding. ATL is rarely reported, notwithstanding it may be underestimated because T-cell lymphomas are not investigated for HTLV-1 infection in this age group. IDH was frequently associated with HAM/TSP. The investigation of HTLV-1 infection in pregnant women is an important matter of public health and should be mandatory in endemic countries.

Decreased RORC expression and downstream signaling in HTLV-1-associated Adult T-cell Lymphoma/Leukemia uncovers an antiproliferative IL17 link: a potential target for immunotherapy?

Retinoic acid-related drugs have shown promising pre-clinical activity in Adult T-cell Leukemia/Lymphoma, but RORC signaling has not been explored. Therefore, we investigated transcriptome-wide interactions of the RORC pathway in HTLV-1 and ATL, using our own and publicly available gene expression data for ATL and other leukemias. Gene expression data from ATL patients were analyzed using WGCNA to determine gene modules and their correlation to clinical and molecular data. Both PBMCs and CD4+ T-cells showed decreased RORC expression in four different ATL cohorts. A small subset of RORChi ATL patients was identified with significantly lower pathognomonic CADM1 and HBZ levels but similar levels of other ATL markers (CD4/CD25/CCR4), hinting at a less aggressive ATL subtype. An age-dependent decrease in RORC expression was found in HTLV-1-infected individuals, but not in healthy controls, suggesting an early molecular event predisposing to leukemogenesis. Genes upstream of RORC signaling were members of a proliferative gene module (containing proliferation markers PCNA/Ki67), whereas downstream members clustered in an anti-proliferative gene module. IL17C transcripts showed the strongest negative correlation to PCNA in both ATL cohorts, which was replicated in two large cohorts of T- and B-cell acute lymphoid leukemia (ALL). Finally, IL17C expression in purified CD4+CCR4+CD26-CD7- "ATL-like? cells from HTLV-1-infected individuals and ATL patients was negatively correlated with clonality, underscoring a possible antileukemic/antiproliferative role. In conclusion, decreased RORC expression and downstream signaling might represent an early event in ATL pathogenesis. An antiproliferative IL17C/PCNA link is shared between ATL, T-ALL and B-ALL, suggesting (immuno)therapeutic benefit of boosting RORC/IL17 signaling.

Adult T-cell leukemia/lymphoma treatment in Bahia, Brazil.

BACKGROUND: Adult T-cell leukemia/lymphoma is a peripheral disease associated with human T-cell lymphotropic virus type 1. Treatment is carried out according to clinical type with watchful waiting being recommended for less aggressive types. Aggressive adult T-cell leukemia/lymphoma is generally treated with chemotherapy and/or antivirals. The objective of this study was to correlate the survival of patients diagnosed in Bahia, Brazil, with the therapeutic approaches employed and to evaluate what issues existed in their treatment processes. METHODS: Eighty-three adult T-cell leukemia/lymphoma patients (26 smoldering, 23 chronic, 16 acute, 13 lymphoma and five primary cutaneous tumoral) with available data were included in this study. RESULTS: Complete response was achieved in seven smoldering patients with symptomatic treatment, in two with chronic disease using antivirals/chemotherapy, in one with acute disease using antivirals and in one lymphoma using the LSG15 regimen [vincristine, cyclophosphamide, doxorubicin, and prednisolone (VCAP); doxorubicin, ranimustine, and prednisolone (AMP); and vindesine, etoposide, carboplatin, and prednisolone (VECP)]. Smoldering patients who received symptomatic treatment presented longer survival. Favorable chronic patients treated with antivirals presented longer survival compared to the unfavorable subtype. However, for the acute form, first-line chemotherapy was better, albeit without significance, than antivirals. Only one of the patients with lymphoma and primary cutaneous tumors responded. CONCLUSIONS: Watchful waiting associated with phototherapy represents the best option for smoldering adult T-cell leukemia/lymphoma with survival in Bahia being superior to that described in Japan. There was a trend of better results with zidovudine/interferon-alpha in favorable chronic disease. Excellent results were achieved in the lymphoma type treated with the LSG15 protocol. Patients are diagnosed late probably due to lack of knowledge of adult T-cell leukemia/lymphoma by primary healthcare doctors and a Brazilian treatment protocol needs to be established.

Adult T-cell leukemia/lymphoma treatment in Bahia, Brazil

Abstract Background: Adult T-cell leukemia/lymphoma is a peripheral disease associated with human T-cell lymphotropic virus type 1. Treatment is carried out according to clinical type with watchful waiting being recommended for less aggressive types. Aggressive adult T-cell leukemia/lymphoma is generally treated with chemotherapy and/or antivirals. The objective of this study was to correlate the survival of patients diagnosed in Bahia, Brazil, with the therapeutic approaches employed and to evaluate what issues existed in their treatment processes. Methods: Eighty-three adult T-cell leukemia/lymphoma patients (26 smoldering, 23 chronic, 16 acute, 13 lymphoma and five primary cutaneous tumoral) with available data were included in this study. Results: Complete response was achieved in seven smoldering patients with symptomatic treatment, in two with chronic disease using antivirals/chemotherapy, in one with acute disease using antivirals and in one lymphoma using the LSG15 regimen [vincristine, cyclophosphamide, doxorubicin, and prednisolone (VCAP); doxorubicin, ranimustine, and prednisolone (AMP); and vindesine, etoposide, carboplatin, and prednisolone (VECP)]. Smoldering patients who received symptomatic treatment presented longer survival. Favorable chronic patients treated with antivirals presented longer survival compared to the unfavorable subtype. However, for the acute form, first-line chemotherapy was better, albeit without significance, than antivirals. Only one of the patients with lymphoma and primary cutaneous tumors responded. Conclusions: Watchful waiting associated with phototherapy represents the best option for smoldering adult T-cell leukemia/lymphoma with survival in Bahia being superior to that described in Japan. There was a trend of better results with zidovudine/interferon-alpha in favorable chronic disease. Excellent results were achieved in the lymphoma type treated with the LSG15 protocol. Patients are diagnosed late probably due to lack of knowledge of adult T-cell leukemia/lymphoma by primary healthcare doctors and a Brazilian treatment protocol needs to be established.

Adult T-cell leukemia/lymphoma in South and Central America and the Caribbean: systematic search and review.

Adult T-cell leukemia/lymphoma (ATL) is caused by the human T-cell lymphotropic virus type 1 (HTLV-1) which is endemic in countries of Caribbean and Central and South America. We performed a systematic search and review to identify publications on ATL in these countries to verify if this disease was getting recognition in these regions as well as the characteristics of the observed cases. The median age of 49.4 years was lower than that referred to in Japan. According to our findings in most Brazilian states and in some other countries, ATL is not being recognized and should be strongly considered in the differential diagnosis of T-cell leukemias/lymphomas. Failure to identify these cases may be due to the unsystematic realization of serology for HTLV-1 and phenotypic identification of non-Hodgkin lymphomas that may result from lack of resources. Detection of ATL cases has been more feasible with cooperation from foreign research centers. A huge effort should be made to improve the surveillance system for ATL diagnosis in most of the South- and Central-American and Caribbean countries, and this attitude should be embraced by public organs to support health professionals in this important task.