Common variable immunodeficiency: Difference between revisions
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'''Common variable immunodeficiency''' (CVID) is a group of 20-30 primary [[immunodeficiency|immunodeficiencies]] (PIDs) which have a common set of symptoms (including [[hypogammaglobulinemia]])<ref>{{Dorlands|i_03|12445103}}</ref> but with different underlying causes. |
'''Common variable immunodeficiency''' (CVID) is a group of 20-30 primary [[immunodeficiency|immunodeficiencies]] (PIDs) which have a common set of symptoms (including [[hypogammaglobulinemia]])<ref>{{Dorlands|i_03|12445103}}</ref> but with different underlying causes. |
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==Causes and types== |
==Causes and types== |
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CVID is believed to be a genetically determined primary immune defect; however, the underlying causes are different. The result of these defects is that the patient doesn't produce sufficient [[antibodies]] in response to exposure to [[pathogen]]s. As a result, the patient's [[immune system]] fails to protect them against common [[bacteria]]l and [[viral]] (and occasionally [[parasitic]] and [[protozoan]]) infections. The net result is that the patient is susceptible to illness. Both parts of the immune system (the [[Cell-mediated immunity|cellular]] and [[humoral]] system) are affected, hence its classification as a ''combined'' immunodeficiency. |
CVID is believed to be a genetically determined primary immune defect; however, the underlying causes are different. The result of these defects is that the patient doesn't produce sufficient [[antibodies]] in response to exposure to [[pathogen]]s. As a result, the patient's [[immune system]] fails to protect them against common [[bacteria]]l and [[viral]] (and occasionally [[parasitic]] and [[protozoan]]) infections. The net result is that the patient is susceptible to illness. Both parts of the immune system (the [[Cell-mediated immunity|cellular]] and [[humoral]] system) are affected, hence its classification as a ''combined'' immunodeficiency. |
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CVID appears to include a number of defects, some of which have been identified. For the majority, the genetic causes are still unknown. |
CVID appears to include a number of defects, some of which have been identified. For the majority, the genetic causes are still unknown. |
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[[CD278|ICOS]], [[TACI]] and [[CD19]] have been identified as candidates.<ref name="pmid18254984">{{cite journal |author=Salzer U, Neumann C, Thiel J, ''et al'' |title=Screening of functional and positional candidate genes in families with common variable immunodeficiency |journal=BMC Immunol. |volume=9 |issue=1 |pages=3 |year=2008 |pmid=18254984 |doi=10.1186/1471-2172-9-3 |url=http://www.biomedcentral.com/1471-2172/9/3}}</ref><ref name="pmid17173844">{{cite journal |author=Blanco-Quirós A, Solís-Sánchez P, Garrote-Adrados JA, Arranz-Sanz E |title=Common variable immunodeficiency. Old questions are getting clearer |journal=Allergol Immunopathol (Madr) |volume=34 |issue=6 |pages=263–75 |year=2006 |pmid=17173844 |doi= |url=http://db.doyma.es/cgi-bin/wdbcgi.exe/doyma/mrevista.pubmed_full?inctrl=05ZI0102&rev=105&vol=34&num=6&pag=263}}</ref> |
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It is possible that environmental agents provoke the immune defect, due to genetic predisposition, but this has not been clarified. |
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==Related conditions== |
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See also [[X-linked agammaglobulinemia]], a similar disorder, better characterised than CVID. |
See also [[X-linked agammaglobulinemia]], a similar disorder, better characterised than CVID. |
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Hypogammaglobulinemia (CVID) and [[X-linked agammaglobulinemia]] (XLA) are often intermixed by physicians, as their clinical conditions and treatment are almost identical. |
Hypogammaglobulinemia (CVID) and [[X-linked agammaglobulinemia]] (XLA) are often intermixed by physicians, as their clinical conditions and treatment are almost identical. |
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Revision as of 09:24, 1 March 2008
| Common variable immunodeficiency | |
|---|---|
| Specialty | Immunology  |
Common variable immunodeficiency (CVID) is a group of 20-30 primary immunodeficiencies (PIDs) which have a common set of symptoms (including hypogammaglobulinemia)[1] but with different underlying causes.
Causes and types
CVID is believed to be a genetically determined primary immune defect; however, the underlying causes are different. The result of these defects is that the patient doesn't produce sufficient antibodies in response to exposure to pathogens. As a result, the patient's immune system fails to protect them against common bacterial and viral (and occasionally parasitic and protozoan) infections. The net result is that the patient is susceptible to illness. Both parts of the immune system (the cellular and humoral system) are affected, hence its classification as a combined immunodeficiency.
CVID appears to include a number of defects, some of which have been identified. For the majority, the genetic causes are still unknown.
ICOS, TACI and CD19 have been identified as candidates.[2][3]
It is possible that environmental agents provoke the immune defect, due to genetic predisposition, but this has not been clarified.
Related conditions
See also X-linked agammaglobulinemia, a similar disorder, better characterised than CVID. Hypogammaglobulinemia (CVID) and X-linked agammaglobulinemia (XLA) are often intermixed by physicians, as their clinical conditions and treatment are almost identical.
Symptomology
Symptoms of CVID are:
- hypogammaglobulinemia, or low levels of immunoglobulin G (IgG), immunoglobulin A (IgA) and/or immunoglobulin M (IgM).
- lack of normal levels of antibody in the serum is part of the diagnosis
- polyarthritis, or joint pain, spread across most joints, but specifically fingers, wrists, elbows, toes, ankles and knees
- chronic infections. (most common symptom) Specifically: upper respiratory tract infection - e.g. bronchitis, sinusitis which respond to antibiotics but return or recur.
