Primary immune deficiency (PID) refers to a group of disorders caused by genetic defects that impair the immune system's ability to function properly. Individuals with PID are more susceptible to infections, as their bodies struggle to fight off bacteria, viruses, and other pathogens. These conditions can affect various components of the immune system, including B cells, T cells, and antibodies. Symptoms of primary immune deficiency can vary widely, but common signs include frequent infections, delayed recovery from illnesses, and unusual infections that are rare in healthy individuals. Diagnosis often involves blood tests to assess immune function, and treatment may include immunoglobulin therapy or antibiotics to help manage infections and improve immune response.