What family is human T-cell leukemia virus?
Human T Cell lymphotropic viruses (HTLV) are a family of retroviruses.
Key facts. The human T-lymphotropic virus type 1 is also known by the acronym HTLV-1, or as human T-cell leukaemia virus type 1. The virus can cause a type of cancer called adult T-cell leukaemia/lymphoma (ATL). HTLV-1 is transmitted primarily through infected bodily fluids including blood, breast milk and semen.
Human T-lymphotropic viruses, type I (HTLV-I) and type II (HTLV-II), were the first human retroviruses discovered (1,2). Both belong to the oncovirus subfamily of retroviruses and can transform human lymphocytes so that they are self-sustaining in vitro.
Human T-Cell Lymphotropic Virus I/II
HTLV types I and II are two closely related RNA viruses that can be transmitted through body fluids.
Adult T cell leukemia is primarily caused by HTLV-1 infection that is transmitted through breastfeeding, sexual contact, and blood transfusion. Although most of the individuals who carry HTLV-1 infection remain asymptomatic, they are at an increased lifetime risk for developing ATL.
Patients with T-PLL often have genetic changes to their T-cells called a T-cell receptor rearrangement, which is linked to abnormal T-cell growth. This type of genetic change occurs from damage to the genes during a person's life. It is not passed from parent to child. Adult T-cell leukemia/lymphoma (ATLL).
In general, leukemia occasionally can be caused by a genetic mutation or change. These may be genetic mutations passed from generation to generation within a family or from environmental factors, such as smoking or exposure to chemicals or radiation. However, most often the cause of leukemia is not known.
HTLV-II has been associated with two chronic neurologic disorders similar to those caused by HTLV-I, tropical or spastic ataxia. A connection between HTLV-II and glomerulonephritis, myelopathy, arthritis, T-hairy cell leukemia, and large-cell granulocytic leukemia has been reported.
The HTLV-1 virus infects CD4+ T lymphocytes, and can modify the cell function. CD4+ T lymphocytes are the central acquired immune response regulators. Changes in their behavior can trigger inflammatory reactions that can break immune system tolerance, leading to autoimmunity.
HTLV-1 is the causal agent of adult T-cell leukemia and a progressive neurological disorder called HTLV-1-associated myelopathy/tropical spastic paraparesis (12, 34, 54). In contrast, HTLV-2 is essentially nonpathogenic, although a few cases of neurological disease in HTLV-2-infected individuals have been reported.
Is T-cell leukemia the same as T-cell lymphoma?
T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL) are considered the same disease, differing by the extent of bone marrow infiltration.
The t-Virus is an RNA virus that takes the genetic code modifying properties of the Progenitor Virus base and improves upon it, resulting in the potential to create devastating new B.O.W.s. But to reach that point, countless experiments were conducted on various living organisms and there were many failures along the ...
Both DNA and RNA viruses have been shown to be capable of causing cancer in humans. Epstein-Barr virus, human papilloma virus, hepatitis B virus, and human herpes virus-8 are the four DNA viruses that are capable of causing the development of human cancers.
The outlook for an individual with T-ALL is generally good. Children have an overall survival rate of more than 85% after 5 years, although this figure is less than 50% in adults. One reason for this could be that children may handle high levels of chemotherapy more effectively than adults.
Adult T-cell leukaemia/lymphoma (ATL or ATLL) is a rare type of non-Hodgkin lymphoma that affects about 1 in 20 people who have a virus called 'human T-lymphotropic virus type 1' (HTLV-1).
Virtually all patients with T-ALL will start treatment immediately. The main exception would be if a patient is very ill with other medical problems and is not fit enough to receive treatment. Acute leukaemia is often curable with standard treatments, in younger and/or fitter patients.
Adult T-cell leukemia/lymphoma (ATLL) is a rare and often aggressive (fast-growing) T-cell lymphoma that can be found in the blood (leukemia), lymph nodes (lymphoma), skin, or multiple areas of the body.
It's a genetic disease, but most cases aren't thought to be hereditary. Instead, a variety of risk factors can make you more likely to get the disease. Some of these risk factors are in your control, others aren't. Scientists think the various types of leukemia are caused by mutations in the DNA of your blood cells.
The overall survival rates were 13.3% ± 11.0% for ETP-ALL and 64.7% ± 6.3% for non-ETP-ALL (P = 0.002). Our findings demonstrate that early T-cell precursor leukemia is a very high-risk subtype of acute lymphoblastic leukemia with poor prognosis.
