A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include T cells, B cells, and Innate lymphoid cells (ILCs), of which natural killer cells are an important subtype. They are the main type of cell found in lymph, which prompted the name "lymphocyte". Lymphocytes make up between 18% and 42% of circulating white blood cells.
Immunodeficiency, also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that affect the patient's immune system. Examples of these extrinsic factors include HIV infection and environmental factors, such as nutrition. Immunocompromisation may also be due to genetic diseases/flaws such as SCID.
Chédiak–Higashi syndrome (CHS) is a rare autosomal recessive disorder that arises from a mutation of a lysosomal trafficking regulator protein, which leads to a decrease in phagocytosis. The decrease in phagocytosis results in recurrent pyogenic infections, albinism, and peripheral neuropathy.
Hypogammaglobulinemia is an immune system disorder in which not enough gamma globulins are produced in the blood. This results in a lower antibody count, which impairs the immune system, increasing risk of infection. Hypogammaglobulinemia may result from a variety of primary genetic immune system defects, such as common variable immunodeficiency, or it may be caused by secondary effects such as medication, blood cancer, or poor nutrition, or loss of gamma globulins in urine, as in nonselective glomerular proteinuria. Patients with hypogammaglobulinemia have reduced immune function; important considerations include avoiding use of live vaccines, and take precautionary measures when traveling to regions with endemic disease or poor sanitation such as receiving immunizations, taking antibiotics abroad, drinking only safe or boiled water, arranging appropriate medical cover in advance of travel, and ensuring continuation of any immunoglobulin infusions needed.
Hyperimmunoglobulinemia E syndrome (HIES), of which the autosomal dominant form is called Job's syndrome or Buckley syndrome, is a heterogeneous group of immune disorders. Job's is also very rare at about 300 cases currently in the literature.
Griscelli syndrome is a rare autosomal recessive disorder characterized by albinism (hypopigmentation) with immunodeficiency, that usually causes death by early childhood. Researchers have developed three different classifications of the form of disorder, characterised by different signs and symptoms. Type 1 Griscelli Syndrome is assosciated with severe brain function issues along with distinctive discolouring of the hair and skin. Type 2 Griscelli Syndrome have immune system abnormalities in addition to hypopigmentation of skin and hair. Finally, Type 3 is seen as those only affected by hypopigmentation of the skin and hair. This type is not associated with immune deficiencies or neurological abnormalities.
Fever of unknown origin (FUO) refers to a condition in which the patient has an elevated temperature (fever) but, despite investigations by one or more qualified physicians, no explanation is found.
Dedicator of cytokinesis protein 8 (Dock8) is a large protein encoded in the human by the DOCK8 gene, involved in intracellular signalling networks. It is a member of the DOCK-C subfamily of the DOCK family of guanine nucleotide exchange factors (GEFs) which function as activators of small G-proteins.
Lupus, technically known as systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Common symptoms include painful and swollen joints, fever, chest pain, hair loss, mouth ulcers, swollen lymph nodes, feeling tired, and a red rash which is most commonly on the face. Often there are periods of illness, called flares, and periods of remission during which there are few symptoms.
Mendelian susceptibility to mycobacterial disease (MSMD) is a rare genetic disease. It is a primary immunodeficiency featured by molecular defects in IL12/IFNγ dependent signalling pathway, leading to increased susceptibility to local or disseminated infections by environmental mycobacteria, Mycobacterium bovis Bacille Calmette-Guerin strain, nontyphoidal and typhoidal Salmonella serotypes.
DNA polymerase alpha catalytic subunit is an enzyme that in humans is encoded by the POLA1 gene.
DOCK8 deficiency, also called DOCK8 immunodeficiency syndrome, is the autosomal recessive form of hyperimmunoglobulin E syndrome, a genetic disorder characterized by elevated immunoglobulin E levels, eosinophilia, and recurrent infections with staphylococcus and viruses. It is caused by a mutation in the DOCK8 gene.
Oral manifestations of systematic disease are signs and symptoms of disease occurring elsewhere in the body detected in the oral cavity and oral secretions. High blood sugar can be detected by sampling saliva. Saliva sampling may be a non-invasive way to detect changes in the gut microbiome and changes in systemic disease. Another example is tertiary syphilis, where changes to teeth can occur. Syphilis infection can be associated with longitudinal furrows of the tongue.
GATA2 deficiency is a grouping of several disorders caused by common defect, namely, familial or sporadic inactivating mutations in one of the two parental GATA2 genes. Being the gene haploinsufficient, mutations that cause a reduction in the cellular levels of the gene's product, GATA2, are autosomal dominant. The GATA2 protein is a transcription factor critical for the embryonic development, maintenance, and functionality of blood-forming, lymphatic-forming, and other tissue-forming stem cells. In consequence of these mutations, cellular levels of GATA2 are deficient and individuals develop over time hematological, immunological, lymphatic, or other presentations that may begin as apparently benign abnormalities but commonly progress to severe organ failure, opportunistic infections, virus infection-induced cancers, the myelodysplastic syndrome, and/or leukemia. GATA2 deficiency is a life-threatening and precancerous condition.
Deficiency of Adenosine deaminase 2 (DADA2) is a monogenic disease associated with systemic inflammation and vasculopathy that affects a wide variety of organs in different patients. As a result, it is hard to characterize a patient with this disorder. Manifestations of the disease include but are not limited to recurrent fever, livedoid rash, various cytopenias, stroke, immunodeficiency, and bone marrow failure. Symptoms often onset during early childhood, but some cases have been discovered as late as 65 years old.
Epstein–Barr virus–associated lymphoproliferative diseases are a group of disorders in which one or more types of lymphoid cells, i.e. B cells, T cells, NK cells, and histiocytic-dendritic cells, are infected with the Epstein–Barr virus (EBV). This causes the infected cells to divide excessively, and is associated with the development of various non-cancerous, pre-cancerous, and cancerous lymphoproliferative disorders (LPDs). These LPDs include the well-known disorder occurring during the initial infection with the EBV, infectious mononucleosis, and the large number of subsequent disorders that may occur thereafter. The virus is usually involved in the development and/or progression of these LPDs although in some cases it may be an "innocent" bystander, i.e. present in, but not contributing to, the disease.
Mosquito bite allergies, also termed hypersensitivity to mosquito bites, are excessive reactions of varying severity to mosquito bites. They are allergic hypersensitivity reactions caused by the non-toxic allergenic proteins contained in the saliva injected by a female mosquito at the time it takes its blood meal, and are not caused by any toxin or pathogen. By general agreement, mosquito bite allergies do not include the ordinary wheal and flare responses to these bites although these reactions are also allergic in nature. Ordinary mosquito bite allergies are nonetheless detailed here because they are the best understood reactions to mosquito bites and provide a basis for describing what is understood about them.
Autoinflammatory diseases (AIDs) are a group of rare disorders caused by dysfunction of the innate immune system. They are characterized by periodic or chronic systemic inflammation, usually without the involvement of adaptive immunity.
Hypohidrotic/anhidrotic ectodermal dysplasia with immune deficiency is a rare genetic condition characterized by a combination of the features of ectodermal dysplasia alongside immunodeficiency.
