"},"complications":{"wt":""},"onset":{"wt":""},"duration":{"wt":""},"types":{"wt":""},"causes":{"wt":""},"risks":{"wt":""},"diagnosis":{"wt":"[[Complete blood count]], [[Absolute neutrophil count|absolute neutrophil]] and [[lymphocyte count]]."},"differential":{"wt":"[[HIV]]."},"prevention":{"wt":""},"treatment":{"wt":"[[Immunoglobulin therapy]], [[antimicrobial prophylaxis]], and [[Hematopoietic stem cell transplantation]]."},"medication":{"wt":""},"prognosis":{"wt":""},"frequency":{"wt":"1:100,000 to 1:5000 live births."},"deaths":{"wt":""},"named after":{"wt":""}},"i":0}}]}" id="mwAg">Medical condition
Combined immunodeficiencies | |
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Other names | Combined immunity deficiency, CID |
Scanning electron micrograph of a human T lymphocyte (also called a T cell) from the immune system of a healthy donor. | |
Specialty | Hematology |
Symptoms | Diarrhea and sinus infections to opportunistic infections caused by mycobacteria, fungi, and vaccination reactions. [1] |
Diagnostic method | Complete blood count, absolute neutrophil and lymphocyte count. [1] |
Differential diagnosis | HIV. [1] |
Treatment | Immunoglobulin therapy, antimicrobial prophylaxis, and Hematopoietic stem cell transplantation. [1] |
Frequency | 1:100,000 to 1:5000 live births. [2] |
Combined immune deficiencies (CIDs) are a diverse group of inherited immune disorders characterized by impaired T lymphocyte development, function, or both, with variable B cell defects. The primary clinical manifestation of CID is infection susceptibility. [3] Clinical manifestations of combined immunodeficiencies vary greatly, ranging from diarrhea and sinus infections to opportunistic infections caused by mycobacteria, fungi, and vaccination reactions resulting in localized to systemic symptoms. [1]
Antibiotics and immunoglobulin replacement therapy are typically administered to patients as needed. Without hematopoietic cell or other transplantation aimed at correcting the underlying pathophysiological defect, prognosis is frequently poor due to T cell dysfunction. [4]
Patients with combined immune deficiencies typically exhibit recurrent gastrointestinal and respiratory tract infections, which can be attributed to a wide variety of bacteria. However, because of T cell dysfunction, patients frequently struggle to control viral infections, particularly Epstein-Barr virus, which is extremely sensitive to cytolytic T cell dysfunction. Deficits in viral infection control may contribute to an increased likelihood of malignancies, particularly EBV1 lymphoma. Other intracellular microbes, such as mycobacteria, can be difficult to control in CID patients, as can opportunistic or normally non-pathogenic infections caused by Pneumocystis jirovecii or Candida. [4]
When a clinical diagnosis of combined immunodeficiency is suspected, preliminary laboratory tests should be ordered. The patient's complete blood count (CBC) reveals immunological changes. The absolute neutrophil and lymphocyte count should be determined based on the patient's age. In all patients, HIV should be ruled out. Specific immunological parameters should be evaluated by measuring immunoglobulins, vaccinal response after 6 months of life, and flow cytometry measurement of larger leukocyte subtypes. [1]
Treatment for combined immunodeficiencies with defects in antibody production primarily consists of immunoglobulin replacement therapy. [1] Susceptibility to infections is an important feature of combined immunodeficiencies and influences patients' clinical evolution; as a result, antimicrobial prophylaxis is frequently used to prevent infections and their complications. [5] For patients with severe and lethal forms of inborn errors of immunity, hematopoietic stem-cell transplantation is currently the curative treatment of choice. [1]
Globally, the reported incidence of CIDs ranges from 1:100,000 to 1:5000 live births; however, due to patient mortality prior to diagnosis, misdiagnoses of patients exhibiting unusual clinical manifestations, and incomplete national registries recording CID incidence, this is thought to be an underestimate of the true incidence. There has been reported to be a diagnostic delay of a few days to several years between the age at which the disease first manifests and the diagnosis of CID. [2]
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, 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.
Adenosine deaminase deficiency is a metabolic disorder that causes immunodeficiency. It is caused by mutations in the ADA gene. It accounts for about 10–20% of all cases of autosomal recessive forms of severe combined immunodeficiency (SCID) after excluding disorders related to inbreeding.
ICF syndrome is a very rare autosomal recessive immune disorder.
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.
