Final answer:
Primary immunodeficiencies are inherited conditions due to genetic defects, leading to a compromised immune system and increased susceptibility to infections. Secondary immunodeficiencies are acquired after birth and can often be reversed if the cause is resolved; one example is HIV/AIDS. Both types lead to a higher risk of infections and potentially other complications.
Step-by-step explanation:
Primary and Secondary Immunodeficiencies
Immunodeficiencies can be classified into two types: primary immunodeficiencies and secondary immunodeficiencies. Primary immunodeficiencies are inherited conditions caused by genetic abnormalities leading to defects in the immune system's ability to fight off infections. These disorders are typically diagnosed in infancy or early childhood due to recurrent or overwhelming infections. Examples include chronic granulomatous disease, X-linked agammaglobulinemia, selective IgA deficiency, and severe combined immunodeficiency disease (SCID).
In contrast, secondary immunodeficiencies are acquired after birth due to environmental factors such as infections, malnutrition, chemical exposures, or certain medical treatments. These are often reversible if the underlying cause is resolved. An example of a secondary immunodeficiency is what occurs in patients with HIV, where the virus infects and destroys helper T cells leading to acquired immunodeficiency syndrome (AIDS).
While primary immunodeficiencies are less common than secondary ones, they are generally more severe due to their innate nature. Secondary immunodeficiencies like those caused by HIV are more prevalent globally. Both types result in an elevated susceptibility to infections and potentially other complications such as cancer.