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

Infection with human T-lymphotropic virus types-1 and -2 (HTLV-1 and -2): Implications for blood transfusion safety.

Many countries currently perform antibody screening for HTLV-1 infection in blood donors, and this intervention is likely cost-effective in preventing HTLV-1 related diseases in high prevalence countries. However, a number of high-income countries with low prevalence of HTLV-1 infection also perform universal HTLV-1 screening and debate has arisen regarding the cost-effectiveness of these strategies. Filter-based leukoreduction is likely to substantially reduce HTLV-1 transmission by removing infected lymphocytes, but actual laboratory data on its efficacy is currently lacking. Similarly, cost-effectiveness research on HTLV-1 prevention strategies is limited by poor data on prevalence, transmission efficacy and the cost of treating HTLV1 diseases.

Human T-lymphotropic virus and transfusion safety: does one size fit all?

Human T-cell leukemia viruses (HTLV-1 and HTLV-2) are associated with a variety of human diseases, including some severe ones. Transfusion transmission of HTLV through cellular blood components is undeniable. HTLV screening of blood donations became mandatory in different countries to improve the safety of blood supplies. In Japan and Europe, most HTLV-infected donors are HTLV-1 positive, whereas in the United States a higher prevalence of HTLV-2 is reported. Many industrialized countries have also introduced universal leukoreduction of blood components, and pathogen inactivation technologies might be another effective preventive strategy, especially if and when generalized to all blood cellular products. Considering all measures available to minimize HTLV blood transmission, the question is what would be the most suitable and cost-effective strategy to ensure a high level of blood safety regarding these viruses, considering that there is no solution that can be deemed optimal for all countries.

[HTLV and "donating" milk]. / HTLV-1 et don de lait maternel.

In France, the screening for human T-cell leukemia/ lymphoma virus type 1 and 2 (HTLV-1 and HTLV-2) during the donation of human milk has been carried out from 1992 with the application of the circular DGS 24 November 1992. The screening for antibodies against these viruses is regulated and done systematically during every donation of milk. Breast feeding being the main mode of transmission of the HTLV-1, the last ministerial decree of 25 August 2010 has made the screening test compulsory for the anonymous donation and for the personalized donation (of a mother for her own child) from all women including those affected by the infection. The milk delivered by milk banks is pasteurized (62.5 °C for 30 minutes) before freezing at -18 °C, which inactivates the pathogens. This double means of prevention of the transmission of the HTLV-1 paradoxically seems disproportionate in the absence of any precautionary measure in the case of direct breast-feeding and the use of mother's raw milk. Indeed, in most neonatal intensive care units in maternity hospitals, unpasteurized milk is administered to the neonates without any systematic preliminary testing of the serological HTLV-1 status of the mother. An increased sensitization of the community of the obstetricians, midwives and neonatologists by the Association of the Milk Banks of France (ADLF) and the Société de pathologie exotique could address the issue of screening for HTLV-1 in "donated" milk and breast-feeding.

Strategies for diagnosis of HTLV-I and -II.

BACKGROUND: No gold standard exists for diagnosis of HTLV infection. The aim of thus study was to compare the accuracy of a combination of two sensitive ELISAs with Western blot (WB), a line immunoassay, and PCR for diagnosis of HTLV infection. STUDY DESIGN AND METHODS: Nine hundred eighty-five specimens were tested for the presence of HTLV antibodies by HTLV-I and/or HTLV-II EIAs (Murex and Ortho), WB (Diagnostic Biotechnology), line immunoassay (INNO-LIA, Innogenetics), and/or presence of HTLV DNA by PCR. The results were compared with the probable HTLV infection status of each subject, as determined by detailed review of all available laboratory, clinical, and epidemiologic data. RESULTS: The sensitivity for diagnosis of HTLV-I infection was high for all assays evaluated, but both PCR and WB had a lower sensitivity rate (approx., 80%) for confirmation of HTLV-II. INNO-LIA detected 94 percent of the HTLV-II-positive samples. However, Murex EIA in combination with Ortho EIA was 100-percent sensitive for the detection of both HTLV-I and HTLV-II antibodies. Furthermore, the number of samples giving indeterminate results in the ELISA combination was much lower as compared with WB (2.5% vs. 50%). CONCLUSION: Based on these findings, a new, more sensitive and specific test strategy for HTLV diagnosis than the current algorithm, which includes WB, is proposed. Thereby, both the direct and indirect costs can be substantially reduced.