Asian race was associated with increased risk of AML with OR=1.643, 95% CI: 1.10–2.46 for Asian vs. Whites and with OR=1.67, 95% CI: 1.04–2.70 for Asian/Asian vs. White/White. Hispanic ethnicity was associated with increased risk of ALL (OR=1.37, 95% CI: 1.22–1.52).
What is the survival rate of T-ALL leukemia by age?
| Age group | % of deaths |
|---|---|
| 20–34 | 2.4 |
| 35–44 | 2.3 |
| 45–54 | 4.8 |
| 55–64 | 12.1 |
Leukemia does not tend to run in families and therefore is not usually hereditary. Some people inherit genetic features that increase their risk, but this does not mean they will develop the condition.
In the Americas, HTLV-1 has more than one origin, being brought by immigrants in the Paleolithic period through the Bering Strait, through slave trade during the colonial period, and through Japanese immigration from the early 20th century, whereas HTLV-2 was only brought by immigrants through the Bering Strait.
HTLV-2 is spread by blood transfusions, sexual contact and sharing needles. It can also be spread from mother to child during birth or breast-feeding.
HTLV-1 is present throughout the world with clusters of high endemicity in southern Japan, the Caribbean region, areas of South America and tropical Africa and foci in the Middle East, Australia and Melanesia.
Human T-cell leukemia virus type 1 is spread by sharing syringes or needles, through blood transfusions or sexual contact, and from mother to child during birth or breast-feeding.
No treatments exist for acute or chronic HTLV infection. Antiretroviral agents have demonstrated the ability to inhibit HTLV replication, but there has been limited research in asymptomatic carriers of HTLV-1, in whom the proviral load is already typically low.
A positive HTLV-I/II molecular test indicates that the person tested has an HTLV-I or HTLV-II infection. If the molecular result is negative, then the person is less likely to be infected, but it cannot be ruled out as the amount of virus in the blood may have been too low to detect at the time of the test.
Initial symptoms are subtle and include gait problems, unexplained falls, low back pain, constipation, urinary urgency/incontinence and numbness or pain in the lower limbs. Over the years, progressive leg weakness ensues followed by the exacerbation of the urinary and sensory symptoms.
A false-positive test result means that the initial screening test was reactive, but a more precise supplemental test was negative. Almost all false-positive test results occur because of interference with the test and are not due to infection. They are not testing errors.
What is HTLV-1 neurological disease?
HTLV-1–Associated Myelopathy
HAM is a neuroinflammatory disease of the spinal cord. Patients with HAM typically experience chronic lower back pain with early neuropathic urinary bladder symptoms followed by the development of lower limb spasticity.
T-cell prolymphocytic leukemia (T-PLL) is an extremely rare and typically aggressive malignancy (cancer) that is characterized by the out of control growth of mature T-cells (T-lymphocytes). T-cells are a type of white blood cell that protects the body from infections.
- progressive muscle weakness in the legs.
- muscle stiffness and spasms.
- lower back pain.
- not being able to control your bladder (wee) or bowels (poo)
The Agent. Human T-lymphotropic viruses, HTLV, comprise a family of four related retroviruses that affect T-cells, a type of white blood cell. The viruses are thought to have passed from monkeys into humans, and simian counterparts of three of the four viruses have been identified.
ATL is often aggressive and difficult to treat. Those with a slow-growing subtype, such as smoldering ATL, usually have a better prognosis. The treatment may involve chemotherapy, antiviral drugs, or stem cell transplantation.
[1] Although approximately 95% of those who contract HTLV-1 will be asymptomatic, the remaining 5% may develop fatal malignant, inflammatory, or opportunistic disease.
Adult T-cell leukemia/lymphoma (ATLL).
ATLL may be treated with zidovudine (Retrovir) and recombinant interferon alpha if it is in the chronic or acute phase. The goal of treatment is to strengthen the immune system and treat the human T-cell leukemia virus (HTLV).
Angioimmunoblastic T cell lymphoma (AITL)
Generally for people with angioimmunoblastic T cell lymphoma (AITL): almost 35 in 100 people (almost 35%) survive for 5 years or more.
How many people are diagnosed with T-cell leukemia? In 2023, an estimated 18,740 people (12,130 males and 6,610 females) in the United States will be diagnosed with a main type of leukemia called chronic lymphocytic leukemia (CLL).
In the United States, the overall prevalence of HTLV infection is 22 per 100,000 population, with HTLV-2 more common than HTLV-1. Data collection performed from 2000-2009 among US blood donors has shown a general decline since the 1990s.
Can you be born with HTLV?
Virtually all babies born from HTLV-1 infected mothers have anti-HTLV-1 antibody at birth. These antibodies decrease exponentially in the first 3–6 months and most babies are seronegative at 6–9 months.