Human T-cell leukemia lymphoma viruses (HTLV), also known as human T-lymphotropic virus, are a group of retroviruses that primarily infect human T-cells, a type of white blood cell crucial to the immune system. These viruses belong to the family Retroviridae and the subfamily Orthoretrovirinae. There are four distinct types of HTLV viruses: HTLV-1, HTLV-2, HTLV-3, and HTLV-4.
HTLV viruses are known to cause various diseases in humans, including T-cell leukemia, a cancer of the T-cells, and lymphoma, a cancer of the lymphatic system. HTLV-1 is particularly associated with the development of adult T-cell leukemia/lymphoma (ATLL), which is characterized by the uncontrolled growth of infected T-cells. The mechanism by which HTLV viruses cause these diseases involves the integration of viral DNA into the host genome and subsequent alteration of cellular functions related to cell growth and immune response.
Transmission of HTLV viruses primarily occurs through sexual intercourse, blood transfusion, and breastfeeding. Vertical transmission from mother to child during childbirth or breastfeeding is a significant route for HTLV-1. However, not all individuals infected with HTLV viruses develop leukemia or lymphoma. It is estimated that less than 5% of HTLV-1 carriers will eventually develop ATLL.
There is currently no cure for HTLV infections, and treatment options mainly focus on managing the symptoms and complications associated with the diseases caused by these viruses. Preventive measures such as practicing safe sex, avoiding sharing needles, and implementing appropriate screening strategies for blood transfusions can help reduce the spread of HTLV infections.
