Common Variable Immunodeficiency (CVID)

Common Variable Immunodeficiency (CVID) is a type of primary immunodeficiency disorder characterized by impaired antibody production, leading to recurrent infections and other complications.

Definition and Prevalence

CVID is a heterogeneous group of disorders that affect the immune system's ability to produce antibodies, also known as immunoglobulins. It is estimated to affect approximately 1 in 50,000 to 1 in 100,000 individuals worldwide.

Causes and Risk Factors

The exact cause of CVID is unknown, but it is believed to result from a combination of genetic and environmental factors. Some individuals with CVID may have a family history of the condition, suggesting a possible genetic component. Other potential risk factors include:

• Genetic mutations affecting immune system function
• Familial predisposition
• Autoimmune disorders, such as rheumatoid arthritis or lupus
• Certain infections, such as hepatitis C or HIV

Symptoms and Clinical Presentation

Individuals with CVID often experience recurrent infections, particularly of the respiratory and gastrointestinal tracts. Common symptoms include:

• Recurrent sinusitis or bronchitis
• Pneumonia or other respiratory infections
• Gastrointestinal infections, such as diarrhea or abdominal pain
• Fatigue or malaise
• Weight loss or failure to thrive

Diagnosis and Diagnostic Criteria

Diagnosing CVID can be challenging due to its heterogeneous nature and variable presentation. The following criteria are commonly used to diagnose CVID:

• Low levels of immunoglobulins (IgG, IgA, and/or IgM) in the blood
• Poor response to vaccinations or infections
• Recurrent infections, particularly of the respiratory and gastrointestinal tracts
• Exclusion of other underlying conditions that may cause similar symptoms

Treatment and Management

Treatment for CVID typically involves:

• Immunoglobulin replacement therapy (IGRT) to replace deficient antibodies
• Antibiotics or antiviral medications to treat infections
• Vaccinations to prevent infections, although response may be impaired
• Lifestyle modifications, such as avoiding close contact with individuals who are sick and practicing good hygiene

Complications and Prognosis

If left untreated or undertreated, CVID can lead to various complications, including:

• Chronic lung disease or bronchiectasis
• Gastrointestinal disorders, such as malabsorption or inflammatory bowel disease
• Autoimmune disorders, such as rheumatoid arthritis or lupus
• Cancer, particularly lymphoma

With proper treatment and management, individuals with CVID can lead active and relatively normal lives. However, the condition requires ongoing medical care and monitoring to prevent complications and optimize quality of life.