HIV-2 and HTLV-1 infections in Spain, a non-endemic region.

The annual workshop of the Spanish HIV­2/HTLV Study Group was held at the Instituto de Salud Carlos III in Madrid on December 11, 2013. Nearly 100 experts and researchers in retroviruses other than HIV­1, the classical AIDS agent, convened for a one­day meeting devoted to updating knowledge on the epidemiology of HIV­2 and HTLV-1 infections and discussing new diagnostic and therapeutic strategies, with special attention to non­endemic regions such as Spain. The Group was funded 25 years ago and since then has been responsible for the national registry of cases, recording all relevant information for each subject and inviting them to enroll in a prospective cohort and biobank. Up to the end of 2013, a total of 297 individuals with HIV­2 infection were reported in Spain. All but 10 carry HIV­2 subtype A, with the rest being infected with subtype B. Overall, 71% came from sub­Saharan Africa. During the last decade, the incidence of new HIV­2 infections in Spain has remained fairly stable with around 20 cases per year. At the time of diagnosis, plasma HIV­2 RNA was undetectable in 61% of individuals and values in viremic subjects tended to be low (2.8 logs on average). To date, only 26% of HIV­2 individuals have been treated with antiretrovirals. The CD4 counts, however, only increased above 200 cells/mm³ in 42% of them. On the other hand, 74% of non­treated HIV­2 individuals have > 500 CD4+ T­cells/mm³. As in HIV­1 infection, X4 tropism in HIV­2 is associated with lower CD4 counts. A total of 253 individuals with HTLV-1 infection were reported in Spain by the end of 2013. Overall, 58% came from Latin America. HTLV-1­associated myelopathy was diagnosed in 29 patients and adult T­cell leukemia/lymphoma in 18. The highest incidence occurred in 2013, with 34 new HTLV-1 diagnoses, largely as result of expanding HTLV screening in blood banks. Attempts to reduce HTLV-1 proviral load in symptomatic or asymptomatic patients with elevated HTLV-1 DNA using antiretrovirals have produced poor results, although integrase inhibitors could be more successful. Although no cases of HTLV­3 or ­4 have been identified so far in Spain, 769 individuals have been diagnosed with HTLV­2 infection. Up to 85% of the latest cases are coinfected with HIV­1 and are former intravenous drug users.