Anti-glomerular basement membrane antibody

Anti-glomerular basement membrane antibody (anti-GBM antibody) disease, also known as Goodpasture's syndrome or Goodpasture disease, is a rare autoimmune disorder characterized by the presence of harmful antibodies that attack the glomerular basement membrane (GBM) in the kidneys and often the lungs. This leads to glomerulonephritis, a type of nephritis affecting the glomeruli, and can also cause pulmonary hemorrhage, a bleeding disorder in the lungs.

Etiology and Pathogenesis

The exact cause of anti-GBM antibody disease is not fully understood, but it involves the production of autoantibodies that target the Type IV collagen found in the GBM of the kidneys and the alveolar basement membranes in the lungs. This autoimmune response leads to inflammation and damage, impairing the function of these organs. Environmental factors, such as exposure to certain hydrocarbons or tobacco smoke, and genetic predisposition may play roles in the development of the disease.

Clinical Presentation

Patients with anti-GBM antibody disease may present with a range of symptoms, including:

• Hematuria (blood in urine)
• Proteinuria (protein in urine)
• Reduced kidney function
• Fatigue
• Difficulty breathing
• Coughing up blood (in cases where the lungs are involved)

Diagnosis

Diagnosis of anti-GBM antibody disease involves a combination of clinical evaluation, laboratory tests, and imaging studies. Key diagnostic tests include:

• Anti-GBM antibody testing through blood serum analysis
• Renal biopsy to assess the extent of kidney damage and the presence of characteristic linear deposits of IgG along the GBM
• Chest X-rays or CT scans to detect pulmonary involvement

Treatment

Treatment for anti-GBM antibody disease aims to remove the circulating antibodies and to suppress the immune system's attack on the body. Therapeutic strategies include:

• Plasmapheresis to remove anti-GBM antibodies from the blood
• High-dose corticosteroids to reduce inflammation
• Immunosuppressive drugs, such as cyclophosphamide, to suppress the immune response
• Supportive care for kidney failure, including dialysis if necessary

Prognosis

The prognosis for patients with anti-GBM antibody disease varies. Early diagnosis and treatment can improve outcomes, but the disease can progress rapidly to kidney failure and death if not treated promptly. Long-term outcomes depend on the extent of kidney damage at the time of diagnosis and the response to treatment.

Epidemiology

Anti-GBM antibody disease is rare, with an estimated incidence of one case per million people per year. It can occur at any age but is most commonly diagnosed in individuals in their 20s and 30s. There is no significant gender predilection.