DiagnosticPolicy Influence Systematic changes to the healthcare pathways for patients with Human T-cell lymphotropic virus type 1 infection
Human T-cell lymphotropic virus 1 (HTLV-1) is retroviral infection with an estimated 22,000 people infected in England and Wales and a disproportionate burden in specific higher-risk groups, particularly people of black Caribbean origin and those born in West and Central Africa. While most of the virus carries do not develop health conditions which can be linked to the infection, the virus is can cause a form of blood cancer called adult T-cell leukaemia or lymphoma (ATL) and a progressive disease of the nervous system (HTLV-1-associated myelopathy, or HAM, also known as tropical spastic paraparesis (TSP)). The key health impact is not the size of the infected population alone, but the risk of severe lifelong disease and ongoing transmission.
Over the years, research at Imperial College Section of Virology allowed scientists to accumulate knowledge and develop expertise on HTLV. This allowed Imperial to make tangible impact on virus diagnostics and management. Diagnostic tests developed at Imperial have been implemented by the Molecular Diagnostic Unit to deliver routine diagnostic services and directly inform patient management at the National Centre for Human Retrovirology at St Mary’s Hospital. Specifically, genotyping tests confirm HTLV infection and type, coupled with proviral tests that stratify risk, both ultimately guide follow-up frequency, prevention counselling, and specialist monitoring for HTLV-related complications.
In 2024 our modelling study demonstrated that 74 infant infections would be expected in England and Wales per year, at the same time antenatal screening could prevent 58 of these infections and was found cost-effective. Thus, even though HTLV is relatively rare, targeted testing and prevention could meaningfully reduce mother-to-child transmission and long-term morbidity. Our research is directly contributing to the UK NSC consultation on targeted screening. This work is a good example of research potentially moving policy from “no routine screening” toward a more selective, risk-based approach.
Together Imperial and Imperial College Healthcare NHS Trust form a leading centre for both research and clinical practice for HTLV. Imperial College Healthcare NHS Trust hosts the national referral service for HTLV infection through the National Centre for Human Retrovirology (NCHR). Supported by the Molecular Diagnostic Unit, which provide the gold-standard testing facility for HTLV DNA load measurement and HTLV-1/2 typing assays, the NCHR serves as the UK’s principal centre for HTLV-1 and HTLV-2 infection. It delivers comprehensive care, including long-term clinical follow-up, counselling, pregnancy and infant-feeding advice, as well as access to HTLV research studies and clinical trials.