- Viral infections that usually respond to antivirals, sinusitis, tonsilitis, epiglottitis, dermatological abscesses/boils (often, but not exclusively, facial and axillary), pneumonia, bronchitis, pleurisy, stomach/intestinal infections, colds, influenza, shingles, conjunctivitis
- Tiredness
- Chronic swelling of the lymph glands
- Enlarged spleen
- atrophic gastritis with pernicious anemia
- nodular lymphoid hyperplasia of the intestine. This finding can be mistaken for intestinal lymphoma
- bacterial overgrowth of the intestine.
- increased intestinal permeability (i.e. leaky gut)
- villous atrophy in the small intestine, which can resemble coeliac disease and cause diarrhoea and malabsorption
- chronic diarrhoea (often arises as a result of "minor" intestinal infections, including protozoan and parasitic infections)
- increased incidence of inflammatory bowel disease
- bronchiectasis (lung tissue damage as a result of repeated chest infections) leading to shortness of breath
- poor titer levels in response to vaccination. Responsiveness may be tested after administration of polysaccharide and non-polysaccharide coated pathogens (e.g. streptococci and tetanus respectively)
- children may show a "failure to thrive" - they may be underweight and underdeveloped compared with "normal" peers
- patients may lose weight
Diagnosis is often delayed; and diagnosis is often made in the second or third decade of life after referral to an immunologist.
As with several other immune cell disorders, CVID may predispose to lymphoma or possibly stomach cancer.[4] There also appears to be a predilection for autoimmune diseases, with a risk of up to 25%. Autoimmune destruction of platelets or red blood cells are the commonest of these.
Treatment
Treatment usually consists of immunoglobulin therapy, which is an injection of human antibodies harvested from blood donations: intravenous immunoglobulin (IVIG, most common treatment), subcutaneous immunoglobulin G (SCIG, relatively new therapy) or intramuscular immunglobulin (IMIG, less effective, painful). This is not a cure, but it strengthens immunity by ensuring that the patient has "normal" levels of antibodies, which helps to prevent recurrent upper respiratory infections. IG therapy can't be used if the patient has anti-IgA antibodies but in this case, products low in IgA can be used; subcutaneous delivery also is a means of permitting such patients to have adequate antibody replacement.
Some CVID patients may experience reactions to IG therapies; reactions may include:
- anaphylactic shock (very rare)
- hives (rare)
- difficulty breathing
- headache (relatively common, may be relieved by an antihistamine, paracetamol/acetaminophen, or an anti-inflammatory (naproxen, advil, aspirin)
- nausea (common)
- fever (common)
- aseptic meningitis (rare)
- severe fatigue
- muscle aches and pain, or joint pain
- thrombotic events (rare)
Patients should not receive therapy if they are fighting an active infection as this increases the risk of reaction. Also, patients changing from one brand of product to another may be at higher risk of reaction for the first couple of treatments on the new brand.
Reactions can be minimised by taking an antihistamine and/or hydrocortisone and some paracetamol/acetaminophen/anti-inflammatory (naproxen, advil, aspirin) prior to treatment; patients should also be thoroughly hydrated and continue to drink water before, after and during treatment (if possible).
Research
Research is currently focussing on genetic analysis, and in differentiating between the various different disorders in order to allow a cure to be developed. Cures are likely to be genetic in nature, repairing faulty genes and allowing the individual to start producing antibodies. Funding for research in the US is provided by the National Institutes of Health. Key research in the UK is funded by the Primary Immunodeficiency Association (PiA), and funding is raised through the annual Jeans for Genes campaign.
Epidemiology
CVID has an estimated prevalence is about 1:25,000 to 1:50,000. The typical patient is between 20 and 40, and males and females are equally affected. About 20% of patients are diagnosed in childhood.
History
Janeway et al (1953) is generally credited with the description of the first case of CVID.[5]
References
- ^ "12445103" at Dorland's Medical Dictionary
- ^ Salzer U, Neumann C, Thiel J; et al. (2008). "Screening of functional and positional candidate genes in families with common variable immunodeficiency". BMC Immunol. 9 (1): 3. doi:10.1186/1471-2172-9-3. PMID 18254984.
{{cite journal}}: Explicit use of et al. in:|author=(help)CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - ^ Blanco-Quirós A, Solís-Sánchez P, Garrote-Adrados JA, Arranz-Sanz E (2006). "Common variable immunodeficiency. Old questions are getting clearer". Allergol Immunopathol (Madr). 34 (6): 263–75. PMID 17173844.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Mellemkjaer L, Hammarstrom L, Andersen V; et al. (2002). "Cancer risk among patients with IgA deficiency or common variable immunodeficiency and their relatives: a combined Danish and Swedish study". Clin. Exp. Immunol. 130 (3): 495–500. PMID 12452841.
{{cite journal}}: Explicit use of et al. in:|author=(help)CS1 maint: multiple names: authors list (link) - ^ Janeway CA, Apt L, Gitlin D. Agammaglobulinemia. Trans Assoc Am Physicians 1953;66:200-2. PMID 13136263
External links
- Primary Immunodeficiency Association (UK)
- Immune Deficiency Foundation (US)
- Michigan Immunodeficiency Foundation (US)
- Immune Deficiencies Foundation of Australia
- Immune Deficiencies Foundation of New Zealand
- IPOPI (International Patient Organisation for Patients with Primary Immunodeficiency)
- Canadian Immunodeficiencies Patient Organization (Canada)
- Dutch Patient Organisation for Primary Immunodeficiencies (SAS)