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Research of human T lymphotropic virus type I (HTLV-1)-associated diseases is mostly focused on inflammatory and lymphoproliferative disorders. However, the immunosuppressive consequences of HTLV-1 infection are frequently ignored. In developing countries where exposure to parasitic and other tropical diseases is frequent, the burden of disease is significantly increased by opportunistic infections. Regulatory T cells (Tregs) are a CD4 T-cell subset capable of suppressing effector responses. During HTLV-1 infection, CD4+Foxp3+ cells are increased in HTLV-1-associated leukaemia/lymphoma (ATLL) as well as in non-leukaemic presentations. However, controversy exists regarding the actual regulatory function of these cells. In this report, we present two cases of HTLV-1 ATLL complicated by parasitic organisms and we provide a brief review of the literature regarding FoxP3+ regulatory T cells and their role as a possible mechanism for the immunosuppressive manifestations that take place during HTLV-1 infection. [ABSTRACT FROM AUTHOR]

Begomoviruses cause losses in several crops around the world. Whiteflies of the Bemisia tabaci cryptic species MEAM1 and MED are efficient vectors of begomoviruses. MEAM1 has been the predominant species in Brazil since the mid‐1990s. MED was detected in Brazil in 2014, and since then, high insect infestations have been reported, mainly in greenhouse production of solanaceous crops. In this study, we compared the transmission efficiency of the begomoviruses tomato severe rugose virus (ToSRV) and tomato rugose mosaic virus (ToRMV) to tomato (Solanum lycopersicum) and bean golden mosaic virus (BGMV) to common bean (Phaseolus vulgaris) by a population of MEAM1 and four populations of MED. B. tabaci MEAM1 efficiently transmitted ToSRV and ToRMV to tomato and BGMV to common bean. B. tabaci MED populations did not transmit ToSRV and ToRMV to tomato. Only one population of B. tabaci MED transmitted BGMV with an efficiency of 3%. PCR analysis indicated that B. tabaci MED can acquire ToSRV, ToRMV and BGMV after a 24 h acquisition access period. Furthermore, some greenhouse tomato plantings from São Paulo state were surveyed for the presence of viruses and whiteflies, and B. tabaci MED were predominant, whereas begomoviruses were absent. Our results demonstrate that populations of MED from São Paulo state are inefficient vectors of begomoviruses, being able to acquire the virus but not transmit it to plants. Understanding this interaction is important and suggests that the spread of B. tabaci MED could change the epidemiological scenario of begomoviruses in areas where this insect predominates. [ABSTRACT FROM AUTHOR]