Background: The Human T Cell Lymphotropic Virus (HTLV) is a retrovirus of the genus Deltaretrovirus, which belongs to the family Retroviridae, and has tropism for T lymphocytes. This virus has four types, of which the most important in terms of pathogenesis and epidemiology are HTLV-1 and HTLV -2. It is estimated that between five and 10 million individuals are infected with HTLV-1, worldwide, of which, approximately 2.5 million live in Brazil. Studies in the state of Pará indicate that it has the third highest prevalence of HTLV infections of any Brazilian state. The virus can betransmitted through sexual, vertical, and parenteral route. The present study describes the epidemiological, serological, and molecular profile of blood donors from the state of Pará, that were classified as unfit due to infection by HTLV-1 and 2. Results: A total of 632 samples were analyzed. The HTLV proviral DNA was detected primarily in females (69.1%), with a mean age of 40 years, with the highest frequencies of detection being recorded in single individuals (66.2%), first-time donors (74.3%), and individuals that had graduated high school (44.1%). The molecular confirmation of HTLV showed that threequarters (78%) of the serologically reactive individuals were negative for either types I or II, so the epidemiological profile of these individuals was significantly different from their detectable profile. Conclusions: The HTLV is a neglected etiological agent in Brazil, and although there have been many advances since its discovery, infection patterns are still relatively poorly understood by both healthcare professionals and the general population. There is thus a clear need for further research in the area of regional hemotherapy and hematology services, in order to contribute to the definition of regional infection profiles, that will be fundamental to the development of effective prophylactic practises for the prevention of the infection and the dissemination of knowledge on the dangers of HTLV in the community.

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The present study aims to correlate the sample-to-cutoff ratios (S/CO) distributions of reactive results for HTLV-1/2 antibodies with the detection of proviral DNA in a population of blood donor candidates. It was carried out a retrospective data search of 632 HTLV-1/2 reactive samples, submitted to confirmatory testing from January 2015 to December 2019. Serological screening was performed by chemiluminescent microparticle immunoassay Architect rHTLV-I/II, whereas confirmatory testing was performed by in-house real-time polymerase chain reaction method. 496 out of 632 samples (78%) had undetectable HTLV-1/2 proviral DNA and 136 (22%) had detectable proviral DNA. HTLV infection was not confirmed in any individual for whom the S/CO ratio value was <4, and proviral DNA detection rates gradually escalated as S/CO ratio values increased. The sensitivity and predictive positive value found for the Architect rHTLV-I/II was 100% and 22%, respectively. The receiver operating characteristic (ROC) curve analysis showed that the optimal S/CO ratio value for predicting the presence of HTLV-1/2 was 18.11. High S/CO ratios were more associated with the detection of proviral DNA. The S/CO ratio value <4 suggests excluding true HTLV infection and the risk of blood transmission.

Objective: This study describes the hematological parameters associated with the BCR-ABL gene transcripts in patients with chronic myeloid leukemia (CML). Methods: We reviewed the results of 100 detectable patients for one of the BCR-ABL gene transcripts. The eligibility criteria were based on the presence of one of the leukemic transcripts (b2a2, b3a2, and b2a2/b3a2) and complete epidemiological and hematological data. The data were obtained from the LabMaster computerized system. The Kruskal-Wallis test was used to compare the medians of the quantitative variables between the transcripts of the BCR-ABL gene and the chi-square test to compare the qualitative ones, adopting the p-value with a level of significance less than or equal to 0.05. Results: Forty-five patients (45%) presented the b2a2 transcript, 24 (24%) the b3a2 transcript and 31 (31%) a b2a2/b3a2 coexpression. Individuals who expressed the b3a2 transcript had higher leukocyte counts and platelet levels, but we found no differences compared with individuals who expressed the other transcript. Conclusion: In this study, the BCR-ABL gene transcripts did not influence the hematological parameters of patients with CML.

The present study describes HTLV seroprevalence in potential blood donors from the Brazilian state of Pará, and the sociodemographic characteristics of the infection in this state. This descriptive, retrospective, and cross-sectional study is based on secondary serological and sociodemographic data on potential blood donors who were rejected for presenting reactive results in the serological HTLV screening between January 2010 and December 2020. The mean HTLV seroprevalence was 0.2%. The highest frequency of reactivity was recorded in first-time donors, women, individuals over 30 years old that were single and had a relatively low level of  education. There have been many advances since the discovery of HTLV, although it is still considered to be a neglected etiological agent in Brazil. Further research on data from hematological services will be necessary to refine regional infection profiles, which will be fundamental for the development of adequate prophylactic practises to control and prevent infection, as well the dissemination of information on the dangers of HTLV to the general population.