Common variable immunodeficiency (CVID) is an inborn immune disorder characterized by recurrent infections and low antibody levels, specifically in immunoglobulin (Ig) types IgG, IgM, and IgA. Symptoms generally include high susceptibility to pathogens, chronic lung disease, as well as inflammation and infection of the gastrointestinal tract.
X-linked severe combined immunodeficiency (X-SCID) is an immunodeficiency disorder in which the body produces very few T cells and NK cells.
Selective immunoglobulin A (IgA) deficiency (SIgAD) is a kind of immunodeficiency, a type of hypogammaglobulinemia. People with this deficiency lack immunoglobulin A (IgA), a type of antibody that protects against infections of the mucous membranes lining the mouth, airways, and digestive tract. It is defined as an undetectable serum IgA level in the presence of normal serum levels of IgG and IgM, in persons older than 4 years. It is the most common of the primary antibody deficiencies. Most such persons remain healthy throughout their lives and are never diagnosed.
Dysgammaglobulinemia is a type of immune disorder characterized by a reduction in some types of gamma globulins, resulting in heightened susceptibility to some infectious diseases where primary immunity is antibody based.
Hyper IgM syndrome is a rare primary immune deficiency disorders characterized by low or absent levels of serum IgG, IgA, IgE and normal or increased levels of serum IgM.
Hyper IgM syndrome type 2 is a rare disease. Unlike other hyper-IgM syndromes, type 2 patients identified thus far did not present with a history of opportunistic infections. One would expect opportunistic infections in any immunodeficiency syndrome. The responsible genetic lesion is in the AICDA gene found at 12p13.
Primary immunodeficiencies are disorders in which part of the body's immune system is missing or does not function normally. To be considered a primary immunodeficiency (PID), the immune deficiency must be inborn, not caused by secondary factors such as other disease, drug treatment, or environmental exposure to toxins. Most primary immunodeficiencies are genetic disorders; the majority are diagnosed in children under the age of one, although milder forms may not be recognized until adulthood. While there are over 430 recognized inborn errors of immunity (IEIs) as of 2019, the vast majority of which are PIDs, most are very rare. About 1 in 500 people in the United States are born with a primary immunodeficiency. Immune deficiencies can result in persistent or recurring infections, auto-inflammatory disorders, tumors, and disorders of various organs. There are currently limited treatments available for these conditions; most are specific to a particular type of PID. Research is currently evaluating the use of stem cell transplants (HSCT) and experimental gene therapies as avenues for treatment in limited subsets of PIDs.
Isolated primary immunoglobulin M deficiency is a poorly defined dysgammaglobulinemia characterized by decreased levels of IgM while levels of other immunoglobulins are normal. The immunodeficiency has been associated with some clinical disorders including recurrent infections, atopy, Bloom's syndrome, celiac disease, systemic lupus erythematosus and malignancy, but, surprisingly, SIgMD seems to also occur in asymptomatic individuals. High incidences of recurrent upper respiratory tract infections (77%), asthma (47%) and allergic rhinitis (36%) have also been reported. SIgMD seems to be a particularly rare antibody deficiency with a reported prevalence between 0.03% and 0.1%.
Humoral immune deficiencies are conditions which cause impairment of humoral immunity, which can lead to immunodeficiency. It can be mediated by insufficient number or function of B cells, the plasma cells they differentiate into, or the antibody secreted by the plasma cells. The most common such immunodeficiency is inherited selective IgA deficiency, occurring between 1 in 100 and 1 in 1000 persons, depending on population. They are associated with increased vulnerability to infection, but can be difficult to detect in the absence of infection.
Hyper-IgM syndrome type 4 is a form of Hyper IgM syndrome which is a defect in class switch recombination downstream of the AICDA gene that does not impair somatic hypermutation.
X-linked reticulate pigmentary disorder is a rare X-linked genetic condition in which males manifest multiple systemic symptoms and a reticulated mottled brown pigmentation of the skin, which, on biopsy, demonstrated dermal deposits of amyloid. Females usually only have linear streaks of hyperpigmentation.
Reticular dysgenesis (RD) is a rare, inherited autosomal recessive disease that results in immunodeficiency. Individuals with RD have mutations in both copies of the AK2 gene. Mutations in this gene lead to absence of AK2 protein. AK2 protein allows hematopoietic stem cells to differentiate and proliferate. Hematopoietic stem cells give rise to blood cells.
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.
An innate immune defect is a defect in the innate immune response that blunts the response to infection. These defects may occur in monocytes, neutrophils, natural killer cells, basophils, mast cells or complement proteins.
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