Progressive multifocal leukoencephalopathy (PML) is a rare and often fatal viral disease characterized by progressive damage (-pathy) or inflammation of the white matter (leuko-) of the brain (-encephalo-) at multiple locations (multifocal). It is caused by the JC virus, which is normally present and kept under control by the immune system. The JC virus is harmless except in cases of weakened immune systems. In general, PML has a mortality rate of 30–50% in the first few months, and those who survive can be left with varying degrees of neurological disabilities.
Tacrolimus, sold under the brand name Prograf among others, is an immunosuppressive drug. After allogenic organ transplant, the risk of organ rejection is moderate. To lower the risk of organ rejection, tacrolimus is given. The drug can also be sold as a topical medication in the treatment of T-cell-mediated diseases such as eczema and psoriasis. For example, it is prescribed for severe refractory uveitis after a bone marrow transplant, exacerbations of minimal change disease, Kimura's disease, and vitiligo. It can be used to treat dry eye syndrome in cats and dogs.
Immunosuppressive drugs, also known as immunosuppressive agents, immunosuppressants and antirejection medications, are drugs that inhibit or prevent the activity of the immune system.
A pancreas transplant is an organ transplant that involves implanting a healthy pancreas into a person who usually has diabetes.
Mycophenolic acid is an immunosuppressant medication used to prevent rejection following organ transplantation and to treat autoimmune conditions such as Crohn's disease and lupus. Specifically it is used following kidney, heart, and liver transplantation. It can be given by mouth or by injection into a vein. It comes as mycophenolate sodium and mycophenolate mofetil.
Polyomaviridae is a family of viruses whose natural hosts are primarily mammals and birds. As of 2024, there are eight recognized genera. 14 species are known to infect humans, while others, such as Simian Virus 40, have been identified in humans to a lesser extent. Most of these viruses are very common and typically asymptomatic in most human populations studied. BK virus is associated with nephropathy in renal transplant and non-renal solid organ transplant patients, JC virus with progressive multifocal leukoencephalopathy, and Merkel cell virus with Merkel cell cancer.
Human polyomavirus 2, commonly referred to as the JC virus or John Cunningham virus, is a type of human polyomavirus. It was identified by electron microscopy in 1965 by ZuRhein and Chou, and by Silverman and Rubinstein, and later isolated in culture and named using the two initials of a patient, John Cunningham, with progressive multifocal leukoencephalopathy (PML). The virus causes PML and other diseases only in cases of immunodeficiency, as in AIDS or during treatment with immunosuppressive drugs.
Kidney transplant or renal transplant is the organ transplant of a kidney into a patient with end-stage kidney disease (ESRD). Kidney transplant is typically classified as deceased-donor or living-donor transplantation depending on the source of the donor organ. Living-donor kidney transplants are further characterized as genetically related (living-related) or non-related (living-unrelated) transplants, depending on whether a biological relationship exists between the donor and recipient. The first successful kidney transplant was performed in 1954 by a team including Joseph Murray, the recipient’s surgeon, and Hartwell Harrison, surgeon for the donor. Murray was awarded a Nobel Prize in Physiology or Medicine in 1990 for this and other work. In 2018, an estimated 95,479 kidney transplants were performed worldwide, 36% of which came from living donors.
A peripheral blood mononuclear cell (PBMC) is any peripheral blood cell having a round nucleus. These cells consist of lymphocytes and monocytes, whereas erythrocytes and platelets have no nuclei, and granulocytes have multi-lobed nuclei. In humans, lymphocytes make up the majority of the PBMC population, followed by monocytes, and only a small percentage of dendritic cells.
Leflunomide, sold under the brand name Arava among others, is an immunosuppressive disease-modifying antirheumatic drug (DMARD), used in active moderate-to-severe rheumatoid arthritis and psoriatic arthritis. It is a pyrimidine synthesis inhibitor that works by inhibiting dihydroorotate dehydrogenase.
