Common variable immunodeficiency (CVID) is an 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 foreign invaders, chronic lung disease, and inflammation and infection of the gastrointestinal tract. CVID affects males and females equally. The condition can be found in children or teens but is generally not diagnosed or recognized until adulthood. The average age of diagnosis is between 20 and 50. However, symptoms vary greatly between people. "Variable" refers to the heterogeneous clinical manifestations of this disorder, which include recurrent bacterial infections, increased risk for autoimmune disease and lymphoma, as well as gastrointestinal disease. CVID is a lifelong disease. Signs and symptoms
The symptoms of CVID vary between those affected. Its main features are hypogammaglobulinemia and recurrent infections. Hypogammaglobulinemia manifests as a significant decrease in the levels of IgG antibodies, usually alongside IgA antibodies; IgM antibody levels are also decreased in about half of those affected. Infections are a direct result of the low antibody levels in the circulation, which do not adequately protect them against pathogens. The microorganisms that most frequently cause infections in CVID are bacteria Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus. Pathogens less often isolated from those affected include Neisseria meningitidis, Pseudomonas aeruginosa, and Giardia lamblia. Infections mostly affect the respiratory tract (nose, sinuses, bronchi, lungs) and the ears; they can also occur at other sites, such as the eyes, skin, and gastrointestinal tract.
These infections respond to antibiotics but can recur upon discontinuation of antibiotics. Bronchiectasis can develop when severe recurrent pulmonary infections are left untreated. In addition to infections, people with CVID can develop complications. These include:

Autoimmune manifestations, e.g. pernicious anemia, autoimmune haemolytic anemia (AHA), idiopathic thrombocytopenic purpura (ITP), psoriasis, vitiligo, rheumatoid arthritis, primary hypothyroidism, atrophic gastritis. Autoimmunity is the main complication in people with CVID, appearing in some form in up to 50% of individuals;
Malignancies, particularly non-Hodgkins lymphoma and gastric carcinoma;
Enteropathy, which manifests with a blunting of intestinal villi and inflammation, and is usually accompanied by symptoms such as abdominal cramps, diarrhea, constipation, and in some cases malabsorption and weight loss. Symptoms of CVID enteropathy are similar to those of celiac disease, but do not respond to a gluten-free diet. Infectious causes must be excluded before a diagnosis of enteropathy can be made, as people with CVID are more susceptible to intestinal infections, e.g. by Giardia lamblia;
Lymphocytic infiltration of tissues, which can cause enlargement of lymph nodes (lymphadenopathy), of the spleen (plenomegaly) and of the liver (hepatomegaly), as well as the formation of granulomas. In the lung this is known as granulomatous–lymphocytic interstitial lung disease.Anxiety and depression can occur as a result of dealing with the other symptoms.CVID patients generally complain of severe fatigue.As with any antibody deficiency, the most common types of infections and illnesses involve the ears, sinuses, nose, and lungs. Common infections include:

Pneumonia
Ear infections
Sinusitis
Chronic coughing (lasting from a few weeks to many months)
Gastrointestinal infectionsGastrovascular infections or inflammation are very common for those with CVID.