Final answer:
The immune system is most commonly affected in patients with primary immunodeficiencies, leading to increased susceptibility to infections and a wide array of symptoms. These disorders are often inherited and can be fatal without proper treatment. Management of these conditions depends on the specific type and severity of the immunodeficiency.
Step-by-step explanation:
The system most commonly affected in patients with primary immunodeficiencies is the immune system. Individuals with these conditions have an increased susceptibility to infections due to inherited defects in their immune response capabilities. These disorders can result in a wide array of symptoms, often involving recurrent infections, and can be fatal if left untreated.
Primary immunodeficiency diseases are a group of disorders arising from defects in immune system development and/or function. They are generally classified based on the part of the immune system that is affected: B cells, T cells, phagocytes, or complement system. Some well-known primary immunodeficiencies include Severe Combined Immunodeficiency (SCID), Chronic Granulomatous Disease, and X-linked Agammaglobulinemia.
At the global level, the most common cause of immunodeficiency is malnutrition, while in developed countries, most cases are due to genetic abnormalities. Treatments can range from stem cell transplantation to enzyme replacement and gene therapy depending on the type and severity of the immunodeficiency.