Islet transplantation is the transplantation of isolated islets from a donor pancreas into another person. It is a treatment for type 1 diabetes. Once transplanted, the islets begin to produce insulin, actively regulating the level of glucose in the blood.
Glomerulosclerosis is the hardening of the glomeruli in the kidney. It is a general term to describe scarring of the kidneys' tiny blood vessels, the glomeruli, the functional units in the kidney that filter urea from the blood.
Decoy cells are virally infected epithelial cells that can be found in the urine. Decoy cells owe their name to their strong resemblance to cancer cells, and may as such confuse the diagnosis of either viral infection or urothelial malignancy. During 1950s, cytotechnologist Andrew Ricci observed cells mimicking cancer cells by they were not, in a group of persons working in some kinds of industries - they were referred to as “decoy cells”, analogous to “decoy ducks” used in hunting wild ducks, by Andrew Ricci, a cytotechnologist working renown cytopathologist Dr. Leopold G. Koss.
Merkel cell polyomavirus was first described in January 2008 in Pittsburgh, Pennsylvania. It was the first example of a human viral pathogen discovered using unbiased metagenomic next-generation sequencing with a technique called digital transcriptome subtraction. MCV is one of seven currently known human oncoviruses. It is suspected to cause the majority of cases of Merkel cell carcinoma, a rare but aggressive form of skin cancer. Approximately 80% of Merkel cell carcinoma (MCC) tumors have been found to be infected with MCV. MCV appears to be a common—if not universal—infection of older children and adults. It is found in respiratory secretions, suggesting that it might be transmitted via a respiratory route. However, it has also been found elsewhere, such as in shedded healthy skin and gastrointestinal tract tissues, thus its precise mode of transmission remains unknown. In addition, recent studies suggest that this virus may latently infect the human sera and peripheral blood mononuclear cells.
Trichodysplasia spinulosa is a rare cutaneous condition that has been described almost exclusively in immunocompromised patients, usually organ transplant recipients, on regimens of immunosuppressive drugs. As of early 2016, a total of 32 cases had been reported in the medical literature. Despite its rarity, TS is believed to be underdiagnosed, and the growing population of patients on immunosuppressive drug regimens suggests its incidence may rise. TS has been described as an emerging infectious disease.
Major capsid protein VP1 is a viral protein that is the main component of the polyomavirus capsid. VP1 monomers are generally around 350 amino acids long and are capable of self-assembly into an icosahedral structure consisting of 360 VP1 molecules organized into 72 pentamers. VP1 molecules possess a surface binding site that interacts with sialic acids attached to glycans, including some gangliosides, on the surfaces of cells to initiate the process of viral infection. The VP1 protein, along with capsid components VP2 and VP3, is expressed from the "late region" of the circular viral genome.
WU polyomavirus is a virus of the family Polyomaviridae. It was discovered in 2007 in samples of human respiratory secretions, originally from a child patient in Australia who presented with clinical signs of pneumonia and in whom other common respiratory viruses were not detected. Follow-up studies identified the presence of WU virus in respiratory secretion samples from patients in Australia and the United States, suggesting that, like other human polyomaviruses, WU virus is widely distributed.
Agnoprotein is a protein expressed by some members of the polyomavirus family from a gene called the agnogene. Polyomaviruses in which it occurs include two human polyomaviruses associated with disease, BK virus and JC virus, as well as the simian polyomavirus SV40.
Human polyomavirus 7 (HPyV7) is a virus of the polyomavirus family that infects human hosts. It was discovered in 2010 and is a common component of the skin flora in healthy adults. There is limited evidence from case reports linking the virus to a skin rash occurring in immunocompromised organ transplant recipients.
New Jersey polyomavirus is a virus of the polyomavirus family that infects human hosts. It was first identified in 2014 in a pancreatic transplant patient in New Jersey. It is the 13th and most recent human polyomavirus to be described.
