MedGen

The occurrence of an immune reaction against the organism's own cells or tissues. [from HPO]

A type of primary immune deficiency that is characterized by a more severe defect in both the T- and B-lymphocyte systems. [from HPO]

A rare disease that occurs after allogeneic hematopoietic stem cell transplant and is a reaction of donor immune cells against host tissues. Activated donor T cells damage host epithelial cells after an inflammatory cascade that begins with the preparative regimen. [from ORDO]

Idiopathic inflammatory myopathy is a group of disorders characterized by inflammation of the muscles used for movement (skeletal muscles). Idiopathic inflammatory myopathy usually appears in adults between ages 40 and 60 or in children between ages 5 and 15, though it can occur at any age.

The primary symptom of idiopathic inflammatory myopathy is muscle weakness, which develops gradually over a period of weeks to months or even years. Other symptoms include joint pain and general tiredness (fatigue).

In sporadic inclusion body myositis, the muscles most affected are those of the wrists and fingers and the front of the thigh. Affected individuals may frequently stumble while walking and find it difficult to grasp items. As in dermatomyositis and polymyositis, swallowing can be difficult.

There are several forms of idiopathic inflammatory myopathy, including polymyositis, dermatomyositis, and sporadic inclusion body myositis.

Polymyositis and dermatomyositis involve weakness of the muscles closest to the center of the body (proximal muscles), such as the muscles of the hips and thighs, upper arms, and neck. People with these forms of idiopathic inflammatory myopathy may find it difficult to climb stairs, get up from a seated position, or lift items above their head. In some cases, muscle weakness may make swallowing or breathing difficult.

Polymyositis and dermatomyositis have similar symptoms, but dermatomyositis is distinguished by a reddish or purplish rash on the eyelids, elbows, knees, or knuckles. Sometimes, abnormal calcium deposits form hard, painful bumps under the skin (calcinosis). [from MedlinePlus Genetics]

Myasthenia gravis is an autoimmune disease in which antibodies bind to acetylcholine receptors or to functionally related molecules in the postsynaptic membrane at the neuromuscular junction. The antibodies induce weakness of skeletal muscles, which is the sole disease manifestation. The weakness can be generalized or localized, is more proximal than distal, and nearly always includes eye muscles, with diplopia and ptosis. The pattern of involvement is usually symmetric, apart from the eye involvement, which is often markedly asymmetric and involves several eye muscles. The weakness typically increases with exercise and repetitive muscle use (fatigue) and varies over the course of a day and from day to day, often with nearly normal muscle strength in the morning (summary by Gilhus, 2016). [from OMIM]

A type of weakness that occurs after a muscle group is used and lessens if the muscle group has some rest. That is, there is diminution of strength with repetitive muscle actions. [from HPO]

Immunodeficiency disease that arises independent of another pathologic process, disease, or injury. [from NCI]

A disorder characterized by the degeneration of the nervous system due to autoimmunity. Representative examples include multiple sclerosis, Guillain-Barre syndrome, and myasthenia gravis. [from NCI]

Conditions characterized by impaired transmission of impulses at the neuromuscular junction. This may result from disorders that affect receptor function, pre- or postsynaptic membrane function, or acetylcholinesterase activity. The majority of diseases in this category are associated with autoimmune, toxic, or inherited conditions. [from MONDO]

An infectious process affecting the skeletal muscles. It can be caused by viruses (including HIV), bacteria, fungi, and parasites. Symptoms include muscle weakness and muscle pain. [from NCI]

A classification for rare disorders of diverse organ systems (endocrine, neuromuscular, gastrointestinal, renal, dermatologic, rheumatologic, hematologic) that are affected by substances secreted by a distant neoplasm but not by the action of the neoplasm itself metastasizing to that organ or tissue. Less than 1 % of neoplasms are associated with these syndromes. An immune-mediated response to neoplasm-elaborated proteins may be the cause of these syndromes. Additionally, their manifestation may signal the presence of an occult neoplasm, potentially at an earlier stage of disease thereby leading to a better clinical outcome. Constitutional signs may include fever, night sweats, anorexia and cachexia. Clinical course is usually progressive. Prognosis is variable depending on the effective treatment of the underlying neoplasm. [from NCI]