Common Variable Immunodeficiency Support Group

CVID's underlying causes are different, but the result of these are 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 protozoal) infections. The net result is that the patient is prone to illness. Both parts of the immune system (the cellular and humoral system) are affected, hence its classification as a combined immunodeficiency.

Because CVID is a catch-all diagnosis, which encompasses a number of as-yet undifferentiated disorders, the cause of each specific disorder is different so one can't identify a single common theme. Some cases appear to be genetic, similarly to severe combined immunodeficiency (SCID), some appear to be environmental in some way, some may be pathogenic (with Epstein-Barr virus implicated by some informal research). Most of the diagnoses are probably a combination of genetic predisposition along with a pathogenic or envirogenic trigger.

Symptoms of CVID are:

• hypogammglobulinaemia, or low levels of immunoglobulin G (IgG)
• many patients have low levels of immunoglobulin A (IgA) and immunoglobulin M (IgM)
• polyarthritis, or joint pain, spread across most joints, but specifically fingers, wrists, elbows, toes, ankles and knees
• repeated incidence of infections which respond to antibiotics or antivirals, specifically: upper respiratory tract infections (URTIs), sinusitis, tonsilitis, epiglottitis, dermatological abscesses/boils (often, but not exclusively, facial and axillary), pneumonia, bronchitis, pleurisy, stomach/intestinal infections, colds, influenza, shingles, conjunctivitis
• Tiredness
• atrophic gastritis with pernicious anemia
• nodular lymphoid hyperplasia of the intestine. This finding can be mistaken for intestinal lymphoma
• bacterial overgrowth of the villous atrophy in the small intestine, which can resemble coeliac disease and cause diarrhoea and malabsorption
• diarrhoea (often arises as a result of "minor" intestinal infections, including protozoal 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 normally takes in excess of two years, and diagnosis is often made in the second or third decade of life after referral to an immunologist.

Treatment usually consists of immunoglobulin therapy, either intravenous immunoglobulin (IVIG), subcutaneous immunoglobulin G (SCIG) or (less frequently) intramuscular immunglobulin (IMIG). This is not a cure, but does help to ensure the patient has "normal" levels of antibodies, which helps to prevent recurrent infections. IG therapy may be inappropriate if the patient has anti-IgA antibodies.