Signs of a gastrovascular infection include abdominal pain, nausea, bloating, vomiting, diarrhea, and weight loss. Many individuals with CVID have an impaired ability to absorb nutrients, including vitamins, proteins, minerals, fats, and sugar within the digestive tract.Due to changes in development in B cells, some individuals with CVID have accumulations of lymphocytes in lymphoid tissues. This can cause mild to severely swollen lymph nodes or inflammation of the spleen. In addition, a certain percentage of individuals with CVID are more susceptible to developing certain forms of cancer, more so than those without the condition. The two most common cancers in common variable immunodeficiency patients include lymphoma and certain stomach cancers. The risk for these given cancers is almost fifty times greater in common variable immunodeficiency patients than those without. People with common variable immunodeficiency have trouble fighting off infections due to the lack of antibodies produced which normally resist invading microbes. Due to impaired antibody development vaccines are not effective. Recurring bacterial infections are generally found in the upper and lower areas of the respiratory tract. Many who have a recurring lung infection, report developing, chronic lung diseases, and potentially life-threatening complications later in life. Causes
The cause of CVID is poorly understood. A likely cause are Deletions in genes that encode cell surface proteins and cytokine receptors, such as CD19, CD20, CD21, and CD80. Additionally, the disease is defined by T cell defects, namely reduced proliferative capacity. The condition is hard to diagnose, taking on average 6–7 years after onset. CVID is a primary immunodeficiency.
The underlying causes of CVID are largely obscure. Genetic mutations can be identified as the cause of disease in about 10% of people, while familial inheritance accounts for 10–25% of cases. Rather than arising from a single genetic mutation, CVID seems to result from variety of mutations that all contribute to a failure in antibody production. Mutations in the genes encoding ICOS, TACI, CD19, CD20, CD21, CD80 and BAFFR have been identified as causative of CVID. Susceptibility to CVID may also be linked to the major histocompatibility complex (MHC) of the genome, particularly to DR-DQ haplotypes. A mutation in the NFKB2 gene has recently been shown to cause CVID-like symptoms in a murine model. The frequency of this NFKB2 mutation in the CVID population is, however, yet to be established. Diagnosis
According to a European registry study, the mean age at onset of symptoms was 26.3 years old. As per the criteria laid out by ESID (European Society for Immunodeficiencies) and PAGID (Pan-American Group for Immunodeficiency), CVID is diagnosed if:
the person presents with a marked decrease of serum IgG levels (<4.5 g/L) and a marked decrease below the lower limit of normal for age in at least one of the isotypes IgM or IgA;
the person is four years of age or older;
the person lacks antibody immune response to protein antigens or immunization.Diagnosis is chiefly by exclusion, i.e. alternative causes of hypogammaglobulinemia, such as X-linked agammaglobulinemia, must be excluded before a diagnosis of CVID can be made.