Granulomatosis with Polyangiitis (GPA) is a rare autoimmune disease that causes inflammation of blood vessels, leading to damage in various organs, particularly the lungs, kidneys, and sinuses. It is characterized by the formation of granulomas, which are clusters of immune cells that form in response to inflammation. Symptoms may include persistent sinusitis, coughing, and kidney problems. The exact cause of GPA is unknown, but it is believed to involve a combination of genetic and environmental factors. Diagnosis typically involves blood tests, imaging studies, and sometimes a biopsy of affected tissue. Treatment often includes medications to suppress the immune system, such as corticosteroids and immunosuppressants.