[Cost-effective approach to the screening of HIV, HBV, HCV, HTLV in blood donors in France]. / Approche coût-efficacité du dépistage des virus VIH, VHB, VHC, HTLV chez les donneurs de sang en France.

In order to provide greater safety in blood transfusions, public health authorities have imposed the use of screening tests. The purpose of this paper is to estimate the cost-effectiveness ratios of the screening test used in France. Four risks were studied: HIV, HBV, HCV and HTLV. Two efficiency measures were used: cost per positive blood donation detected and cost per case of prevented infection transmission. Moreover, for HTLV alone, the efficiency was estimated by the cost per prevented pathology. Data concerning the costs were provided by the French Blood Agency; those concerning the results of the screening campaigns were provided by the official health authorities, the other data used in the calculations were drawn either from the French Blood Agency data or from a review of international literature. Results gave information about the expenditure devoted to the screening of virologic risks associated with blood transfusion in France (250 million francs per year for the four viruses studied). They stressed the differences in screening efficiency according to the test studied (the cost by prevented seroconversion varied from 31,795 francs for HBV, 72,180 francs for HCV, 676,596 francs for HIV to 6,137,346 francs for HTLV screening test in the base case) and especially the very low efficiency of the systematic screening of the HTLV virus (from 34 to 307 million francs per prevented leukemia).

Seroepidemiology of HTLV-I/II in universal screening of blood donations in France.

OBJECTIVE: To evaluate the serological and epidemiological characteristics of HTLV-I/II-positive blood donors in continental France during the first 6 months of universal screening of blood donations (n = 1,816,927). METHOD: A collaborative investigation of all confirmed anti-HTLV-I/II-positive samples reported by blood transfusion centres was performed. Seventy-three out of 77 reported samples were retested at two reference laboratories. Epidemiological data on risk factors were compiled. RESULTS: Of the 73 retested samples, 66 were confirmed to be HTLV-I-positive and one to be HTLV-II-positive; six samples were designated false-positive, mainly because of non-specific reactivity to recombinant gp21 in Western blot. The overall prevalence of HTLV-I/II in continental France is 0.039 per thousand. The main risk factor identified for HTLV-I infection was directly (origin) or indirectly (heterosexual contact) linked to endemicity in the Caribbean. The cost per case of avoided contamination in the 6-month period of this study was 1.36 million French francs. CONCLUSIONS: Sixty-two per cent of HTLV-I/II-infected blood donations would not have been discarded through the previous targeted HTLV screening or through other mandatory tests, including anti-hepatitis B core. To avoid false-positive results, we propose a new algorithm of diagnosis.

Assessment of a retrovirus sequence and other possible risk factors for the chronic fatigue syndrome in adults.

OBJECTIVE: To assess whether the human T-lymphotropic virus type II (HTLV-II) gag gene sequence, a purportedly new laboratory marker of the chronic fatigue syndrome (CFS), and other possible risk factors for CFS, particularly those associated with retroviral transmission, are associated with well-characterized CFS. DESIGN: Two matched case-control studies. SETTING: The metropolitan Atlanta area. PATIENTS: Twenty-one patients with CFS who were identified by the Centers for Disease Control and Prevention CFS surveillance system; 21 CDC employee controls (laboratory study) and 42 neighborhood controls (risk-factor study) who were matched to patients by age, race, and gender. MEASUREMENTS: Peripheral blood lymphocytes and leukocytes were assayed for the HTLV-II gag gene sequence by polymerase chain reaction and specific Southern blot hybridization. Questionnaires elicited demographic and clinical information and a history of exposures associated with retrovirus transmission (for example, blood transfusions, sexual practices, intravenous drug use). RESULTS: All patients were white and 86% were female. The median age at illness onset was 34 years (range, 16 to 51 years). The HTLV-II gag gene sequence was not identified in the blood of any patient or control under conditions in which the appropriate assay controls were positive. No statistical differences were observed between patients and controls in frequency of blood transfusions (10% compared with 7%), median number of sex partners before illness (3 compared with 3), bisexual or homosexual behavior (14% compared with 7%), intravenous drug use (0% compared with 0%), and other factors associated with retroviral infection. CONCLUSIONS: The HTLV-II gag gene sequence was not a marker for CFS in this small study of well-defined patients, nor did other characteristics of the patients and controls support the hypothesis that a retrovirus, transmitted by usual modes, was a cause of CFS.