Conference highlights of the 16th International Conference on Human Retrovirology: HTLV and related retroviruses, 26-30 June 2013, Montreal, Canada

Molecular investigation of possible relationships concerning bovine leukemia virus and breast cancer

Worldwide, breast cancer has an eminent morbidity and mortality rate, as it is a neoplastic disease among females. The query of the prospective danger of bovine leukemia virus (BLV) to humans is an old but exceedingly topical focus of scientific debate. The objective of the current study was to determine the possible relationship between BLV and breast cancer. A total of 2710 formalin-fixed paraffin-embedded (FFPE) breast cancer samples were selected regardless of the age, ethnicity, or municipality origin of the subjects. The presence of BLV in human breast cancer was determined through nested PCR by amplifying tax and gag genes followed by partial sequencing. Homology was confirmed by using the online BLAST Tool. BLV genes were found to be positive in 26.8% (728/2710) of the samples from breast cancer patients and 10% (10/80) of the samples without cancer (negative control). The results indicated a correlation between the presence of the BLV gene and breast cancer (odds ratio = 0.3889; confidence interval = 1,18; p = 0.0029). The current findings suggest a possible link between BLV and human breast carcinoma. Therefore, screening cattle herds and milk products is suggested to reduce the viral transmission risk to humans.

Morphological alterations in minor salivary glands of HTLV1+ patients: A pilot study

BACKGROUND

Among the complex of HTLV-associated diseases, Sjögren's syndrome (SS) is one of the most controversial. This work aims to detect morphological and inflammatory alterations, including clues of the presence of HTLV-1, in minor salivary glands of patients with dryness symptoms.

METHODS

We have assessed HTLV-1-seropositive patients (HTLV-1 group) and patients with SS (SS group). We used formalin-fixed, paraffin-embedded minor salivary gland tissue to evaluate the morphological aspects and, by means of immunohistochemistry, the presence of Tax protein, CD4, CD8 and CD20 cells. Additionally, viral particles and proviral load were analysed by PCR.

RESULTS

The HTLV-1 group had the highest prevalence of non-specific chronic sialadenitis (85.71%; P = 0.017) and greater amount of T CD8⁺ cells. In the SS group, focal lymphocytic sialadenitis (80%; P = 0.017) prevailed, with a greater amount of B CD20⁺ . Both immunohistochemistry and PCR identified the Tax protein and its gene in the salivary glands of both groups and in similar proportions.

CONCLUSION

The results indicate that HTLV-1-seropositive patients have different patterns of morphological/inflammatory alterations, suggesting a likely difference in the process of immune activation.

Adult T-cell leukemia/lymphoma

Summary Adult T-cell leukemia/lymphoma (ATL) is a malignancy of mature CD4+ T-cells caused by human T-cell lymphotropic virus type 1 (HTLV-1). Twenty million people are believed to be infected throughout the world, mostly in Japan, Africa, the Caribbean, and South America, particularly in Brazil and Peru. ATL affects about 5% of infected individuals and is classified in the following clinical forms: acute, lymphoma, primary cutaneous tumoral, chronic (favorable and unfavorable), and smoldering (leukemic and non-leukemic). Although it is considered an aggressive disease, there are cases with a long progression. We emphasize the importance of clinical classification as an indispensable element for evaluating prognosis and appropriate therapeutic approach. Since several cases have been published in Brazil and this disease is still poorly known, we decided to make a review paper for dissemination of clinical, hematological and pathological aspects, diagnosis, and therapy. The best way to reduce the occurrence of ATL would be halting the transmission of the virus through breastfeeding.

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.