The human immunodeficiency viruses (HIV) are two species of Lentivirus that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive. Without treatment, the average survival time after infection with HIV is estimated to be 9 to 11 years, depending on the HIV subtype.
Leukemia is a group of blood cancers that usually begin in the bone marrow and produce high numbers of abnormal blood cells. These blood cells are not fully developed and are called blasts or leukemia cells. Symptoms may include bleeding and bruising, bone pain, fatigue, fever, and an increased risk of infections. These symptoms occur due to a lack of normal blood cells. Diagnosis is typically made by blood tests or bone marrow biopsy.
A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. After invading a host cell's cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus retro (backward). The new DNA is then incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along with the cell's own genes, producing the proteins required to assemble new copies of the virus. Many retroviruses cause serious diseases in humans, other mammals, and birds.
Human T-cell lymphotropic virus type 1 or human T-lymphotropic virus (HTLV-I), also called the adult T-cell lymphoma virus type 1, is a retrovirus of the human T-lymphotropic virus (HTLV) family.
Hairy cell leukemia is an uncommon hematological malignancy characterized by an accumulation of abnormal B lymphocytes. The incidence of hairy cell leukemia (HCL) is 0.28-0.30 cases per 100,000 people in Europe and the United States and the prevalence is 3 cases per 100,000 in Europe with a lower prevalence in Asia, Africa and the Middle East.
Adult T-cell leukemia/lymphoma is a rare cancer of the immune system's T-cells caused by human T cell leukemia/lymphotropic virus type 1 (HTLV-1). All ATL cells contain integrated HTLV-1 provirus further supporting that causal role of the virus in the cause of the neoplasm. A small amount of HTLV-1 individuals progress to develop ATL with a long latency period between infection and ATL development. ATL is categorized into 4 subtypes: acute, smoldering, lymphoma-type, chronic. Acute and Lymphoma-type are known to particularly be aggressive with poorer prognosis.
Mycosis fungoides, also known as Alibert-Bazin syndrome or granuloma fungoides, is the most common form of cutaneous T-cell lymphoma. It generally affects the skin, but may progress internally over time. Symptoms include rash, tumors, skin lesions, and itchy skin.
An oncovirus or oncogenic virus is a virus that can cause cancer. This term originated from studies of acutely transforming retroviruses in the 1950–60s, when the term oncornaviruses was used to denote their RNA virus origin. With the letters RNA removed, it now refers to any virus with a DNA or RNA genome causing cancer and is synonymous with tumor virus or cancer virus. The vast majority of human and animal viruses do not cause cancer, probably because of longstanding co-evolution between the virus and its host. Oncoviruses have been important not only in epidemiology, but also in investigations of cell cycle control mechanisms such as the retinoblastoma protein.
Cutaneous T-cell lymphoma (CTCL) is a class of non-Hodgkin lymphoma, which is a type of cancer of the immune system. Unlike most non-Hodgkin lymphomas, CTCL is caused by a mutation of T cells. The cancerous T cells in the body initially migrate to the skin, causing various lesions to appear. These lesions change shape as the disease progresses, typically beginning as what appears to be a rash which can be very itchy and eventually forming plaques and tumors before spreading to other parts of the body.
Deltaretrovirus is a genus of the Retroviridae family. It consists of exogenous horizontally transmitted viruses found in several groups of mammals. As of 2023, ICTV lists under this genus the Bovine leukemia virus and three species of primate T-lymphotropic virus.
Following infection with HIV-1, the rate of clinical disease progression varies between individuals. Factors such as host susceptibility, genetics and immune function, health care and co-infections as well as viral genetic variability may affect the rate of progression to the point of needing to take medication in order not to develop AIDS.
Sézary disease, or Sézary syndrome, is a type of cutaneous T-cell lymphoma that was first described by Albert Sézary. The affected T cells, known as Sézary's cells or Lutzner cells, have pathological quantities of mucopolysaccharides. Sézary disease is sometimes considered a late stage of mycosis fungoides with lymphadenopathy.
T-cell lymphoma is a rare form of cancerous lymphoma affecting T-cells. Lymphoma arises mainly from the uncontrolled proliferation of lymphocytes, such as T-cells, and can become cancerous.
Bovine leukemia virus (BLV) is a retrovirus which causes enzootic bovine leukosis in cattle. It is closely related to the human T‑lymphotropic virus type 1 (HTLV-I). BLV may integrate into the genomic DNA of B‑lymphocytes as a DNA intermediate, or exist as unintegrated circular or linear forms. Besides structural and enzymatic genes required for virion production, BLV expresses the Tax protein and microRNAs involved in cell proliferation and oncogenesis. In cattle, most infected animals are asymptomatic; leukemia is rare, but lymphoproliferation is more frequent (30%).
Robert Charles Gallo is an American biomedical researcher. He is best known for his role in establishing the human immunodeficiency virus (HIV) as the infectious agent responsible for acquired immune deficiency syndrome (AIDS) and in the development of the HIV blood test, and he has been a major contributor to subsequent HIV research.
The primate T-lymphotropic viruses (PTLVs) are a group of retroviruses that infect primates, using their lymphocytes to reproduce. The ones that infect humans are known as human T-lymphotropic virus (HTLV), and the ones that infect Old World monkeys are called simian T-lymphotropic viruses (STLVs). PTLVs are named for their ability to cause adult T-cell leukemia/lymphoma, but in the case of HTLV-1 it can also cause a demyelinating disease called tropical spastic paraparesis. On the other hand, newer PTLVs are simply placed into the group by similarity and their connection to human disease remains unclear.
Lennert lymphoma, also termed lymphoepithelioid lymphoma, lymphoepithelioid variant of peripheral T-cell lymphoma, and epithelioid cellular lymphogranulomatosis, is a rare subtype of the T cell lymphomas. It was first characterized by Karl Lennert in 1952 as a variant of Hodgkin lymphoma based on the presence of cells resembling the Reed–Sternberg cells that typify Hodgkin lymphoma. However, later studies concluded that these cells are not Reed-Sternberg cells and that Lennert lymphoma is not a variant of Hodgkin lymphoma.
Indolent lymphoma, also known as low-grade lymphoma, is a group of slow-growing non-Hodgkin lymphomas (NHLs). Because they spread slowly, they tend to have fewer signs and symptoms when first diagnosed and may not require immediate treatment. Symptoms can include swollen but painless lymph nodes, unexplained fever, and unintended weight loss.
William W. Hall is the chair of medical microbiology and professor emeritus at the Centre for Research in Infectious Diseases at University College Dublin.
T-cell acute lymphoblastic leukemia (T-ALL) is a type of acute lymphoblastic leukemia characterized by an aggressive malignant neoplasm of the bone marrow. Acute lymphoblastic leukemia (ALL) is a condition, wherein immature white blood cells accumulate in the bone marrow and crowd out normal white blood cells. Accumulation in the liver, spleen, and lymph nodes frequently occurs as well.
