cells/mm3; this particular phenotype of CVID has been named LOCID (Late Onset Combined Immunodeficiency), and has a poorer prognosis than classical CVID. Types The following types of CVID have been identified, and correspond to mutations in different gene segments. Treatment Treatment options are limited, and usually include lifelong immunoglobulin replacement therapy. This therapy is thought to help reduce bacterial infections. This treatment alone is not wholly effective, and many people still experience other symptoms such as lung disease and noninfectious inflammatory symptoms. This treatment replenishes Ig subtypes that the person lacks and is given at frequent intervals for life, and is thought to help reduce bacterial infections and boost immune function. Before therapy begins, plasma donations are tested for known blood-borne pathogens, then pooled and processed to obtain concentrated IgG samples. Infusions can be administered in three different forms: intravenously (IVIg), subcutaneously (SCIg), and intramuscularly (IMIg). The administration of intravenous immunoglobulins requires the insertion of a cannula or needle in a vein, usually in the arms or hands. Because highly concentrated product is used, IVIg infusions take place every 3 to 4 weeks. Subcutaneous infusions slowly release the Ig serum underneath the skin, again through a needle, and takes place every week. Intramuscular infusions are no longer widely used, as they can be painful and are more likely to cause reactions. People often experience adverse side effects to immunoglobulin infusions, including: swelling at the insertion site (common in SCIG) chills headache nausea (common in IVIG) fatigue (common in IVIG) muscle aches and pain, or joint pain fever (common in IVIG and rare in SCIG) hives (rare) thrombotic events (rare) aseptic meningitis (rare, more common in people with SLE) anaphylactic shock (very rare) In addition to Ig replacement therapy, treatment may also involve immune suppressants, to control autoimmune symptoms of the disease, and high dose steroids like corticosteroids. In some cases, antibiotics are used to fight chronic lung disease resulting from CVID. The outlook for people varies greatly depending on their level of lung and other organ damage prior to diagnosis and treatment. Epidemiology CVID has an estimated prevalence of about 1:50,000 in Caucasians. The disease seems to be less prevalent amongst Asians and African-Americans. Males and females are equally affected; however, among children, boys predominate. A recent study of people in Europe with primary immunodeficiencies found that 30% had CVID, as opposed to a different immunodeficiency. 10–25% of people inherited